Home » Public Forums » GMCnet » 100 lb of oil pressure
| 100 lb of oil pressure [message #215600] |
Wed, 24 July 2013 21:23  |
C Boyd
Messages: 2629
Registered: April 2006
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One of our Dixielanders at Calhoun rally drove in with no issues except shift cable froze up. We got it freed up and back on the next day and started it to check and the engine puked 3 qts out before we could shut it off. Coming out from oil filter base. Found it loose, tightened it up and started it again, puked out 3 more qts. Replaced the gasket with a new one and did not leak till the next morning when he started to leave and it had a leak. Removed the oil filter and replaced with new oil filter and tightened with wrench and saw no leaks. All seemed good till he started to leave Sunday and found the dash oil pressure gauge was pegged on high and the manual tube gauge was pegged on 80lb. He said both gauges were acting normal on the trip down with ~ 45 lb. Since both were acting wacky and the oil blowing out previously he decided to call AAA and haul it home. He contacted me and said he bought a new 100 lb manual oil pressure gauge and installed at front of engine in oil pressure sending unit port and when He started it, it pegged at 100 lb. I`m thinkin the oil pump relief valve is stuck closed?? I have heard of them getting crud and no oil pressure at idle but never heard of it sticking closed and building over 100 lb of pressure. If the cooler, lines, filter, or bypass valve was clogged the oil pump still should not build 100 lb cause of the relief valve. I would think if a passage was clogged it would not register 100 lb at front of engine?? Anybody got any Idears except digging the oil pump out??? Is there anyway the bypass valve could cause this???
C. Boyd
76 Crestmont
East Tennessee
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| Re: 100 lb of oil pressure [message #215602 is a reply to message #215600] |
Wed, 24 July 2013 21:31  |
Otterwan
Messages: 946
Registered: July 2013
Location: Lynnwood (north of Seattl...
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I assume since you didn't mention it the engine temperature was OK, and you weren't using straight 50wt oil. That pretty much just leaves the bypass valve on the oil pump. It really isn't that hard to get to on these engines. Not fun, but not hard.
1977 Birchaven, Lynnwood WA - "We may not be able to stop all evil in the world, but I know that how we treat one another is entirely up to us."
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| Re: 100 lb of oil pressure [message #215604 is a reply to message #215602] |
Wed, 24 July 2013 21:45 |
C Boyd
Messages: 2629
Registered: April 2006
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Temp was running 1/2 on gauge on trip down,but do not know which sending unit it had. We did add about a gallon or so of water and the overflow tank had a hole in it and replaced the 16 lb cap with a new 9 lb. Using 10-30 Delo. The coach had been sitting for a while when he bought it and this was first trip since he had it. 50 miles. Easiest way I can figure is to drop tranny, unhook motor stuff and raise it up enough to remove oil pan.
| Otterwan wrote on Wed, 24 July 2013 22:31 |
I assume since you didn't mention it the engine temperature was OK, and you weren't using straight 50wt oil. That pretty much just leaves the bypass valve on the oil pump. It really isn't that hard to get to on these engines. Not fun, but not hard.
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C. Boyd
76 Crestmont
East Tennessee
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| Re: 100 lb of oil pressure [message #215605 is a reply to message #215600] |
Wed, 24 July 2013 22:06 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
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I agree, by pass (pressure relief) valve at the oil pump. Probably a mechanical issue, but it could just be sludged up.
You could try dumping the oil and filling it with ATF or some other high detergent thin 5 to 10 w oil. Then start it and let it idle only. DO NOT DRIVE IT. There is a chance you can free up that stuck valve. If you do not want to run it you could do the above and pull the distributor run the pump with a drill for an hour or so to wee if you can loosen it up.,
What bothers me is he was driving it normally just prior to that episode so I would not expect it to stick from oil residue byproducts. That is why I'm voting for a mechanical problem with that valve and it probably will need to be replaced.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] 100 lb of oil pressure [message #215606 is a reply to message #215604] |
Wed, 24 July 2013 22:37 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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I'm with KenB: Drive the oil pump with a drill since that's trivially
easy. If the pressure's high that way, you'll know almost for sure that
it's the oil pressure relief valve on the pump. Then drain the oil and
replace it with ATF, Marvel Mystery, or something similar, and run the heck
out of the drill. That will either cure the problem or convince you that
pulling the pan's not such a big job after all.
