Home » Public Forums » GMCnet » Re: [GMCnet] Engine & transmission Oil Coolers.
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| Re: [GMCnet] Engine & transmission Oil Coolers. [message #280969 is a reply to message #280967] |
Mon, 29 June 2015 02:27   |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Bob,
Good effort!
Unfortunately that didn't determine the pressure the bypass valve would open, it checked the amount of spring pressure on the poppet
keeping it closed.
To test it you would have to apply pressure to the side of the poppet you can see in the photo linked below.
http://www.gmcmhphotos.com/photos/455-2f-403-engine-oil-flow-path/p49551-oil-cooler-2f-filter-adapter-inside.html
The surface area of the poppet exposed to oil pressure must be taken into consideration because it is a liquid pressure of 5.3 to
6.3 pounds PER SQUARE INCH applied to surface area of the bypass that opens it.
Looking at the photo I'd guess that the diameter of the poppet exposed to pressure is 3/8 inches (0.375 inches). Please check that
number with a vernier.
To calculate the surface area exposed to oil pressure is:
Pi times Radius2 (squared) equals Area.
3.14 times (0.192 times 0.192) equals 0.11045 square inches.
Now I'm stuck, for the life of me I can't remember (or even if I ever knew) how to calculate how much spring pressure it would take
to keep the bypass closed until 5.3 (84.3 ounces per square inch) to 6.3 psi (100.8 ounces per square inch) was applied to open the
bypass! DOUH!
HELP!!!
Regards,
Rob M.
The Pedantic Mechanic
-----Original Message-----
From: Bob Dunahugh
There was no simple way with a gauge. So I put a very sensitive scale on the bench. Placed a drinking straw in the center of the
scale. Zeroed the scale. Placed the top end of that straw in the center of the oil filter bypass disc. Pushed down slowly till the
disc opened. Roughly 6 oz. Then I flipped the oil filter bypass valve assembly over. Made a holder for the straw with a 8oz paper
cup on top of the straw. That was NOT a simple task. PROMISE. Weighed the cup with the straw to determine the combined weight. Put
the assembly in place, and put water in the cup till the bypass valve opened. Then weighed the water, cup, and straw. That came out
to be 6.07 oz. In short. That was what this valve is. But I'll bet that all others will be close. That spring is very, very thin.
As I've had others from GM cars out. And this one felt the same. Bob Dunahugh
I tested that oil filter bypass valve today. It opened at 6 oz of pressure. It's always bypassing some oil as we drive. I'm going
to be sending a post that will explain this.
Bob Dunahugh
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] Engine & transmission Oil Coolers. [message #280996 is a reply to message #280985] |
Mon, 29 June 2015 11:47 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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Billy,
I am not surprised that he has had no problems.
The available engine lube oils when our coaches were made were not nearly as temperature stable as they are today.
If I have to do an engine, I will probably put it back with a thermocouple in the lube oil and no cooler. Then if I am uncomfortable with what I am seeing, I will probably look up a Modine doughnut cooler like we used in the dyno labs for years. They were so inexpensive, that we did even bother to use them twice.
Matt
bdub wrote on Mon, 29 June 2015 10:36Rob, you know the Classics member that lives in Gladewater, TX. He has no trouble with contamination from the oil cooler and doesn't take a chance on hoses getting old and rupturing. He took that cooler adapter off and threw it away to start with many years ago. Pulls a car on a dolly everywhere he goes. Many 6 or 7 hundred mile trips through Colorado and back over the last 13 years. Never a problem.
Just another data point ...
bdub (and don't ask me about his temps, he don't worry about it)
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Engine & transmission Oil Coolers. [message #281009 is a reply to message #280983] |
Mon, 29 June 2015 15:39 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Bob,
You're going to think I'm nuts! I woke up at 4:00am and this subject popped into my mind! I went to my PC and downloaded my emails
and read the latest batch of emails Subject: Re: [GMCnet] Engine & transmission Oil Coolers.
A bulb came on and I realized that our engines came out of Oldsmobile Toronados and I'll bet that Toronados DID NOT COME with oil
coolers in the radiator!
