Thermostat trick...?

[bucket]

"A common misconception is that if coolant flows too quickly through the system, that it will not have time to cool properly. However the cooling system is a closed loop, so if you are keeping the coolant in the radiator longer to allow it to cool, you are also allowing it to stay in the engine longer, which increases coolant temperatures. Coolant in the engine will actually boil away from critical heat areas within the cooling system if not forced through the cooling system at a sufficiently high velocity. This situation is a common cause of so-called "hot spots", which can lead to failures.

Years ago, cars used low pressure radiator caps with upright-style radiators. At high RPM, the water pump pressure would overcome the radiator cap's rating and force coolant out, resulting in an overheated engine. Many enthusiasts mistakenly believed that these situations were caused because the coolant was flowing through the radiator so quickly, that it did not have time to cool. Using restrictors or slowing water pump speed prevented the coolant from being forced out, and allowed the engine to run cooler. However, cars built in the past thirty years have used cross flow radiators that position the radiator cap on the low pressure (suction) side of the system. This type of system does not subject the radiator cap to pressure from the water pump, so it benefits from maximizing coolant flow, not restricting it."

Source:

Stewart Components - High Performance Automotive Cooling

.

we pulled mine out befor i began to look for other answers, and, it did run hotter..220 without, 204 with

 

[TedC]

I know this thread has been focused on LT1s, but here is what I discovered with 180 and 195 thermostats on a stock L98.

Background…
My stock 1989 was not heating up properly, and read the numerous posts and views on what to use. I decided to contact Gorden Killebrew and get his perspective. He suggested using a 180 thermo in the L98 as long as the car is not driven on real cold days and is not required to pass any exhaust pipe emission testing. Anything lower, and the stock ECM cannot manage the engine properly. 180 provides a good balance between engine life (proper oil temps to burn off moisture) and performance (low intake temps). So why did GM use 195? Emissions.

What I discovered…
In goes the 180. I now had consistent heat and discovered a reduction in fan cycling when driving in stop and go city traffic. Then I felt this wasn’t a fair test because the 195 was defective. In goes a new 195. Up went the fan cycling, and so did intake manifold temps and heads (IR measured consistently > 10 degrees hotter). You could feel the heat difference when you popped open the hood after a drive. Back to the 180. Cycling time went down again, and so did the intake temps. L98 had better throttle response when the coolant temps remained below 200 in my opinion (no formal testing). I did not see any change in MPG. I decided to replace the secondary fan switch (not under ECM control) with one that opens up sooner at around 210 degrees. Reprogramming the EPROM (ECM) to engage the primary fan sooner is really a better solution, but the secondary fan (pushes air) enough air to cool even a stationary car. This past summer I drove 650 miles to Bowling Green and Nashville from Buffalo, and even in high humidity > 85 degrees days, fan cycling was infrequent in city traffic. When Fall arrived, the 180 provided plenty of heat with outside temps < 35 degrees. Now, the bright red Vette waits for Spring, while the bright orange snow blower gets most of my attention.

 

[joshwilson3]

.

we pulled mine out befor i began to look for other answers, and, it did run hotter..220 without, 204 with

What do you mean it runs hotter? Sitting at idle? 220 is still in the normal range GM engineered. And was this your 92? See above about running an LT1 without a thermostat, it looks to run hotter cause the coolant bypasses the radiator.

 

[bucket]

What do you mean it runs hotter? Sitting at idle? 220 is still in the normal range GM engineered. And was this your 92? See above about running an LT1 without a thermostat, it looks to run hot cause the coolant bypasses the radiator.

..
whatever....the older american cars ive done this to also ran hotter...?

 

[bucket]

I know this thread has been focused on LT1s, but here is what I discovered with 180 and 195 thermostats on a stock L98.

Background…
My stock 1989 was not heating up properly, and read the numerous posts and views on what to use. I decided to contact Gorden Killebrew and get his perspective. He suggested using a 180 thermo in the L98 as long as the car is not driven on real cold days and is not required to pass any exhaust pipe emission testing. Anything lower, and the stock ECM cannot manage the engine properly. 180 provides a good balance between engine life (proper oil temps to burn off moisture) and performance (low intake temps). So why did GM use 195? Emissions.

