Home » Public Forums » GMCnet » Got Hot- Fan Clutch
| Got Hot- Fan Clutch [message #179486] |
Wed, 08 August 2012 00:50  |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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Senior Member |
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Going to church family camp. Roared up to 3000 feet and all was well. Ran air in 95 degree weather. Then we started the twisty-turny road, causing 15 mph speeds. Ran in low most of the time.
Temp went to 210. I thought, hmmm. Air is off.
Temp went to 220. I thought, hmmm, fan clutch ought to engage.
Temp went to 230. I thought, I have to stop because the fan clutch is not engaging.
So we stopped. This made wifie a little alarmed as we had just passed the place where the transmission let go last year. It is not good to alarm wifie.
What I thought I knew:
Did the old clutch roar when you first start the engine? Absolutely. Didn't let loose for a mile or two and must be above 2000 rpm to finally release. Sounded like a B-52 taking off. (By the way, after we stopped to cool for a few minutes and ate lunch, the fan clutch roared for a bit only to stop and not engage again, even at 220 on the second leg.)
Could you twirl the old clutch fan by hand? No. Couldn't get more than a blade or two. Seemed very stiff.
So, I thought that meant the clutch was OK? Not mine, apparently.
How did it look when it came off? Like it came out of the box. I tried to put it over the kitchen stove to see the little bimetal thingy turn the shaft, but gave up and went to NAPA for a new one.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: [GMCnet] Got Hot- Fan Clutch [message #179527 is a reply to message #179486] |
Wed, 08 August 2012 11:34  |
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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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George,
Funny you should mention this; on the way to pickup a rental car in Santa Fe all of a sudden the Digi-Panel began screaming! I
looked over and sure enough the temp was beyond 212. I pulled over and shut the coach down. Waited a few minutes and popped the
engine cover, reached in and could spin the fan easily. We sat there for a few minutes while I called Enterprise and told them we
would be late than started the coach back up. The Digi-Panel screamed for a few seconds then stopped and the temperature dropped. I
drove around the corner to a Shell station and parked under a tree. Called Enterprise and told them where I was (about 5 blocks from
their location) and asked if they would come and pick me up, which they did. While I was waiting I called Marc and told him it
looked like I would be changing the fan clutch, he asked if I needed help but since it was a simple task I noted not really. At any
rate Enterprise arrived and I went back to their location and completed the paperwork. By the time I got back to the GMC it had been
sitting for around 30 minutes or so. For the hell of it I started it up and Voila - EVERYTHING NORMAL! HUH?
I let it idle for a few minutes and everything remained normal and I could hear the fan turning.
Called Marc back and we decided to "give it a go" so off I went with Helen behind me in the rental car.
The route from Santa Fe to Madrid is relatively flat and I could hear the fan clutch kick on and off regularly. The last couple of
miles is a pretty steep climb and that concerned me but no problems. Marc met us at the start of the road to his house and led us
in.
The next day we talked about it and even though the fan clutch seemed to have fixed itself we decided to replace it since I had a
spare.
We made it from Santa Fe to Taos (SERIOUSLY UPHILL) with no fan problems. There was another problem which I will bring up in a
separate email.
Regards,
Rob M.
-----Original Message-----
From: George Beckman
Going to church family camp. Roared up to 3000 feet and all was well. Ran air in 95 degree weather. Then we started the twisty-turny
road, causing 15 mph speeds. Ran in low most of the time.
Temp went to 210. I thought, hmmm. Air is off.
Temp went to 220. I thought, hmmm, fan clutch ought to engage.
Temp went to 230. I thought, I have to stop because the fan clutch is not engaging.
So we stopped. This made wifie a little alarmed as we had just passed the place where the transmission let go last year. It is not
good to alarm wifie.
What I thought I knew:
Did the old clutch roar when you first start the engine? Absolutely. Didn't let loose for a mile or two and must be above 2000 rpm
to finally release. Sounded like a B-52 taking off. (By the way, after we stopped to cool for a few minutes and ate lunch, the fan
clutch roared for a bit only to stop and not engage again, even at 220 on the second leg.)
Could you twirl the old clutch fan by hand? No. Couldn't get more than a blade or two. Seemed very stiff.