If the flush does "cure" the problem, I'd sure flush the whole engine good,
check the condition of the flushing oil carefully, cut the oil filter open,
etc, etc. I just can't get rid of the images of the underside of turkey
trays from "unmolested" engines. Worry, worry,...
Ken H.
On Jul 24, 2013 7:46 PM, "Charles Boyd" <covered-wagon@comcast.net> wrote:
>
>
> Temp was running 1/2 on gauge on trip down,but do not know which sending
> unit it had. We did add about a gallon or so of water and the overflow tank
> had a hole in it and replaced the 16 lb cap with a new 9 lb. Using 10-30
> Delo. The coach had been sitting for a while when he bought it and this was
> first trip since he had it. 50 miles. Easiest way I can figure is to drop
> tranny, unhook motor stuff and raise it up enough to remove oil pan.
>
>
> Otterwan wrote on Wed, 24 July 2013 22:31
> > I assume since you didn't mention it the engine temperature was OK, and
> you weren't using straight 50wt oil. That pretty much just leaves the
> bypass valve on the oil pump. It really isn't that hard to get to on these
> engines. Not fun, but not hard.
>
>
> --
> C. Boyd
> 76 Crestmont
> East Tennessee
> _______________________________________________
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] 100 lb of oil pressure [message #215628 is a reply to message #215606] |
Thu, 25 July 2013 07:50 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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G'day,
Probably won't do anything but just for the hell of it use a reversing drill and spin the oil pump in both directions?
Regards,
Rob M.
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org [mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Ken Henderson
Sent: Wednesday, July 24, 2013 10:37 PM
To: gmclist
Subject: Re: [GMCnet] 100 lb of oil pressure
I'm with KenB: Drive the oil pump with a drill since that's trivially
easy. If the pressure's high that way, you'll know almost for sure that
it's the oil pressure relief valve on the pump. Then drain the oil and
replace it with ATF, Marvel Mystery, or something similar, and run the heck
out of the drill. That will either cure the problem or convince you that
pulling the pan's not such a big job after all.
If the flush does "cure" the problem, I'd sure flush the whole engine good,
check the condition of the flushing oil carefully, cut the oil filter open,
etc, etc. I just can't get rid of the images of the underside of turkey
trays from "unmolested" engines. Worry, worry,...
Ken H.
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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] 100 lb of oil pressure [message #215631 is a reply to message #215630] |
Thu, 25 July 2013 08:24 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Larry,
I am going to be making a presentation on the oil flow path in 403 and 455 Oldsmobile engines at Branson and Coos Bay because there
seems to be a lot of confusion and disagreement about this system. I sent in an earlier email that John Sharpe and I put together to
try and explain the flow path.
To be clear there let's first define the two valves system that can effect oil pressure:
1) The oil pump has a pressure regulator (see X-7525 pg 6A- 43 Figure 38 - Oil Pump Exploded View). I checked the MM but can't find
what the pressure that regulator is set for; I have "heard" that it is around 50 psi. The oil pressure test is on page 6A-26 and it
notes ". Oil pressure should be at idle - 7psi min. 1500-3000 rpm - 35psi min."
2) The second valve is in the Oil Filter Base (see X-7525 pg 6A-26 Figure 4 Oil filter). It is a valve that opens at 5.3 to 6.3 psi
and bypasses everything down stream of the Oil Filter Base.
If the oil filter was plugged that valve would open and you would not get 100 PSI.
Regards,
Rob M.
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org [mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Larry
Sent: Thursday, July 25, 2013 8:04 AM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] 100 lb of oil pressure
C Boyd wrote on Wed, 24 July 2013 21:23
> . Replaced the gasket with a new one and did not leak till the next morning when he started to leave and it had a leak. Removed
the oil filter and replaced with new oil filter and tightened with wrench and saw no leaks. All seemed good till he started to
leave Sunday and found the dash oil pressure gauge was pegged on high and the manual tube gauge was pegged on 80lb. He said both
gauges were acting normal on the trip down with ~ 45 lb.
You replaced the oil filter?? Any chance you got a bad oil filter? What's it gonna cost to get a new Wix filter? Might be a simple
fix. JWID
--
Larry :)
78 Royale w/500 Caddy
Menomonie, WI.
