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Thermostat maintenance

Do any of you folks ever change your thermostat as a matter of routine maintenance? I’m changing the coolant on both of our daily drivers this weekend and normally do the t-stat also . . . every two years. Overkill? Rocketman

I’ve never done that, I keep my cars 10-14 yrs.

IMHO, whenever you change the coolant you should replace the thermostat. Cheap insurance. I’d probably get a new radiator cap, too.

Because my car is over 16 years old, I removed my thermostat all-together. I also drilled a small hole on the inside of the rad cap to let the pressure off the system. My driving is done at sea level so I’m not troubled by a reduced boiling levels caused by altitude. I also have a switch on the dash so I can control the engine cooling fan.

Everyone said that the alterations would reduce MPG … no change at all. In fact the cabin heater pumps out a lot more heat on cold mornings … go figure.

I figure it’s cheap enough that you might as well do it every time you open up the cooling system. What do they cost, about two bucks?

only caveat to that advice would be where it’s a real pain to remove the thermostat–why pull apart intake manifolds and other parts if there is nothing wrong?

If the t-stat is an easy replacement w/ the hoses off then I’d go for it, but otherwise I’d leave well enough alone.

I change the old style coolant every 2 years and the thermostat every 4 years.

Now with my first car with long life coolant I plan to change the coolant and thermostat at 5 years, which is 1/2 the recommended interval.

The idea of removing the thermostat isn’t to save the $5 it costs.
Heat kills the engines and transmissions and both my engine and transmission have over 200 K on the clock … keeping the system reasonably cool should prolong the life of the major engine components.

I don’t see the reasoning behind trying to re-engineer the cooling system on an engine just because it has reached a certain age. I know people with 30-40 y.o. cars and they still put thermostats in their engines. One time my 88 Accord started boiling over after I shut it off because the rad cap stopped holding pressure. And I’m at sea level too.

“both my engine and transmission have over 200 K on the clock”

That will not impress people with 300-400K on their vehicles and their engines set up to factory spec.

Sorry, thermostats are no longer optional (not that they ever were). Fuel injected, computer controlled engines need the coolant to reach design temps to function correctly. And the cap is not there to address altitude issues, it’s there it increase the boiling point of the coolant. I’d strongly recommend against doing without either the thermostat or cap. If your cars don’t run well or overheat with a thermostat and cap, there’s an engine problem.

You’re wasting your time, texases. Once someone gets an idea like this in his head you’ll never convince him otherwise. He’s a true believer.

I know, I just don’t want others to think that’s a good idea…

That seems like a good choice! My Toyota calls for its “long life” coolant to be changed at 8 years 80,000 miles. I’m planning to do it at 4 years regardless of mileage.

You’re right, I’m a true believer. Many of the problems owners have with their engines are either directly or indirectly related to heat … it just makes sense (to me) to keep the engine cool.
With regards to the statement “Fuel injected, computer controlled engines need the coolant to reach design temps to function correctly”, my engine still operates at the “normal engine operating temperature” … It’s just at the low end of the range.

In fact, this is wrong-headed. An EFI car will run rich if you drive it without a t-stat. The computer will think the engine is constantly cold, and run rich to compensate. Your wasting gas for nothing.

Thermostats seem to have unpredictable lives.  Some will last a week and others will be fine in 20 years.  Buying a new one does not guarantee it will live longer than the one that is already there.  

Overall modern thermostats are long lived reliable parts.

I wish you could hear yourself.
Please do some research on how all the engine operating conditions (A/F mixture, ignition timing) are affected by the operating temperature. Then see if you can come back here and still say you’re right.

On a related note, 35 years ago I was driving an old clunker across the US, and it began to overheat in Arizona. I removed the thermostat until I got to a radiator shop. The shop told me they never remove thermostats because a thermostat is needed to slow the water flow down enough for it to cool off when circulating through the radiator. Without the thermostat, the water flow is too fast to properly dissipate the heat. This was years before computer controls.

I knew it. The statement “it makes sense (to me)” is absolutely correct. You think you know better than all the automotive engineers on the planet. Good for you. As long as you watch the temp gauge like a hawk and switch on the cooling fan when necessary you’ll be good to go. I love these little personal modifications people make to their cars.

Keep 'er cool, buddy, and don’t let anyone talk you out of it. You’re right and the rest of the world is wrong.

I never have, and I’ve kept some of my vehicles for hundreds of thousands of miles. But I also change out the coolant every three or four years and monitor my gages during every drive. I’ve never had an overheat, because the moment the gage starts acting funny I look into it.

Most catastrophes happen because either attention is not paid to the devices we have to provide warning or because the warning is seen but ignored.

Oh, and I also look around. Every time I open the hood, whether it’s to change the oil or to fill the windhield wash, I look around at all the fluids (including the brake fluid level), look for signs of anything abnormal, check the belts, etc. You’d be amazed at what you can catch early If you only look.