OK to remove thermostat?

The engine is designed to run at a specific temperature to achieve the most efficient operation. No thermostat may make it run too cool and you'll be using a lot more gas, which in itself is not good for the engine. Although there are cases where no thermostat will allow the coolant to run thru the radiator too fast and NOT get cooled sufficiently.. The best thing you can do to extend the engine life is change the oil/filter every 3K or so

Will run cooler, gas mileage will might/might not drop a few mpg's and it won't have any heat, but thats all.

No, but it won't do you any good.

The engine will run cooler only when it starts up, when you want it to heat up. It won't run any cooler during long hot drives, when the thermostat would be open anyway.

This will not extend your engine's life, it will only reduce your gas mileage because it will take longer for the engine to come up to temperature.

If the engine is running hot, find out what is causing it to run hot and fix it. If the engine is running hot, taking the thermostat out will not cause it to run any cooler.

--scott

Bad idea.

The engine should be running at design temp. If you run cool the computer can over richen the mixture which will hurt your gas mileage. You can run in to other problems like oil contamination if it doesn't get hot enough to burn off the excess fuel.

Steve B.

With all due respect, this is a myth. There are, on some designs, reasons why removing the thermostat may detract from cooling, but speed of flow through the radiator is definitely not valid.

Yes.

What you are proposing will likely shorten the life of the engine because it will never reach proper operating temperature.

Is this a solution to an overheating problem? If so you should fix the cause of the problem.

Modern thermostats are not bistable like the old ones. It is not just full open or full closed. Modern cooling systems do a good job of holding engine temp at a specific value. However, I agree with the idea of fixing any overheating problem properly. If there is not an overheating problem, don't monkey with it.

I'm not sure what fuel delivery system this car uses, but many injections systems will not enter the "warm" strategies if the temp is too low, which may make it run open loop.

The gas mileage will drop, quite a bit, meaning like about 1/3 if you do that.

Engine wear is higher as you depart from design operating temperature in either direction. If the engine is too cold, metal parts will shrink, clearances will change, wear will increase. And then there's the unburned gas that slips by the rings and dilutes the oil in the crankcase.

Running an engine cooler doesn't extend life. If you measure cylinder wall wear as a function of metal temperature, the wear is actually much higher at say 140 degrees F than it is at 200 degrees F. That is purely a metallurgical phenomenon.

Then there's the whole issue of excessive fuel diluting the engine oil at lower operating temps.

The thermostat is there, in part, to EXTEND engine life.

Just how far back do you have to go to find a bistable thermostat, anyway? My oldest vehicle is a 1949 Plymouth with a 217 cid flathead six, and it has a continuously-regulating thermostat that holds the coolant right at 160 degrees F. Just like a modern system, except about

40 degrees cooler. And I know that Chrysler, at least, was using that system right from the start of the short-skirt six family of engines in the early 1930s, and probably back with the ZSB sixes in use at the start of the Chrysler Corporation in the 20s, for that matter.

We're only talking about a 15 degree difference in temp here, how much will that affect an engine that is capable of starting at below zero and operating at over 200 degrees ?

I would like to know how this clearance change occurs though. I would think that all parts in the engine would shrink when it gets cold. As an example, when the pistons shrink from the cold I would also assume the cylinder bore that houses the piston would also shrink the same amount. Or maybe when the crankshaft shrinks from the cold the main bearing journals, whick surround the crank, would also shrink the same amout. Now, I could be wrong, and if that's the case maybe you could explain why the engine doesn't seize up when it gets hot.

wear will increase. And then there's the

Maybe try a lower pressure Rad Cap. Comments?

What would that do?

That will just let the coolant boil quicker if there is an overheating problem. A higher pressure radiator cap raises the boiling point of the coolant.

Yes.

What you are proposing will likely shorten the life of the engine because it will never reach proper operating temperature.

Is this a solution to an overheating problem? If so you should fix the cause of the problem.

| Not only will the engine be running too cool Define too cool. If an engone is too hot ( torque drops ) in summer, air intake tmprtre will be @ least 40ºC ( ideal ), in summer this is the main tmprtre requirement to maximise torque, though cat convertor may not be hot enough to convert enough gases.

| the enriched fuel mixture Mixture is rich only during open loop when e.g. my O2 sensor reads 0.62 - 0.65 v.

| will cause the catalytic converter to overheat and create a fire hazard. During open loop, c-c is not even hot enough to work well. My c-c never caught fire during open loop ( even when prolonged 3-

4x by removal of thermostat ).

| > Will it harm anything if I remove the therrmostat for the duration of the | > summer? | Yes. I used to remove mine on 2 engines, no damage noticeable. No need now, I found far better ways to cool engines.

| What you are proposing will likely shorten the life of the engine Not in a hot summer.

| because it will never reach proper operating temperature. True only in cold air. In warm / hot air, engine will but slower.