What I discovered…
In goes the 180. I now had consistent heat and discovered a reduction in fan cycling when driving in stop and go city traffic. Then I felt this wasn’t a fair test because the 195 was defective. In goes a new 195. Up went the fan cycling, and so did intake manifold temps and heads (IR measured consistently > 10 degrees hotter). You could feel the heat difference when you popped open the hood after a drive. Back to the 180. Cycling time went down again, and so did the intake temps. L98 had better throttle response when the coolant temps remained below 200 in my opinion (no formal testing). I did not see any change in MPG. I decided to replace the secondary fan switch (not under ECM control) with one that opens up sooner at around 210 degrees. Reprogramming the EPROM (ECM) to engage the primary fan sooner is really a better solution, but the secondary fan (pushes air) enough air to cool even a stationary car. This past summer I drove 650 miles to Bowling Green and Nashville from Buffalo, and even in high humidity > 85 degrees days, fan cycling was infrequent in city traffic. When Fall arrived, the 180 provided plenty of heat with outside temps < 35 degrees. Now, the bright red Vette waits for Spring, while the bright orange snow blower gets most of my attention.

....
i have my fan adjusted to come on at 160..
the cars runs 174
the throttle response indicates a stronger mix..
and..horsepower must be up...
cooler is better,
if you run stock 220 degrees and have any kind of failure then you have just bought an engine or at least a head gasket..
with a 160 you have time to deal with it ..LOL

 

[joshwilson3]

I know this thread has been focused on LT1s, but here is what I discovered with 180 and 195 thermostats on a stock L98.

Background…
My stock 1989 was not heating up properly, and read the numerous posts and views on what to use. I decided to contact Gorden Killebrew and get his perspective. He suggested using a 180 thermo in the L98 as long as the car is not driven on real cold days and is not required to pass any exhaust pipe emission testing. Anything lower, and the stock ECM cannot manage the engine properly. 180 provides a good balance between engine life (proper oil temps to burn off moisture) and performance (low intake temps). So why did GM use 195? Emissions.

What I discovered…
In goes the 180. I now had consistent heat and discovered a reduction in fan cycling when driving in stop and go city traffic. Then I felt this wasn’t a fair test because the 195 was defective. In goes a new 195. Up went the fan cycling, and so did intake manifold temps and heads (IR measured consistently > 10 degrees hotter). You could feel the heat difference when you popped open the hood after a drive. Back to the 180. Cycling time went down again, and so did the intake temps. L98 had better throttle response when the coolant temps remained below 200 in my opinion (no formal testing). I did not see any change in MPG. I decided to replace the secondary fan switch (not under ECM control) with one that opens up sooner at around 210 degrees. Reprogramming the EPROM (ECM) to engage the primary fan sooner is really a better solution, but the secondary fan (pushes air) enough air to cool even a stationary car. This past summer I drove 650 miles to Bowling Green and Nashville from Buffalo, and even in high humidity > 85 degrees days, fan cycling was infrequent in city traffic. When Fall arrived, the 180 provided plenty of heat with outside temps < 35 degrees. Now, the bright red Vette waits for Spring, while the bright orange snow blower gets most of my attention.

Yeah, my car runs cooler driving around town in my 195 Robertshaw (Which starts opening at 180) than the OEM type 195 (Which starts opening at 195). Around town and at stop lights, I run 175-180. Obviously if I sit for long periods, the temps will go on up till the fan kicks on.

I do wonder if running a lower temp stat, which lets the engine run cooler driving around might help prevent or delay the headgaskets from failing in the late L98's.

 

[joshwilson3]

....
i have my fan adjusted to come on at 160..
the cars runs 174
the throttle response indicates a stronger mix..
and..horsepower must be up...
cooler is better,
if you run stock 220 degrees and have any kind of failure then you have just bought an engine or at least a head gasket..
with a 160 you have time to deal with it ..LOL

Why do you have your fans set to 160? That is really low for a fan to come on. I'm guessing it runs all the time? Which will burn out fan motors.

If you have an engine failure when you run your engine at 220. Then it was probably gonna happen anyways and would probably need to be fixed no matter what temp you run at.

But I have posed the question if the temps are lower if that might prevent or delay the headgaskets failing. It is just speculation. I do know other factors like galvanic corrosion, headgasket material, and headgasket design have been blamed for the headgasket problems on the L98's. But it does get hot at the back of the block, so running a little cooler might delay it.

