Any damages from overcooling engine for few weeks?

[DxElite]

I'm 99.9% certain that the thermostat is stuck open.
The car has been running at about 1/3 of the temp gauge when speed is over 30MPH and just under 1/2 (normal) temp gauge when I'm stuck in slow traffic.
85% of my commute is in ~30MPH highway traffic and the rest is at city speeds.

It's been about 10 days since it started running overcooled, everything is running normal, and I haven't used the heater since it started. I'm also driving more "normal" and accelerating slower.
I've tried researching online if there were any associated damage caused by overcooling, but only found that there is an increased chance of more wearing with high sulfuric fuel.

I planned to do the timing service over summer break and was thinking I could wait to replace the thermostat until then.
I was thinking that when it gets hotter here in Houston in a few weeks, it'd start to run warmer.

Aside from poor efficiency and fuel economy, and the noticeable power loss,
Will there be any damage caused by running cool for a few more weeks/months?

2000 Camry 5SFE with approx. 87,000 miles running on 3 weeks old Mobil 0W-30 oil with cold air intake.

[uibalnme]

I doubt it. Better overcooled, than overheated. The only thing that will suffer will be your fuel economy, since the ECU will be constantly spraying more fuel to warm up the engine.

[Mike Gerber]

Your cat converter will suffer too. The engine is running richer when not at normal operating temperature. The engine is probably unable to burn all the fuel that is injected in to the cylinders. Some of that unburned fuel is passing out the exhaust valves and through the exhaust system; that includes the cat converter. If it were my car, I would change the thermostat now.

Mike

[AlmightyCamry777]

Yes overcooling the engine in Houston climate for a while is not going to hurt it. HOWEVER - i had another car where this happened, and since it was over-cooling, i didn't worry about it, and ignored the problem. Until one day the damn defective thermostat stuck CLOSED...that cost me an engine ($1500 for a used engine) when i ignored the temp gauge.

Changing the thermostat on the 4 is easy, and cheap, i'd change it now, for the above reason.

[73sport]

Dx,
Here's another thread on the same if you hadn't noticed. DIY: 1mz thermostat
#19, & #21.

And this one:
Engine never gets warm?



This is nitpicking but . .

Originally Posted by uibalnme

. . . . since the ECU will be constantly spraying more fuel to warm up the engine.

It may add more fuel depending on the actual temp. If it does treat it like a "cold start on a 30degree day" its to make it run smoother and reduce the chance of stalling. This is running the engine rich will cool the engine (too much fuel). While running it lean (not enough fuel) tends to make them run hotter.

As stated, its hard on the cat and if left that way could result in emissions failure, repair bills, ect. Go for drive. Pull over safely off the road and stick your hand near the cat. If roasting hot (above normal, like melting surrounding plastic), it should fixed ASAP. The cat is trying to burn that fuel that didn't get burned in the combustion chamber.

Just for clarification. . .

[carsrus]

I ran a car for two years without knowing the thermostat was stuck open..... no problems. The cat isnt gonna have any problems. I also drove around the same car with a bad o2 sensor for 9 months. No catalytic converter damage whatsoever. More fuel = greater rpm at idle aka the cars burning the fuel and its not being dumped into the cat.

Its not gonna do anything especially in texas where you guys are what like in the 50's 60's now?

The thermostat doesnt do much if its warm outside. The car should peg off the cold no problem if its 60 degrees it just wont hit the middle.

[DxElite]

Thanks everyone for their replies.

After considering all the replies, I've decided to play it safe and replace the thermostat sooner than summer break.

Thanks again everyone.