I remembered that I had a CD with the manuals for a 67 Toronado (that's where I got the TH-425 Switch Pitch and 3.21 to 1 Planetary
Final Drive manuals) so I checked and sure enough the radiator in a 1967 Toronado (425 powered) had a transmission oil cooler but NO
engine oil cooler! Unfortunately according to Wikipedia the 455 was not introduced until 1968 so I cannot state unequivocally that
the radiators were the same, however, I'll bet dollars to donuts they were.
For the sake of this discussion I will make the following assumptions:
1) All Toronados from 1968 to 1978 were NOT equipped with engine oil coolers in the radiator
2) The oil filter base on the side of the block (part the oil cooler adapter and filter screw on to) is the same for the 425, 455,
and 403
3) The bypass valve in the oil filter bases for all three engines above is set to open at 5.3 to 6.3 psi
4) The pressure drop through the tubing, hoses, engine oil cooler; and filter is close to the 5.3 to 6.3 psi when all the parts are
clean
5) Engine oil bypasses the engine oil cooler and filter when the engine oil is COLD when all the parts are clean
6) Engine oil does not bypass the engine oil cooler in significant quantity when the engine reaches normal operating temperature
when all the parts are clean
Taking the above assumptions into consideration I believe that contamination from a poorly cleaned oil cooler getting into a newly
rebuilt engine does NOT cause the replacement engine to fail, I believe the residual contamination in the engine oil cooler
increases the pressure drop above the 5.3 to 6.3 psi and the engine oil cooler and filter are bypassed even when the engine reaches
normal operating temperature. This theory is supported by "stories" of newly quality rebuilt engines failing at low mileage. If it
was actual contamination from the failed engine getting into the rebuilt engine I believe the contamination would take out the
bearings a lot faster than that. Come to think of it a high volume pump would make this even worse as the flow rate of bypassed
unfiltered oil would be higher!
Look closely at this photo: http://www.gmcmhphotos.com/photos/455-2f-403-engine-oil-flow-path/p49550-bypass-poppet.html
Note the flat spot on the poppet at the 8:00 position - I believe that came from the poppet wearing on one of the three guides in
this photo: http://www.gmcmhphotos.com/photos/455-2f-403-engine-oil-flow-path/p49549-bypass-poppet-removed.html (sorry about the
fuzzy photo) because it was moving constantly as the engine sped up and slowed down varying the oil pump output pressure. The higher
the pressure the greater it would open.
This theory could be tested by installing "T" fittings on the outlet and returns to engine oil cooler adapter and connecting them to
a gage that measures pressure differential and then running the engine.
Have I got something here or am I FOS? ;-)
Regards,
Rob M.
The Pedantic Mechanic
-----Original Message-----
From: Bob Dunahugh
Rob. You are absolutely correct. All I wanted to show was that the bypass valve opens at a very low pressure on the bypass disc. I
wasn't really interested at that time the ounces per square inch number. The number that I came up with was higher than I expected.
I think that most readers think that all the oil from the pump is filtered 100% on each pass. It is after the oil goes thru the
pump enough times. It's this bypassed oil that had contamination in it that damaged the bearings. As to the contamination that's in
the cooler. I think the cleaning process used in that Jay Leno video does a great job. I'm not taking a chance. We're spending the
$200 for that after market cooler.Bob Dunahugh
There was no simple way with a gauge. So I put a very sensitive scale on the bench. Placed a drinking straw in the center of the
scale. Zeroed the scale. Placed the top end of that straw in the center of the oil filter bypass disc. Pushed down slowly till the
disc opened. Roughly 6 oz. Then I flipped the oil filter bypass valve assembly over. Made a holder for the straw with a 8oz paper
cup on top of the straw. That was NOT a simple task. PROMISE. Weighed the cup with the straw to determine the combined weight. Put
the assembly in place, and put water in the cup till the bypass valve opened. Then weighed the water, cup, and straw. That came out
to be 6.07 oz. In short. That was what this valve is. But I'll bet that all others will be close. That spring is very, very thin.
As I've had others from GM cars out. And this one felt the same. Bob Dunahugh
I tested that oil filter bypass valve today. It opened at 6 oz of pressure. It's always bypassing some oil as we drive. I'm going
to be sending a post that will explain this.