 

[joshwilson3]

..
whatever....the older american cars ive done this to also ran hotter...?

Run hotter? Does that mean driving around town or sitting idle for long periods?

And with regards to: "we pulled mine out befor i began to look for other answers, and, it did run hotter..220 without, 204 with"

Was that with your 92 that has an LT1 engine? If so, then that ran hotter cause the thermostat is different than the older engines and needs to be there. You can have engine problems running an LT1 without its correct thermostat. It will also cause problems if you put in an older stat L98 style stat into an LT1 engine.

 

[roger longman]

Hi all, Hey bucket, you're over at La brea ? As I recall a modern(ish) engine is designed to run at 195 - 220F for maximum efficiency. Whilst accepting the argument that L98'S run hotter at the rear, I haven't seen a good point for running below those temperatures. Roger.

 

[bucket]

Hi all, Hey bucket, you're over at La brea ? As I recall a modern(ish) engine is designed to run at 195 - 220F for maximum efficiency. Whilst accepting the argument that L98'S run hotter at the rear, I haven't seen a good point for running below those temperatures. Roger.

..

yes, Wilshire and masselin
i've had thermal issues with this ride since day one,...
i popped an upper radiator hose 100 yards from my parking spot before i got it home.
it was way hot the first day.
no ill effects,
except to my psyche..
then,after replacing the hose and belt and fluid, when it ran 220 (normal) i freaked out and went to work..lol
this is the end of the first day project..,
i can laff about my experience now, but, it will be firmly ingrained in my mind, the next "major" problem i have.
peace, out
steve

 

[joshwilson3]

I just came across this from Mid America. It is a replacement coolant fan switch that automatically adjusts when the fan turns on and off. It says:

"Auto System Kicks Fan(s) On At 200 Degrees And Off At 185"

It looks like it is for 84-91.

www.mamotorworks.com/corvette.html?store=1&keywords=609108

 

[roger longman]

Hi all, If, as has been suggested, the temperature range was set by GM, to pass emissions, how will it pass with lower temperatures ? Roger.

 

[LLC5]

Hi all, If, as has been suggested, the temperature range was set by GM, to pass emissions, how will it pass with lower temperatures ? Roger.

The requirements for federal emissions testing to certify a new vehicle for sale in the U.S. are very stringent and complex. What is required at a local/state level for vehicle tabs is way less stringent. As long as the vehicle can pass a visual inspection, have no codes in the ECU, and go into closed loop, you should be able to pass a state or local emissions test.

 

[roger longman]

Hi LLC5, Thank you. Now back to why would you ? Roger.

 

[Fatsky]

Hello Folks, will be flushing my rad. this wkend. puttin in a new thermstat. Can anyone give guidance on the correct burping procedure. 95 LT1. Thanx kids.

 

[bucket]

i ran with out the ac and played with adjusting the cooling fan at different temps,
i can control the operating temp from 174 up to and beyond 207....and maintain a constant at any setting in between.
thats with a 160 and and an adjustable cooling fan stat

 

[vetteboy86]

Hello Folks, will be flushing my rad. this wkend. puttin in a new thermstat. Can anyone give guidance on the correct burping procedure. 95 LT1. Thanx kids.

Welcome to the forums Fatsky

You may try creating a new thread, better results possibly. Otherwise use the search tool and fine out everyone's advice on how to do this project. I have seen many different suggestions, that have worked for many different people.

Good Luck!!

 

[roger longman]

i ran with out the ac and played with adjusting the cooling fan at different temps,
i can control the operating temp from 174 up to and beyond 207....and maintain a constant at any setting in between.
thats with a 160 and and an adjustable cooling fan stat

Hi Steve, OK. So PLEASE can someone come up with the CORRECT runing temperature for street use ? Roger. ;help

 

[bucket]

hey Roger..
that question wont be solved in our lifetime, unless you know an engine builder that does not work for the Big Three..they all have agendas..i like mine a little cooler, it gives you a little slack time in case of circulation failure(if you blow a hose stuck in traffic with a stock 220 degree running temp you have about 5 seconds before you melt down)and it gives me a noticeable quicker throttle response..operating temp around 180 has been a desirable number since the 50's..even with all this high tech stuff, its still the same basic engine as i was then, air and gas in, apply heat and gas out...hotter is more efficient but cooler is quicker...