So, I thought that meant the clutch was OK? Not mine, apparently.
How did it look when it came off? Like it came out of the box. I tried to put it over the kitchen stove to see the little bimetal
thingy turn the shaft, but gave up and went to NAPA for a new one.
--
George
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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] Got Hot- Fan Clutch [message #179532 is a reply to message #179527] |
Wed, 08 August 2012 11:47 |
Gary Worobec
Messages: 867
Registered: May 2005
Karma: -1
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Senior Member |
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Rob, If you recall Steve F did a bang up presentation at one of the rallies
on GMC cooling and specifically fan clutches. Here it is.
http://tinyurl.com/9ms8leb
I think he indicated that there was a huge difference in fan clutches both
in quality and operation. Because of this I got a new HD one from JimK and
its worked well for several years.
Thanks
Gary and Joanne Worobec
1973 GMC Glacier
Anza, CA
----- Original Message -----
From: "Rob Mueller" <robmueller@iinet.net.au>
To: <gmclist@temp.gmcnet.org>
Sent: Wednesday, August 08, 2012 9:34 AM
Subject: Re: [GMCnet] Got Hot- Fan Clutch
> George,
>
> Funny you should mention this; on the way to pickup a rental car in Santa
> Fe all of a sudden the Digi-Panel began screaming! I
> looked over and sure enough the temp was beyond 212. I pulled over and
> shut the coach down. Waited a few minutes and popped the
> engine cover, reached in and could spin the fan easily. We sat there for a
> few minutes while I called Enterprise and told them we
> would be late than started the coach back up. The Digi-Panel screamed for
> a few seconds then stopped and the temperature dropped. I
> drove around the corner to a Shell station and parked under a tree. Called
> Enterprise and told them where I was (about 5 blocks from
> their location) and asked if they would come and pick me up, which they
> did. While I was waiting I called Marc and told him it
> looked like I would be changing the fan clutch, he asked if I needed help
> but since it was a simple task I noted not really. At any
> rate Enterprise arrived and I went back to their location and completed
> the paperwork. By the time I got back to the GMC it had been
> sitting for around 30 minutes or so. For the hell of it I started it up
> and Voila - EVERYTHING NORMAL! HUH?
>
> I let it idle for a few minutes and everything remained normal and I could
> hear the fan turning.
>
> Called Marc back and we decided to "give it a go" so off I went with Helen
> behind me in the rental car.
>
> The route from Santa Fe to Madrid is relatively flat and I could hear the
> fan clutch kick on and off regularly. The last couple of
> miles is a pretty steep climb and that concerned me but no problems. Marc
> met us at the start of the road to his house and led us
> in.
>
> The next day we talked about it and even though the fan clutch seemed to
> have fixed itself we decided to replace it since I had a
> spare.
>
> We made it from Santa Fe to Taos (SERIOUSLY UPHILL) with no fan problems.
> There was another problem which I will bring up in a
> separate email.
>
> Regards,
> Rob M.
>
>
> -----Original Message-----
> From: George Beckman
>
> Going to church family camp. Roared up to 3000 feet and all was well. Ran
> air in 95 degree weather. Then we started the twisty-turny
> road, causing 15 mph speeds. Ran in low most of the time.
>
> Temp went to 210. I thought, hmmm. Air is off.
> Temp went to 220. I thought, hmmm, fan clutch ought to engage.
> Temp went to 230. I thought, I have to stop because the fan clutch is not
> engaging.
>
> So we stopped. This made wifie a little alarmed as we had just passed the
> place where the transmission let go last year. It is not
> good to alarm wifie.
>
> What I thought I knew:
>
> Did the old clutch roar when you first start the engine? Absolutely.
> Didn't let loose for a mile or two and must be above 2000 rpm
> to finally release. Sounded like a B-52 taking off. (By the way, after we
> stopped to cool for a few minutes and ate lunch, the fan
> clutch roared for a bit only to stop and not engage again, even at 220 on
> the second leg.)
>
> Could you twirl the old clutch fan by hand? No. Couldn't get more than a
> blade or two. Seemed very stiff.
>
> So, I thought that meant the clutch was OK? Not mine, apparently.