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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] 100 lb of oil pressure [message #215635 is a reply to message #215631] |
Thu, 25 July 2013 08:53 |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
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Ahhhh...right...Funny coincedence though, isn't it...
| Robert Mueller wrote on Thu, 25 July 2013 08:24 |
Larry,
I am going to be making a presentation on the oil flow path in 403 and 455 Oldsmobile engines at Branson and Coos Bay because there
seems to be a lot of confusion and disagreement about this system. I sent in an earlier email that John Sharpe and I put together to
try and explain the flow path.
To be clear there let's first define the two valves system that can effect oil pressure:
1) The oil pump has a pressure regulator (see X-7525 pg 6A- 43 Figure 38 - Oil Pump Exploded View). I checked the MM but can't find
what the pressure that regulator is set for; I have "heard" that it is around 50 psi. The oil pressure test is on page 6A-26 and it
notes ". Oil pressure should be at idle - 7psi min. 1500-3000 rpm - 35psi min."
2) The second valve is in the Oil Filter Base (see X-7525 pg 6A-26 Figure 4 Oil filter). It is a valve that opens at 5.3 to 6.3 psi
and bypasses everything down stream of the Oil Filter Base.
If the oil filter was plugged that valve would open and you would not get 100 PSI.
Regards,
Rob M.
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org [mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Larry
Sent: Thursday, July 25, 2013 8:04 AM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] 100 lb of oil pressure
C Boyd wrote on Wed, 24 July 2013 21:23
> . Replaced the gasket with a new one and did not leak till the next morning when he started to leave and it had a leak. Removed
the oil filter and replaced with new oil filter and tightened with wrench and saw no leaks. All seemed good till he started to
leave Sunday and found the dash oil pressure gauge was pegged on high and the manual tube gauge was pegged on 80lb. He said both
gauges were acting normal on the trip down with ~ 45 lb.
You replaced the oil filter?? Any chance you got a bad oil filter? What's it gonna cost to get a new Wix filter? Might be a simple
fix. JWID
--
Larry 
78 Royale w/500 Caddy
Menomonie, WI.
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Larry
78 Royale w/500 Caddy
Menomonie, WI.
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| Re: 100 lb of oil pressure [message #215637 is a reply to message #215600] |
Thu, 25 July 2013 09:14 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
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| C Boyd wrote on Wed, 24 July 2013 22:23 |
One of our Dixielanders at Calhoun rally drove in with no issues except shift cable froze up. We got it freed up and back on the next day and started it to check and the engine puked 3 qts out before we could shut it off. Coming out from oil filter base. Found it loose, tightened it up and started it again, puked out 3 more qts. Replaced the gasket with a new one and did not leak till the next morning when he started to leave and it had a leak. Removed the oil filter and replaced with new oil filter and tightened with wrench and saw no leaks. All seemed good till he started to leave Sunday and found the dash oil pressure gauge was pegged on high and the manual tube gauge was pegged on 80lb. He said both gauges were acting normal on the trip down with ~ 45 lb. Since both were acting wacky and the oil blowing out previously he decided to call AAA and haul it home. He contacted me and said he bought a new 100 lb manual oil pressure gauge and installed at front of engine in oil pressure sending unit port and when He started it, it pegged at 100 lb.
-I`m thinkin the oil pump relief valve is stuck closed??
-I have heard of them getting crud and no oil pressure at idle but never heard of it sticking closed and building over 100 lb of pressure.
-If the cooler, lines, filter, or bypass valve was clogged the oil pump still should not build 100 lb cause of the relief valve.
-I would think if a passage was clogged it would not register 100 lb at front of engine??
-Anybody got any Idears except digging the oil pump out???
-Is there anyway the bypass valve could cause this???
|
Chuck,
(I isolated your thought so I could think about them.)
Most oil pumps won't do this if they have to..
There are lots of places for lube oil to go before the sender, so an upstream plug simply could not cause this.
We get back to - It has to be a new pump with very thick oil to get there. And, that has to be one stout wad of coke to not blow out at 100 psi. And, what ever is plugging the relief valve had to get there through the pick up screen and the pump gears.
I like KenB's idea of running the pump with a drill motor. Draining the oil and running the pump in kerosene or Marvel oil might be a good idea too, as one of those might soften the coke and get it out of there.
But, I guess the idea I like best, but hate at the same time is to drop the trans, drop the pan and have a good look at what the (deleted by editor) is going on in that pump. This may be the least expensive way to save that engine.
