LS1 Cooling
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Joined: Apr 2010
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LS1 Cooling
It is my understanding that the cooling system on my C5 LS1 is a "reverse system". If I understand correctly, the hot water goes into the top of the radiator, cools down going through the radiator, comes out the bottom, and goes into the water pump, through the thermostat. If this is correct, then the thermostat will not let cool water into the engine until it has reached the thermostat temp (in my case, 180 degrees). The water then goes to the heads, then through the block, and back out to the top of the radiator. If this is the case, then the water getting to the temp sensor, will always be hotter than the thermostat temp (in my case, the temp driving highway is 194 degrees). Why has GM designed the system this way? Every other engine I ever worked with has the thermostat on the outgoing side of the engine, not the input. I sure there is some reason that this is more efficient, more consistent, ...... Any thoughts? Thanks
Team Owner
Joined: Mar 2001
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From: small town in S.E Pa. PA
St. Jude Donor '03-'04
What were we thinking?
It cools the cylinder heads before anything else. This helps keep the heads cooler, allowing higher compression ratios and more power production before detonation in the cylinder. I often wonder why so many people want to hang on to the old ways as if they were better even in the face of developing a small block engine that produces 430 HP and gets 30 mpg. Back in the old days a small block chevy 283 solid lifter fuelie would get 10 mpg. There is nothing good about the old days when it comes to automotive technology.
Bill aka ET
Bill aka ET
Last edited by Evil-Twin; Jul 20, 2010 at 11:47 PM.
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You guys should contact GM and correct the engineers who designed the engine, clearly they lack your expertise.
Extract from the SAE paper published by GM:
You may be thinking of the LT1/LT4 engine design, which was reverse-flow.
Extract from the SAE paper published by GM:
The internal engine cooling circuit of the LS1 is arranged in what may be termed "Conventional Flow." Coolant is delivered by the pump to the cylinder case, flowing through the cylinder case, traversing the head gaskets, then through the cylinder heads and exiting the engine. This conventional bottom-up flow maximizes the air and vapor purging capability of the circuit.
You may be thinking of the LT1/LT4 engine design, which was reverse-flow.
Last edited by crainholio; Jul 21, 2010 at 04:22 AM.
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The inlet-side [thermostat] location eliminates thermal cycling common with outlet-side designs.
http://papers.sae.org/970915/
Drifting
Joined: Nov 2005
Posts: 1,320
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From: NW Chicago
St. Jude Donor '12-'13-'14-'15
So what is the inlet and outlet of the radiator? I was under the impression the the top radiator opening is the outlet(cooled water) and bottom the inlet(hot water)
Drifting
Joined: Jun 2010
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From: Harrisburg Pa.
hot coolant from engine to top radiator inlet, thru radiator to cool, out the bottom and back thru the engine. top is outlet for the engine and inlet for the radiator. bottom is outlet for the radiator and inlet for the engine. top=hot, bottom=cool.
Drifting
Joined: Jan 2008
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From: Florida
St. Jude Donor '09
The C-5 radiator is cross-flow single pass design, hot and cold sides are side to side, not top to bottom. You are correct about the flow path.
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Drifting
Joined: Jun 2010
Posts: 1,434
Likes: 2
From: Harrisburg Pa.
i was actually trying to describe which was the enter/exit of the radiator as to hot/cool, not trying to imply which part of the radiator itself was hot/cool.
Drifting
Joined: Nov 2005
Posts: 1,320
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From: NW Chicago
St. Jude Donor '12-'13-'14-'15
All good info thanks guys. The reason i thought it was the opposite is my liquid oil cooler is connected between the water pump and the top inlet of the radiator. Which meens its the hotter water is cooling the oil, I think it would make sence to have it between the bottom outlet and the water pump, cooler water. I have to check this out under the hood , maybe its more of a space and routing issue and that is why it is on top. The cooler was on the car when I bought it and still learning about it and the car.