>
> How did it look when it came off? Like it came out of the box. I tried to
> put it over the kitchen stove to see the little bimetal
> thingy turn the shaft, but gave up and went to NAPA for a new one.
> --
> George
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: [GMCnet] Got Hot- Fan Clutch [message #179542 is a reply to message #179532] |
Wed, 08 August 2012 13:04 |
Ray Erspamer
Messages: 1707
Registered: May 2007
Location: Milwaukee Wisconsin
Karma: -3
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Senior Member |
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|
I've had my best luck running the HEAVY DUTY which is currently a Hayden 2747.
I get too much fan cycling with the severe duty along with squealing belts, etc.
On our recent trip with the new temp gauge installed and ambient outside temp
near 90, we stayed consistently around the 195 degree range with the fan clutch
cycling and pretty much unnoticeable.
Ray
Ray & Lisa
78 Royale "Great Lakes Eagle"
Center Kitchen TZE368V101144
Wauwatosa, Wisconsin 53226
Email: 78GMC-Royale@att.net
414-745-3188
Web Site: http://ray-lisa.page.tl/
________________________________
From: Gary Worobec <gtw5@earthlink.net>
To: gmclist@temp.gmcnet.org
Sent: Wed, August 8, 2012 11:47:49 AM
Subject: Re: [GMCnet] Got Hot- Fan Clutch
Rob, If you recall Steve F did a bang up presentation at one of the rallies
on GMC cooling and specifically fan clutches. Here it is.
http://tinyurl.com/9ms8leb
I think he indicated that there was a huge difference in fan clutches both
in quality and operation. Because of this I got a new HD one from JimK and
its worked well for several years.
Thanks
Gary and Joanne Worobec
1973 GMC Glacier
Anza, CA
----- Original Message -----
From: "Rob Mueller" <robmueller@iinet.net.au>
To: <gmclist@temp.gmcnet.org>
Sent: Wednesday, August 08, 2012 9:34 AM
Subject: Re: [GMCnet] Got Hot- Fan Clutch
> George,
>
> Funny you should mention this; on the way to pickup a rental car in Santa
> Fe all of a sudden the Digi-Panel began screaming! I
> looked over and sure enough the temp was beyond 212. I pulled over and
> shut the coach down. Waited a few minutes and popped the
> engine cover, reached in and could spin the fan easily. We sat there for a
> few minutes while I called Enterprise and told them we
> would be late than started the coach back up. The Digi-Panel screamed for
> a few seconds then stopped and the temperature dropped. I
> drove around the corner to a Shell station and parked under a tree. Called
> Enterprise and told them where I was (about 5 blocks from
> their location) and asked if they would come and pick me up, which they
> did. While I was waiting I called Marc and told him it
> looked like I would be changing the fan clutch, he asked if I needed help
> but since it was a simple task I noted not really. At any
> rate Enterprise arrived and I went back to their location and completed
> the paperwork. By the time I got back to the GMC it had been
> sitting for around 30 minutes or so. For the hell of it I started it up
> and Voila - EVERYTHING NORMAL! HUH?
>
> I let it idle for a few minutes and everything remained normal and I could
> hear the fan turning.
>
> Called Marc back and we decided to "give it a go" so off I went with Helen
> behind me in the rental car.
>
> The route from Santa Fe to Madrid is relatively flat and I could hear the
> fan clutch kick on and off regularly. The last couple of
> miles is a pretty steep climb and that concerned me but no problems. Marc
> met us at the start of the road to his house and led us
> in.
>
> The next day we talked about it and even though the fan clutch seemed to
> have fixed itself we decided to replace it since I had a
> spare.
>
> We made it from Santa Fe to Taos (SERIOUSLY UPHILL) with no fan problems.
> There was another problem which I will bring up in a
> separate email.
>
> Regards,
> Rob M.
>
>
> -----Original Message-----
> From: George Beckman
>
> Going to church family camp. Roared up to 3000 feet and all was well. Ran
> air in 95 degree weather. Then we started the twisty-turny
> road, causing 15 mph speeds. Ran in low most of the time.
>
> Temp went to 210. I thought, hmmm. Air is off.
