C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Running Hot, Radiator Not Clogged

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Old Dec 11, 2009 | 02:30 PM
  #21  
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[QUOTE=Driver84;1572397292]The weather is now much cooler and the car still runs consistently and significantly hotter.

I should have mentioned before that my car is running a 160 degree thermostat and I believe his is a 174(?) unit off the top of my head.

QUOTE]




First, do both cars have t-stats designed for the LT1? It is different then a standard SBC t-stat. Personally, I have never seen them in anything except the factory 180 degree and aftermarket 160 degree versions.

Also, I know you said it is consistant, but not meaning to but the temp. difference is the same at idle, cruise, or highway speeds? Just trying to eliminate a fan issue.

And is it possible that your friends computer has been reprogammed for the fans to come on earlier making it run cooler?

What are the tempatures you are seeing anyways?
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Old Dec 11, 2009 | 02:34 PM
  #22  
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wanted to add this link.

http://www.lt1tips.com/hypertech-lt1-thermostat.html


If you notice the picture on the box is a standard SBC t-stat, But the actual t-stat on top of the box is a LT1 style. Its longer and has a disc on the bottom.
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Old Dec 11, 2009 | 04:01 PM
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Originally Posted by pianoguy
It's the brass doohickey on the inlet of the water pump:

If you did not bleed all of the air out with the engine running at op temp with the t/stat open then you are very likely to have problems.
The LT1/4s are very sensitive to trapped air.
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Old Dec 12, 2009 | 11:47 AM
  #24  
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Originally Posted by Driver84
I have been away for awhile, but now I am back...The weather is now much cooler and the car still runs consistently and significantly hotter.

I should have mentioned before that my car is running a 160 degree thermostat and I believe his is a 174(?) unit off the top of my head.

I think I will install a 160 in his to try and get a more linear comparison. I will also have a look at the cap.

As to answer a previous question: in September the Opti went out. It was a crappy aftermarket unit that had been replaced along with the water pump a year before. The pump was inspected and reinstalled along with a new Opti.
You have still not answered the question if you have purged or burped the cooling system....

Change out all the components if you like, but until the system is properly purged of air, the problem will not go away.

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Old Dec 12, 2009 | 12:21 PM
  #25  
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Yes, the system has been burped and purged.
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Old Dec 12, 2009 | 03:31 PM
  #26  
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Originally Posted by Driver84
My friend and I both have LT4's and drive both of them daily.

My car (the black one) has had the radiator out of it recently so it could be thoroughly cleaned. His car (the red one) has had the radiator replaced with a brand new OEM unit recently.

His car is running at least 20 degrees hotter than mine. The water pump is not leaking, there are no coolant puddles on the ground below the car and (as previously stated) the radiator is not clogged and is brand new.

Any thoughts / ideas on what is going on?
It's possible (assuming you haven't owned yours its entire life) that the previous owner may have had the PCM programmed to turn the cooling fans on earlier then the factory settings. What temp is your friends running at ?
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Old Dec 13, 2009 | 10:48 AM
  #27  
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Did you examine the expansion tank where the little hose fittings go in for looseness ?
The tanks are getting old and those brass nipples are easily broke loose from the plastic.
That will keep the system from getting 15 or 16 lb's pressure.
Cooler thermostat will fool your computer and it will add or subtract fuel and air for poor mileage or performance .
The computer uses temps from intake and cooling system in it's calculations for mixture .
LT engines are designed to run hotter than normal to better burn the modern POS fuel .
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Old Dec 14, 2009 | 07:52 AM
  #28  
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Just FYI

My '95 LT1 was running hot when I bought it this summer. It turned out to be a blown head gasket.
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Old Dec 14, 2009 | 08:31 AM
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Don't waste your time with a cooler thermostat. All that is going to do is open earlier, once open it won't make any difference. You have something else going on.
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Old Dec 14, 2009 | 01:29 PM
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Originally Posted by fevest
Don't waste your time with a cooler thermostat. All that is going to do is open earlier, once open it won't make any difference. You have something else going on.
Spoken like someone who has no technical/engineering experience/background...
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Old Dec 14, 2009 | 02:22 PM
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Originally Posted by Driver84
Spoken like someone who has no technical/engineering experience/background...
Can you explain how a cooler thermostat is going to make your car run cooler?

A thermostat has very little effect on the final operating temperature of your engine.
It will allow it to warm up slower or faster though, based on the temperature that it opens.
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Old Dec 15, 2009 | 06:34 AM
  #32  
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Originally Posted by fevest
Don't waste your time with a cooler thermostat. All that is going to do is open earlier, once open it won't make any difference. You have something else going on.
Spoken like someone who KNOWS what effect programming/PCM and the cooling fans have on operating temps.
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Old Dec 15, 2009 | 03:10 PM
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Originally Posted by Driver84
Spoken like someone who has no technical/engineering experience/background...
Huh?

Can you please explain how a 160 degree thermostat will cause an engine that is overheating to operate at lower temps then?

A lower degree thermostat means that it opens at a lower temp. So if you're running in the 200's wtf is a 160 thermostat going to do if you don't make other changes?

Don't be an ***...

Last edited by Atari; Dec 15, 2009 at 03:13 PM.
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Old Dec 15, 2009 | 08:01 PM
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I found that flushing the radiator does not really clean out the single row stock radiator. The best way to do it is pull it, take it to a radiator shop and they will remove one of the plastic side tanks and use pipe cleaner type brushes to clean them out. They will then re-seal the side cap.

Considering NOS radiators can be had for ~100 I just replaced mine. Temperatures dropped 15-20 degree's. Fan rarely goes on now at 228 unless sitting in bad traffic for long periods of time.

On mine I also noticed that before I replaced it, even with regular vacuum cleaner debries cleaned out, when the fan would go on (228 OR turning on the AC) the temp would not actually go down...it would just steady out or go up slower. After the replacement when the fan goes on the temp actually drops.

-D
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