Engin Heat
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Intermediate
Joined: Nov 2005
Posts: 36
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From: Boonville Missouri
Engin Heat
I have a 73 L-48. In idle trafic it runs up to The high side of 210 degrees. I worry that it could go even higher. As soon as I get on the open road the temp. drops to a more normal degree. Installed a new fan clutch, 160 degree thermostat, The radiator is new. I am thinking of electric fans or fan. Even thought of welding the fan clutch solid. Can anyone give me some advise.
Burning Brakes
Joined: Aug 2005
Posts: 1,126
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From: Hudson Falls, N.Y. 76 Vette Modified L-48
Personally, I think 210 is too high...my 76 L-48 runs at 190, no matter how hot the ambient air temp gets to (it does get into the 100's even here in upstate NY)....for the sake of your sanity, why not pull the thermostat right out completely and see what happens temp-wise...if you run cool, it's the thermostat causing probs...I mean before dropping a ton of dough on electric fans....easy first, expensive later...just my 2 cents
Melting Slicks
Joined: May 1999
Posts: 2,897
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From: Moon Township PA
I know that modern cars run that hot on purpose. I believe that your original thermostat was a 190 degree unit so I doubt that GM ever intended for it to run at 210. As others have stated, check your radiator seals to see if you have the foam seals. A good place to start is with Dr. Rebuild's catalog. Not only do his great photos show where the seals go, he sells them. Real high quality stuff.
Then, make sure that your water pump is up to snuff. IIRC, there is a test for the water pump, measuring its output over a give period of time. Of hand, I don't remember what it is but I will see if I can find it.
Gary
Then, make sure that your water pump is up to snuff. IIRC, there is a test for the water pump, measuring its output over a give period of time. Of hand, I don't remember what it is but I will see if I can find it.
Gary
Race Director
Joined: Nov 2000
Posts: 11,872
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From: Waterloo ontario Canada
Originally Posted by GaryS
Then, make sure that your water pump is up to snuff. IIRC, there is a test for the water pump, measuring its output over a give period of time. Of hand, I don't remember what it is but I will see if I can find it.
Gary
Gary
Race Director
Joined: Mar 2001
Posts: 11,322
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From: Living in the Hartland
Other than the bearing and seal what else could be wrong with it? Unless the impeler corrodes and the vains rust away I would think it would pump out the same gal/hr (or min not sure on the output rating) over the entire life of the pump
If the clutch is thermal maybe the temp engage point is around 210 so it does not turn 1:1, the shroud seal would be a good starting point. Check your timing, too low and the eng will run hot, I run the vac adv on unported/manifold vac to bring the timing up at idle and it does bring the temp down a touch on hot days compared to ported
If the clutch is thermal maybe the temp engage point is around 210 so it does not turn 1:1, the shroud seal would be a good starting point. Check your timing, too low and the eng will run hot, I run the vac adv on unported/manifold vac to bring the timing up at idle and it does bring the temp down a touch on hot days compared to ported
Last edited by Fevre; Apr 22, 2006 at 09:16 AM.
Melting Slicks
Joined: May 1999
Posts: 2,897
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From: Moon Township PA
Originally Posted by norvalwilhelm
Gary how would you go about measuring the water pump output???
Well, I did qualify it by saying IIRC, as in, if I remember correctly.
I can not find anything in my GM manual but I am still looking.
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Advanced
Joined: Apr 2006
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From: New London NC
Originally Posted by norvalwilhelm
Gary how would you go about measuring the water pump output???
You could try my technique. Leave the radiator cap off and run the engine for a minute and watch a beautiful, green gyser shoot out. Duurr
! Not my finest moment.
Le Mans Master
Joined: Aug 2000
Posts: 6,273
Likes: 14
From: Austin TX
Make sure that your fan is installed properly. When I bought my 71, the fan was installed backwards and I had the same problem you are describing.
All the seals on the back side of the radiator must be in place or air will be pulled around the edges of the fan shroud rather than through the radiator.
Flo Kooler offers a round disk that can be riveted to the impeller of your water pump that will greatly improve its efficiency.
New design water pumps from Stewart, Edelbrock, Moroso have different internal design that flows more efficiently.
All the seals on the back side of the radiator must be in place or air will be pulled around the edges of the fan shroud rather than through the radiator.
Flo Kooler offers a round disk that can be riveted to the impeller of your water pump that will greatly improve its efficiency.
New design water pumps from Stewart, Edelbrock, Moroso have different internal design that flows more efficiently.
Race Director
Joined: Oct 2002
Posts: 12,065
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From: Smalltownville Michigan
Cruise-In 5, 6 & 10 Veteran
St. Jude Donor '09
Originally Posted by chevylit
Be sure ALL of the radiator foam seals are present and in good
shape,without them the fan will not pull the air through the radiator.
shape,without them the fan will not pull the air through the radiator.
ya beat me to it! those little foamy thingys are super critical to cooling!