> Temp went to 220. I thought, hmmm, fan clutch ought to engage.
> Temp went to 230. I thought, I have to stop because the fan clutch is not
> engaging.
>
> So we stopped. This made wifie a little alarmed as we had just passed the
> place where the transmission let go last year. It is not
> good to alarm wifie.
>
> What I thought I knew:
>
> Did the old clutch roar when you first start the engine? Absolutely.
> Didn't let loose for a mile or two and must be above 2000 rpm
> to finally release. Sounded like a B-52 taking off. (By the way, after we
> stopped to cool for a few minutes and ate lunch, the fan
> clutch roared for a bit only to stop and not engage again, even at 220 on
> the second leg.)
>
> Could you twirl the old clutch fan by hand? No. Couldn't get more than a
> blade or two. Seemed very stiff.
>
> So, I thought that meant the clutch was OK? Not mine, apparently.
>
> How did it look when it came off? Like it came out of the box. I tried to
> put it over the kitchen stove to see the little bimetal
> thingy turn the shaft, but gave up and went to NAPA for a new one.
> --
> George
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
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Ray Erspamer
78 GMC Royale Center Kitchen
403, 3.70 Final Drive
Holley Sniper Quadrajet EFI System,
Holley Hyperspark Ignition System
414-484-9431
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| Re: [GMCnet] Got Hot- Fan Clutch [message #179548 is a reply to message #179544] |
Wed, 08 August 2012 14:06 |
|
USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Larry,
I agree with you which is why I was quite surprised that on the hour long drive from Santa Fe out to Madrid it worked perfectly. The
reasons we replaced it were; I had a spare, it's an easy job (especially with one guy working on top of the engine and the second
under, and as you noted; "It's one of those things that I'd not gamble with. . ."
Regards,
Rob M.
-----Original Message-----
From: Larry Davick
Rob,
I don't think fan clutches fix themselves. When my clutch locked up on our way to Orange County I thought, well, at least it failed
locked up! Sonofagun but it let loose just as traffic got bad.
It's one of those things that I'd not gamble with. 30 minutes and some very sore fingertips later we were on the road.
JWID.
--
Larry
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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: Got Hot- Fan Clutch [message #179555 is a reply to message #179486] |
Wed, 08 August 2012 15:38 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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I'm wondering if that valve that the thermal coil operates can stick after months of not being used. That kind of sounds like what you had. Also could a small piece of dirt or a bug jam that temperature sensing coil.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Got Hot- Fan Clutch [message #179572 is a reply to message #179562] |
Wed, 08 August 2012 18:41 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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| ahamilto wrote on Wed, 08 August 2012 16:52 |
| Ken Burton wrote on Wed, 08 August 2012 16:44 |
They usually stay engaged until 10 or 15 mph when they are cold.
|
In that case I will need go on a longer test run before I render judgement that it is shot.
|
I have never actually looked at the speedo but I start mine and drive down a 400 foot driveway Then I turn and start down the street. I hear it drop out as I accelerate. I'm guessing it is between 10 and 20 mph.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Got Hot- Fan Clutch [message #179573 is a reply to message #179560] |
Wed, 08 August 2012 18:43 |
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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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| ahamilto wrote on Wed, 08 August 2012 17:27 |
While we are on the subject, is there a fix (other than replacement) for one that stays engaged on engine start instead of cutting out after a few seconds?
|
Aham,
It may not be everybody's fix, but when ours wouldn't unlock and we were on our way to somewhere, I opened the engine room door and put my hand on the fan clutch. It was cool, but my hand came away dirty, greasy and nasty.
So, as we had stopped in the lot of some kind of Wally-like big box, I went in and bought brake cleaner and WD-40 (and some others in category). Then. I lay on the belly board and tried real hard to not shoot myself in the eye. Lots of black stuff dripped into the fan shroud. Between the two mentioned, the spring looked pretty clean (in my mirror) and we continued our journey with pleasant conversation in normal tones.
