Cooling System Theory

0xDEADBEEF said:

I found this video. No idea who this guy is or what his credentials are if any, but this jives with my understanding of it (which could be wrong, I'm just a code monkey) and experience.

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AK 99 said:

Ok, I finally had time to sit down and watch this video. I definitely agree with him about several things, but there's a few things he states that I definitely don't agree with, I'll see if I can remember to address them all.

I definitely agree that a 180 stat is typically a great option for any performance car or truck.

I definitely agree that removing a thermostat to fix an overheating issue, or installing a 160 stat will not fix anything and it will potentially make things worse. In that case... there's definitely another issue.

He explains why removing a thermostat will change the flow through the radiator and cause an overheating issue, but this is all based on an inefficient radiator. Let's say there's an efficient radiator in place, he states that the coolant spends less time in the radiator, but he makes absolutely no mention of the fact that the coolant is also spending less time in the block getting hot. He does however mention that "you'll probably get away with it if your radiator is good".

He also states that most factory cooling systems are not efficient enough. I think thousands of factory engineers will disagree with that statement. This is really only true if you are making other significant changes, like physically larger engines or power increases. Horsepower makes heat.

Oh yeah, and while I don't like running a 160 stat (I like heat in the cold weather), it simply does not change the speed of the flow through a radiator... it only changes how soon it starts to flow. The flow when open is just the same as a 195 stat. In his example of an extreme ambient temp scenario, he fails to mention that a 195 stat is typically open all the way or nearly all the way at all times. You need either road speed or a cooling fan to keep the engine from running hot. Typically of course. There's probably some exceptions out there.

In short, until someone can give me actual facts of why I'm incorrect, I'll still stand by the following statement: With a proper cooling system for the application, running a lower temp thermostat or even removing the thermostat altogether will not cause an overheating issue. I'll still consider that one as and old wife's tale. It's right up there with "setting a car battery on concrete will ruin it", lol.

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0xDEADBEEF said:

You're entitled to think whatever you want. I stand by my statements as well. You aren't taking into account the time it takes heat to flow, and I would be very skeptical that radiators have gotten all that much more efficient that they can now do in 1 second what they used to do in 1 minute. (Numbers made up)

I tried and failed to do a better job than GM did, and this was a situation where coolant temps were always over 215, sometimes hitting 230+, and for 25-45 minutes at a time. The thermostat does nothing at the point, and yet removing it was catastrophic.

What actually did make a difference was cutting holes in the hood.

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AK 99 said:

Yep, I can certainly agree to disagree. We've had different experiences and that's perfectly OK.

But again, I've never removed a thermostat with the intent to fix an overheating issue. It has always been a situation where the thermostat is randomly sticking, or just plain sticks closed, then I remove it to keep on going down the road until I get home.

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0xDEADBEEF said:

You're entitled to think whatever you want. I stand by my statements as well. You aren't taking into account the time it takes heat to flow, and I would be very skeptical that radiators have gotten all that much more efficient that they can now do in 1 second what they used to do in 1 minute. (Numbers made up)

I tried and failed to do a better job than GM did, and this was a situation where coolant temps were always over 215, sometimes hitting 230+, and for 25-45 minutes at a time. The thermostat does nothing at the point, and yet removing it was catastrophic.

What actually did make a difference was cutting holes in the hood.

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0xDEADBEEF said:

This all got started when the OP was blowing off the upper radiator hose. Exact same problem that I had with similar causes, and I think I helped him fix his issue. Sometimes too much flow is a bad thing.

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AK 99 said:

So just to be clear, in your situation, you were having issues with it running hot, no matter what you had for a thermostat?

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GrimsterGMC said:

Airflow is just as important as water flow and is sometimes the real culprit. Like having a fan shroud fitted to utilize the whole of the radiator.

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