Bob Dunahugh
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] Engine & transmission Oil Coolers. [message #281215 is a reply to message #281009] |
Wed, 01 July 2015 17:20 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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USAussie wrote on Mon, 29 June 2015 15:39...Taking the above assumptions into consideration I believe that contamination from a poorly cleaned oil cooler getting into a newly
rebuilt engine does NOT cause the replacement engine to fail, I believe the residual contamination in the engine oil cooler
increases the pressure drop above the 5.3 to 6.3 psi and the engine oil cooler and filter are bypassed even when the engine reaches
normal operating temperature. This theory is supported by "stories" of newly quality rebuilt engines failing at low mileage. If it
was actual contamination from the failed engine getting into the rebuilt engine I believe the contamination would take out the
bearings a lot faster than that. Come to think of it a high volume pump would make this even worse as the flow rate of bypassed
unfiltered oil would be higher! ...
Rob I'm not sure I follow this paragraph. In one sentence you say you do NOT think a poorly cleaned oil cooler is responsible and in another you seem to say that crap in the cooler plugs up the filter and opens the bypass to...what? Contaminates from the uncleaned cooler or from the new engine not being filtered.
Seems to me that the bypass is the critical path...regardless of oil cooler being cleaned or not.
Don't I recall that some oil filters don't have a bypass or can we disable the bypass? If we went to the largest filter that would fit and changed the filter frequently, seems to me we'd have ALL oil filtered. That might be an issue in the frozen north.
Seems to me that we're closing on a possible explanation for 'sudden death syndrome' in new engines.
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
[Updated on: Wed, 01 July 2015 17:21] Report message to a moderator |
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| Re: [GMCnet] Engine & transmission Oil Coolers. [message #281223 is a reply to message #281215] |
Wed, 01 July 2015 18:47 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Senior Member |
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kerry pinkerton wrote on Wed, 01 July 2015 15:20USAussie wrote on Mon, 29 June 2015 15:39...Taking the above assumptions into consideration I believe that contamination from a poorly cleaned oil cooler getting into a newly
rebuilt engine does NOT cause the replacement engine to fail, I believe the residual contamination in the engine oil cooler
increases the pressure drop above the 5.3 to 6.3 psi and the engine oil cooler and filter are bypassed even when the engine reaches
normal operating temperature. This theory is supported by "stories" of newly quality rebuilt engines failing at low mileage. If it
was actual contamination from the failed engine getting into the rebuilt engine I believe the contamination would take out the
bearings a lot faster than that. Come to think of it a high volume pump would make this even worse as the flow rate of bypassed
unfiltered oil would be higher! ...
Rob I'm not sure I follow this paragraph. In one sentence you say you do NOT think a poorly cleaned oil cooler is responsible and in another you seem to say that crap in the cooler plugs up the filter and opens the bypass to...what? Contaminates from the uncleaned cooler or from the new engine not being filtered.
Seems to me that the bypass is the critical path...regardless of oil cooler being cleaned or not.
Don't I recall that some oil filters don't have a bypass or can we disable the bypass? If we went to the largest filter that would fit and changed the filter frequently, seems to me we'd have ALL oil filtered. That might be an issue in the frozen north.
Seems to me that we're closing on a possible explanation for 'sudden death syndrome' in new engines.
Kerry you are quite correct any crap in that cooler can find its way into the bearings if the bypass opens. I have considered pluging the bypass as i change the filter regular but I may just put more tension on the spring so it will take a larger pressure drop to open it
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: [GMCnet] Engine & transmission Oil Coolers. [message #281239 is a reply to message #281215] |
Wed, 01 July 2015 23:41 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Kerry,
OK, I'll clarify what I noted in my first email.
1) Oldsmobile 455 and 403 engines uses an oil filter that DOES NOT HAVE A BY-PASS! I have pasted a list of the ALL the oil filters
listed in the GMCMI Parts List at the bottom of this email. I had promised to check every one of them but unfortunately it's still
on my 'round toit list and will probably remain there ad infinitum, sorry, too many other irons in the fire. All I can suggest is
just use a Wix filter and be done with it! I bought a case of 12 Wix 51049 (largest media surface area available) from Amazon awhile
back. By accident they sent me TWO cases of 12 so I got lucky and have a lifetime supply for Double Trouble!