Matt
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] 100 lb of oil pressure [message #215649 is a reply to message #215600] |
Thu, 25 July 2013 11:07 |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
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I would suggest that a telephone call to Dick Paterson might help diagnose this problem.
Emery Stora
On Jul 24, 2013, at 8:23 PM, Charles Boyd wrote:
>
>
> One of our Dixielanders at Calhoun rally drove in with no issues except shift cable froze up. We got it freed up and back on the next day and started it to check and the engine puked 3 qts out before we could shut it off. Coming out from oil filter base. Found it loose, tightened it up and started it again, puked out 3 more qts. Replaced the gasket with a new one and did not leak till the next morning when he started to leave and it had a leak. Removed the oil filter and replaced with new oil filter and tightened with wrench and saw no leaks. All seemed good till he started to leave Sunday and found the dash oil pressure gauge was pegged on high and the manual tube gauge was pegged on 80lb. He said both gauges were acting normal on the trip down with ~ 45 lb. Since both were acting wacky and the oil blowing out previously he decided to call AAA and haul it home. He contacted me and said he bought a new 100 lb manual oil pressure gauge and installed at front of engine in
o
> il pressure sending unit port and when He started it, it pegged at 100 lb. I`m thinkin the oil pump relief valve is stuck closed?? I have heard of them getting crud and no oil pressure at idle but never heard of it sticking closed and building over 100 lb of pressure. If the cooler, lines, filter, or bypass valve was clogged the oil pump still should not build 100 lb cause of the relief valve. I would think if a passage was clogged it would not register 100 lb at front of engine?? Anybody got any Idears except digging the oil pump out??? Is there anyway the bypass valve could cause this???
> --
> C. Boyd
> 76 Crestmont
> East Tennessee
> _______________________________________________
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| Re: 100 lb of oil pressure [message #215689 is a reply to message #215600] |
Thu, 25 July 2013 18:20 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Would a collapsed cooler hose or blocked cooler cause this? Why not unthread the cooler adaptor and screw a new filter right to the filter addaptor as a test. Not 100% clear of the metering point but it onlymakes sense that there is not 100 psi at the galleys, Think about the collapsed brake hose scenario... This test is 5 mins to execute. The bypass valve should be closed at idle.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: 100 lb of oil pressure [message #215692 is a reply to message #215600] |
Thu, 25 July 2013 19:11 |
kingd
Messages: 592
Registered: June 2004
Karma: 2
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I shimmed the oil pump pressure relief spring on a SOB. Access to the spring is external to the engine. I only added a couple of very thin washers. ( because I didn't like what the stock oil pressure guage was reading.) Started the engine and at fast idle blew the filter off. Installed new filter and good mechanical oil
pressure guage. Guess what, about 1/2 up the scale on the stock gauge was 80 psi at idle. Remove the washers and everything was good. 45 psi hot at anything above 1500 rpm. Shop maual says don't mess with pressure relief valve until pressure is confirmed with a known good gauge. As it says on my Tool Time shirt, "real men don't need instructions" LOL
DAVE KING
lurker, wannabe
Toronto, Ontario, Canada
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| Re: [GMCnet] 100 lb of oil pressure [message #215706 is a reply to message #215664] |
Thu, 25 July 2013 22:34 |
GMC_LES
Messages: 569
Registered: October 2009
Location: Montreal
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You guys are all missing an important fact here.
The original message stated the following:
"He contacted me and said he bought a new 100 lb manual oil pressure gauge and installed at front of engine in oil pressure sending unit port and when He started it, it pegged at 100 lb. "
With that info, it is obvious that the oil is getting to the engine oil galleys, so the problem is not external. I have seen stuck relief valves on the old VW diesels do the same thing on cold start up so my money is on the oil pump relief valve.
Les Burt
Montreal
On 2013-07-25, at 1:47 PM, Hal Kading <halkading@fastwave.biz> wrote:
>
>
> This is really weird. Engine would have to be really tight to peg oil pressure gages at idle in summertime. Any body look at the oil to see if it is really 10-30? Problem to come and go doesn't make sense either. Blowing out filter base gasket indicates stoppage or restriction is downstream from filter adapter relief valve. I give up - no ideas that make any sense.
>
> Hal Kading 78 Buskirk Las Cruces NM
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Les Burt
Montreal
1975 Eleganza 26ft
A work in Progress
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