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] Got Hot- Fan Clutch [message #179582 is a reply to message #179573] |
Wed, 08 August 2012 19:35 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Sort of related:
My Vehicle Speed Sensor (VSS) failed recently and I bought a couple of the
$20 units Hal found on eBay. Today I was out calibrating the cruise
control, VDO speedometer, and EBL EFI for that new VSS's 8000 pulse per
mile output. To reprogram the VDO and EBL after each test run when I
compared the indicators to the GPS, I had to stop and shut down the engine.
During the first of several stops I spent probably 5 minutes beside the
road with the engine off.
When I reviewed the data log from EBL this evening, I discovered some
surprising data. We all know that engine temperatures tend to rise after
engine shutdown. What I didn't realize until this event is just how fast
it happens. The log doesn't record time when the engine's not running so
I'm just guessing that the engine was shut down for 5 minutes. But I'm not
guessing that the engine's temperature rose from 200*F to 239*F in that
time! Wow!
Moving again, I was more concerned about the various speed readings than
engine temperatures, so I didn't notice the high reading; nor did I hear
the fan clutch if it started up. But the data log shows that after engine
start, the temperature immediately began to drop at a rate of about 1*F per
second. That sounds good to me.
My biggest lesson for today. :-)
Ken H.
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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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] Got Hot- Fan Clutch [message #179584 is a reply to message #179582] |
Wed, 08 August 2012 19:58 |
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ljdavick
Messages: 3548
Registered: March 2007
Location: Fremont, CA
Karma: -3
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Senior Member |
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Ken,
I suspect that the rise in temperature is exacerbated by the fact that the temperature sensor is on the top of the engine. If a sensor were in the drain cock of the radiator it would almost certainly be lower. An auxiliary water pump that would run after shut-down, along with an electric fan, would probably cool the puppy in just a few minutes. I wonder what it would take to do such a thing? A water pump would probably take as much current as the fan.
Larry Davick
Fremont, California
A Mystery Machine
'76 (ish) Palm Beach
----- Original Message -----
From: "Ken Henderson" <hend4800@bellsouth.net>
To: gmclist@temp.gmcnet.org
Sent: Wednesday, August 8, 2012 5:35:49 PM
Subject: Re: [GMCnet] Got Hot- Fan Clutch
Sort of related:
My Vehicle Speed Sensor (VSS) failed recently and I bought a couple of the
$20 units Hal found on eBay. Today I was out calibrating the cruise
control, VDO speedometer, and EBL EFI for that new VSS's 8000 pulse per
mile output. To reprogram the VDO and EBL after each test run when I
compared the indicators to the GPS, I had to stop and shut down the engine.
During the first of several stops I spent probably 5 minutes beside the
road with the engine off.
When I reviewed the data log from EBL this evening, I discovered some
surprising data. We all know that engine temperatures tend to rise after
engine shutdown. What I didn't realize until this event is just how fast
it happens. The log doesn't record time when the engine's not running so
I'm just guessing that the engine was shut down for 5 minutes. But I'm not
guessing that the engine's temperature rose from 200*F to 239*F in that
time! Wow!
Moving again, I was more concerned about the various speed readings than
engine temperatures, so I didn't notice the high reading; nor did I hear
the fan clutch if it started up. But the data log shows that after engine
start, the temperature immediately began to drop at a rate of about 1*F per
second. That sounds good to me.
My biggest lesson for today. :-)
Ken H.
__________________________________
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
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| Re: [GMCnet] Got Hot- Fan Clutch [message #179586 is a reply to message #179584] |
Wed, 08 August 2012 20:11 |
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ljdavick
Messages: 3548
Registered: March 2007
Location: Fremont, CA
Karma: -3
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Senior Member |
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It looks like a lot of European cars have electric auxiliary water pumps. Maybe I'll look for one next time I'm at the men's mall. It would be a fun project - the electronics for this could come from the electric fan controller.
Larry Davick
Fremont, California
A Mystery Machine
'76 (ish) Palm Beach
----- Original Message -----
From: "Larry Davick" <ljdavick@comcast.net>
To: gmclist@temp.gmcnet.org
Sent: Wednesday, August 8, 2012 5:58:40 PM
Subject: Re: [GMCnet] Got Hot- Fan Clutch
Ken,
I suspect that the rise in temperature is exacerbated by the fact that the temperature sensor is on the top of the engine. If a sensor were in the drain cock of the radiator it would almost certainly be lower. An auxiliary water pump that would run after shut-down, along with an electric fan, would probably cool the puppy in just a few minutes. I wonder what it would take to do such a thing? A water pump would probably take as much current as the fan.