2) MM X-7525 / Section 6A - Engine / Page 6A-2 / ENGINE LUBRICATION SYSTEM (FIGURE 1) / Paragraph 2 / states: "The oil filter base
has a by-pass valve which in the event of filter restriction will open at 5.3 to 6.3 psi."
3) The 1967 Oldsmobile Toronado manual I have on CD shows that the Toronado did not have an engine oil cooler in the radiator all
there was is the oil filter base (with by-pass) and the oil filter (with no by-pass).
4) I was talking to Ken Frey the other day about the brass by-pass valve poppets he makes to replace the OEM poppets (which I
believe are micarta) in the oil filter base. I asked if he knew if the oil filter bases for the 455's and 403's in the Toronado were
the same as the 455's and 403's in GMC's and he said as far as he knew the answer was yes. As a young man Ken was a mechanic at an
Oldsmobile dealership and has a lot of experience working on Toronados.
5) If the pressure on the "inlet side" of the bypass valve poppet (what you can see in the photo linked below) is 5.3 to 6.3 psi
higher than the pressure on the spring side (you can't see) the bypass will open. That is the pressure differential caused by the
pressure drop as the oil flows:
a) Into the oil filter base
b) To the oil cooler adapter
c) Through the line from the oil cooler adapter to the oil cooler
d) Through oil cooler
e) Through the line from the oil cooler to the oil cooler adapter
f) Through the oil filter
g) Back into the oil filter base
http://www.gmcmhphotos.com/photos/455-2f-403-engine-oil-flow-path/p49551-oil-cooler-2f-filter-adapter-inside.html
6) I would think that the engineers at GMC responsible for the engine would have checked the pressure drop through the additional
oil system components that the GMC had that the Toronado didnt to assure that the pressure drop was less than 5.3 to 6.3 psi so the
bypass didn't open under normal operating conditions. Maybe they didn't and if the GMC has the same oil filter base as the Toronado
the 5.3 to 6.3 pressure drop may be too low considering the additional pressure drop caused by the oil flowing through the
additional components.
7) Bob Dunahugh believes that in the GMC the by-pass is always open.
8) I suspect that even on a 70° F day when the engine serviced with 10W-40 oil is being turned by the starter the by-pass opens.
After it starts it will continue to by-pass some oil flow until the engine reaches normal operating temp of 190° F. I suspect that
happens even if all the components listed in 4) are spotless.
9) I believe that if the engine oil cooler has not been cleaned properly and there is residual contamination in it from a failed
engine it causes the pressure drop to increase above 5.3 to 6.3 psi and the by-pass staying open all the time.
10) Bill Bramlet noted words along the line that he's seen hi-quality GMC engine rebuilds fail at relatively low mileage.
11) Ken Henderson just noted; "the engine seemed to be doing well for about 20,000 miles"
My conclusion from all this information is that particulate contamination from a failed engine that is not cleaned out of the oil
cooler getting into the replacement engine is NOT what causes the replacement engine to fail; the replacement engine fails because
the pressure drop through a contaminated oil cooler flow path is greater than 5.3 to 6.3 psi and the by-pass valve is constantly
open. The engine oil is being circulated WITHOUT filtration over a longer period of time.
How can we verify this theory:
1) Find a 1975 Oldsmobile Maintenance Manual and see if it notes the press the by-pass in the oil filter base opens
2) Find a 1975 Oldsmobile Parts Book and see if the oil filter base is the same part number as the one for our GMC engines
3) Install "T" fittings at the outlet and return of the oil filter base and connect a delta pressure gage and check what the
readings are
If anyone is interested in step 3) let me know and I'll find all the fittings, and gage needed to check this.
Also PLEASE watch the Hot Flush video on Jay Leno's garage;
http://www.hotflusher.com/automotive/Jay-Leno-Hot-Flush.cfm
pay particular attention to the following comments:
@ 1:05 minutes - Automatic Transmission Fluid is used because it has detergents and carries contamination well
@ 1:30 minutes - Oil cooler acts like a filter
@ 2:10 minutes - Forty (40) year old Lotus cooler - hmmm 40 year old GMC
@ 2:20 minutes - Second hand cooler cleaned is just as good as a new one if you can flush it out
@ 3:13 minutes - Fluid is heated to 193°F which is normal operating temp
@ 3:27 minutes - Cooler expands a bit from the heat and gets cleaned better
@ 4:40 minutes - Note how flow reverses with a hard pulse
@ 5:12 minutes - Note flow reversing on flow meter
@ 7:15 minutes - Note that the filter you check is 28 microns and the main filter is 10 micron
Read the independent testing: http://www.hotflusher.com/automotive/independent-test.cfm
Also note that there are eighty four testimonials from various shops that have them, if they didn't work why would the shops praise
the Hot Flush system?
Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
Oldsmobile 455 and 403 Oil Filters (NO BYPASS)
AC Delco PF-24
AC Delco (Discontinued) PF-45
AC Delco (New) PF-58
Atlas G-74
Atlas G-69
Car Quest 85045
Car Quest 85258
Fram PH-25
Fram PH-3429
Hastings T-222
Hastings LF230
Lee LF-24
Lee LF-45
Motorcraft FL-331
Motorcraft FL-9
NAPA Filters (FIL) 1045
NAPA Filters (FIL) 1258
Purolator (Replaced with new Number) PER-123
Purolator L20123
Purolator PER-33
Shell S-16
Shell S-28
Texaco T-16
Texaco T-23
Union PF-24
Union PF-45
Wix 51045 - http://www.summitracing.com/int/parts/wix-51045
Wix 51049 - http://www.summitracing.com/int/parts/wix-51049
Wix 51258 - http://www.summitracing.com/int/parts/wix-51258
-----Original Message-----
From: Kerry Pinkerton
Rob I'm not sure I follow this paragraph. In one sentence you say you do NOT think a poorly cleaned oil cooler is responsible and
in another you seem to say that crap in the cooler plugs up the filter and opens the bypass to...what? Contaminates from the
uncleaned cooler or from the new engine not being filtered.
Seems to me that the bypass is the critical path...regardless of oil cooler being cleaned or not.
Don't I recall that some oil filters don't have a bypass or can we disable the bypass? If we went to the largest filter that would
fit and changed the filter frequently, seems to me we'd have ALL oil filtered. That might be an issue in the frozen north.
Seems to me that we'e closing on a possible explanation for 'sudden death syndrome' in new engines.
--
Kerry
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GMCnet mailing list
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] Engine & transmission Oil Coolers. [message #281247 is a reply to message #280943] |
Thu, 02 July 2015 07:06 |
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SeanKidd
Messages: 747
Registered: June 2012
Location: Northern Neck Virginia
Karma: 4
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Senior Member |
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I have a little story, it's been almost exactly three years since I bought my a GMC, and three years and 15 minutes since I seized the engine due to a ruptured oil cooler line. I overlooked the possibility the oil cooler trap, or store contaminated oil. I rebuilt my engine and reinstalled with nice new stainless steel lines, but did nothing to the radiator. I ran edlebrock start-up oil for first 50 miles, then changed the oil...discarded filter. After Concerns with high oil consumption, and hearing about oil cooler contamination...I 💩.
Changed my oil, and cut open the filter, I gasped, the filter (Napa gold) was littered with visible crud, including shiny bits, like bass boat metal flake. I was very concerned, ran another few hundred miles and changed the oil again....cut open filter, it was spotless, even under a magnifying glass. I cut open filter every time, but will probably cease, now that I have my new aluminum radiator.
I probably dodged a bullet, but considering all the talk about filter bypass, how fouled does a filter need to be to lift a bypass?
Sean and Stephanie
73 Ex-CanyonLands 26' #317 "Oliver"
Hubler 1-Ton, Quad-Bags, Rear Disc, Reaction Arms, P.Huber TBs, 3.70:1 LSD Honda 6500 inverter gen.
Colonial Travelers
[Updated on: Thu, 02 July 2015 07:15] Report message to a moderator |
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| Re: [GMCnet] Engine & transmission Oil Coolers. [message #281248 is a reply to message #280985] |
Thu, 02 July 2015 07:11 |
bobby5832708
Messages: 237
Registered: November 2006
Location: Winter Springs FL
Karma: 3
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Senior Member |
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Billy,
There's another GMC running around without an oil cooler on it ..... mine.
There are several reasons I removed it, one being that no matter which gasket I used and even using a torque wrench to tighten to spec it always seeped oil. The second reason is that I don't run a GMC-motorhome radiator, the current rad does not have an oil cooler in it.
If I were pulling a towd through mountains in 100 degree weather I would probably add an external oil cooler like Kerry did but since I live in Florida and drive in the southeastern US where it's relatively flat and I don't tow I just drive the GMC and don't really care what the oil temp is. So far the original engine still runs fine with Chevron Delo 15-40 oil in it's crankcase.
A couple of weeks ago I did a 1000 mile trip through GA, SC, and FL. It was 102 in Santee SC and 100 in Brunswick GA, this is the hottest weather I've driven in so far without the oil cooler. The GMC didn't overheat and it still runs fine. I don't know if running without an oil cooler will shorten the life of the engine, it's already 41 years old so if it fails I would say age has something to do with it. I've got a spare 455 in the garage and need an excuse to do an engine swap but as long as the original 455 keeps running good I'm going to just keep driving.
JWID, YMMV, your engine might explode into a million pieces if you do what I've done, etc. etc.
Bob Heller
2017 Winnebago 29VE
Winter Springs FL
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| Re: [GMCnet] Engine & transmission Oil Coolers. [message #281249 is a reply to message #281239] |
Thu, 02 July 2015 07:56 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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Senior Member |
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Great response Rob. This is good stuff. A few debate points for clarification. I did these out of order because the flush comment kind of stands alone.
USAussie wrote on Wed, 01 July 2015 23:41 .... PLEASE watch the Hot Flush video on Jay Leno's garage;
http://www.hotflusher.com/automotive/Jay-Leno-Hot-Flush.cfm
pay particular attention to the following comments:...
I did watch the video to the end Rob. My concern is at the end where they put the 40 year old Lotus cooler (from an engine that is 4+ times smaller than our Olds (1600cc vs 6600CC or 7450) I would THINK that under normal operation the bigger the motor, the more 'stuff' that comes out. Regardless, they put the filter back on the Hot Flush machine for an HOUR and according to Jay still had stuff on the screen. I can't see 'Bubba' being that dilligent. That said, the Hot Flush machine seems like the way to go if someone is going to take the 'clean vs replace' option.
USAussie wrote on Wed, 01 July 2015 23:41...
7) Bob Dunahugh believes that in the GMC the by-pass is always open.
...I suspect that even on a 70° F day when the engine serviced with 10W-40 oil is being turned by the starter the by-pass opens.
After it starts it will continue to by-pass some oil flow until the engine reaches normal operating temp of 190° F. I suspect that
happens even if all the components listed in 4) are spotless.
This is a BIG DEAL... a Great Big Freaking Deal! The implication is that WE've been running non-filtered oil.
9) I believe that if the engine oil cooler has not been cleaned properly and there is residual contamination in it from a failed
engine it causes the pressure drop to increase above 5.3 to 6.3 psi and the by-pass staying open all the time.....[/quote]
But would that contamination, especially in a new engine with a high volume oil pump which certainly could break some of those contaminates loose due to the higher volume of flow. For that matter, new rebuilds almost always have higher oil pressure than the old engine which would also break stuff loose. Add the possibility that the oil cooler lines were reversed at the adapter and was 'backflushing'. My oil cooler lines had no clamp so knowing which one to put where was a 50/50 proposition without checking the manual diagram (which I did not do)
USAussie wrote on Wed, 01 July 2015 23:418)My conclusion from all this information is that particulate contamination from a failed engine that is not cleaned out of the oil
cooler getting into the replacement engine is NOT what causes the replacement engine to fail; the replacement engine fails because
the pressure drop through a contaminated oil cooler flow path is greater than 5.3 to 6.3 psi and the by-pass valve is constantly
open. The engine oil is being circulated WITHOUT filtration over a longer period of time.
But Rob, if there is enough contaminates to plug the filter and open the bypass, surely time would imply that additional contamination either from the oil cooler or the engine would go through the engine. It's almost a chicken or the egg thing. The engine fails due to contamination from 'somewhere' either internal from a dirty rebuild or external from contaminates 'stored' in the cooler. The bypass opening ALLOWS the crap into the engine but it's the contaminates that cause the damage....right?