Larry Davick
Fremont, California
A Mystery Machine
'76 (ish) Palm Beach
----- Original Message -----
From: "Ken Henderson" <hend4800@bellsouth.net>
To: gmclist@temp.gmcnet.org
Sent: Wednesday, August 8, 2012 5:35:49 PM
Subject: Re: [GMCnet] Got Hot- Fan Clutch
Sort of related:
My Vehicle Speed Sensor (VSS) failed recently and I bought a couple of the
$20 units Hal found on eBay. Today I was out calibrating the cruise
control, VDO speedometer, and EBL EFI for that new VSS's 8000 pulse per
mile output. To reprogram the VDO and EBL after each test run when I
compared the indicators to the GPS, I had to stop and shut down the engine.
During the first of several stops I spent probably 5 minutes beside the
road with the engine off.
When I reviewed the data log from EBL this evening, I discovered some
surprising data. We all know that engine temperatures tend to rise after
engine shutdown. What I didn't realize until this event is just how fast
it happens. The log doesn't record time when the engine's not running so
I'm just guessing that the engine was shut down for 5 minutes. But I'm not
guessing that the engine's temperature rose from 200*F to 239*F in that
time! Wow!
Moving again, I was more concerned about the various speed readings than
engine temperatures, so I didn't notice the high reading; nor did I hear
the fan clutch if it started up. But the data log shows that after engine
start, the temperature immediately began to drop at a rate of about 1*F per
second. That sounds good to me.
My biggest lesson for today. :-)
Ken H.
__________________________________
___________________________________________
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
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| Re: [GMCnet] Got Hot- Fan Clutch [message #179588 is a reply to message #179586] |
Wed, 08 August 2012 20:22 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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I do not think you need the pump, Once the coolant in the top of the engine exceeds 180 F. the thermostat opens and the hot coolant will flow to the radiator. The fan will cool it.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Got Hot- Fan Clutch [message #179591 is a reply to message #179584] |
Wed, 08 August 2012 20:24 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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I suspect you're right, it's mostly a redistribution of heat; there's
certainly no energy input to the system with the engine shut down.
IIRC, Arch installed a circulating pump for post-shutdown, and used an
electric radiator fan. I'm sure a water pump would draw much more current
than a fan. I'm not about to do either, but if I were, it would be a
auxiliary radiator fan with thermostatic control Those on the several
Chevy P-30 chassis motorhomes I had were very effective -- usually
preventing the engine driven fan from engaging, and definitely useful in
cooling after shut-down.
Mostly I was surprised at the rates of change in detected temperature.
Almost like the CRV: by the time we get 200 yards from cold start in the
winter, the heater's putting out warm air. Just like a Tokyo taxi. :-)
Ken H.
On Wed, Aug 8, 2012 at 8:58 PM, Larry Davick wrote:
> Ken,
>
> I suspect that the rise in temperature is exacerbated by the fact that the
> temperature sensor is on the top of the engine. If a sensor were in the
> drain cock of the radiator it would almost certainly be lower. An auxiliary
> water pump that would run after shut-down, along with an electric fan,
> would probably cool the puppy in just a few minutes. I wonder what it would
> take to do such a thing? A water pump would probably take as much current
> as the fan.
>
>
>
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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] Got Hot- Fan Clutch [message #179592 is a reply to message #179586] |
Wed, 08 August 2012 20:33 |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
Karma: 0
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Senior Member |
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| ljdavick wrote on Wed, 08 August 2012 18:11 |
It looks like a lot of European cars have electric auxiliary water pumps. Maybe I'll look for one next time I'm at the men's mall. It would be a fun project - the electronics for this could come from the electric fan controller.
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Our twin turbo Audi (2000 A6 2.7t) has a aux water pump mounted under the intake manifold. After engine shutdown, if the engine is hot, it pumps coolant backwards through the turbos.
It seems to be more of a source of leaks in the system than anything else.
These pumps are sometimes referred to as "after run pumps".
Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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