USAussie wrote on Wed, 01 July 2015 23:41
How can we verify this theory:
1) Find a 1975 Oldsmobile Maintenance Manual and see if it notes the press the by-pass in the oil filter base opens
2) Find a 1975 Oldsmobile Parts Book and see if the oil filter base is the same part number as the one for our GMC engines
3) Install "T" fittings at the outlet and return of the oil filter base and connect a delta pressure gage and check what the
readings are
If anyone is interested in step 3) let me know and I'll find all the fittings, and gauge needed to check this.
That would show resistance in the cooler but the real question is how can we determine that the pressure relief valve is opening? That is the smoking gun imo.
What would happen if the bypass was disabled? Would it cause excessive pressure on startup or would the thicker cold oil not be able to circulate and cause a drop in oil pressure? Oil filters are cheap. I'd be willing to change my filter every 2-3 K miles
The other thing is this, regardless of contamination in the cooler (or the lack thereof) do we want or need the filter being bypassed? Unfiltered oil just makes me cringe.
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: [GMCnet] Engine & transmission Oil Coolers. [message #281250 is a reply to message #281247] |
Thu, 02 July 2015 07:58 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Sean,
The Oldsmobile 455 and 403 engines use an oil filter that DOES NOT HAVE a bypass in it, the bypass is located upstream of the oil
cooler and filter it is located in the oil filter base that is bolted to the side of the engine.
Here's a link to a photograph of the engine oil filter base; the accompanying text explains how it works.
http://www.gmcmhphotos.com/photos/455-2f-403-engine-oil-flow-path/p58288-oil-filter-base.html
Hey guys ain't it amazin' how the oil filter caught all the crap from the failed engine that was in the oil cooler - things that
make you go Hmmmmmmm? ;-)
Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: Sean Kidd
I have a little story, it's been almost exactly three years since I bought my a GMC, and a year and 15 minutes since I seized the
engine due to a ruptured oil cooler line. I overlooked the possibility the oil cooler trap, or store contaminated oil. I rebuilt
my engine and reinstalled with nice new stainless steel lines, but did nothing to the radiator. I ran edlebrock start-up oil for
first 50 miles, then changed the oil...discarded filter.
After Concerns with high oil consumption, and hearing about oil cooler contamination...I Changed my oil, and cut open the filter, I
gasped, the filter (Napa gold) was littered with visible crud, including shiny bits, like bass boat metal flake. I was very
concerned, ran another few hundred miles and changed the oil again....cut open filter, it was spotless, even under a magnifying
glass. I cut open filter every time, but will probably cease, now that I have my new aluminum radiator.
I probably dodged a bullet, but considering all the talk about filter bypass, how fouled does a filter need to be to lift a bypass?
--
Sean
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] Engine & transmission Oil Coolers. [message #281253 is a reply to message #281248] |
Thu, 02 July 2015 08:11 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Bob,
Somewhere along the line I was taught that maximum safe engine oil temp is 260°F. When the temperature goes beyond that it begins to
break down and loose its lubricating properties.
On other occasions Matt Colie provided more information on high oil temperature and it's effects on an engine and considering he was
an engine lab test guy I'd go with what he says about that subject.
Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: Bob Heller
Billy,
There's another GMC running around without an oil cooler on it ..... mine.
There are several reasons I removed it, one being that no matter which gasket I used and even using a torque wrench to tighten to
spec it always seeped oil. The second reason is that I don't run a GMC-motorhome radiator, the current rad does not have an oil
cooler in it.
If I were pulling a towd through mountains in 100 degree weather I would probably add an external oil cooler like Kerry did but
since I live in Florida and drive in the southeastern US where it's relatively flat and I don't tow I just drive the GMC and don't
really care what the oil temp is. So far the original engine still runs fine with Chevron Delo 15-40 oil in it's crankcase.
A couple of weeks ago I did a 1000 mile trip through GA, SC, and FL. It was 102 in Santee SC and 100 in Brunswick GA, this is the
hottest weather I've driven in so far without the oil cooler. The GMC didn't overheat and it still runs fine. I don't know if
running without an oil cooler will shorten the life of the engine, it's already 41 years old so if it fails I would say age has
something to do with it. I've got a spare 455 in the garage and need an excuse to do an engine swap but as long as the original 455
keeps running good I'm going to just keep driving.
JWID, YMMV, your engine might explode into a million pieces if you do what I've done, etc. etc.
--
Bob
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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