aj007

The needle made it almost to the red before I shut her down. I replaced the thermostat and everything seemed fine until a day when it reached 95 again and the needle ended-up PEGGED before I noticed it. It was probably pegged for about 3-4 minutes I'm guessing.

I can still drive it w/o overheating if I don't use the A/C.

Now, days later, I don't seem to be leaking coolant, which is a relief; maybe my gaskets are ok.

From your experience, is my motor probably damaged from those two overheatings? What kind of overheat-caused damage symptoms should I watch for now? Anything I can check?

2001 GS 430

bruceb58

I would be performing a cylinder leak down test.

Is your fan coming on? Is coolant getting forced into your overflow reservoir?

lexo98

iTrader: (2)

Did you burb the cooling system after you replaced the thermostat? If you have air trapped in the system the fans won't turn on.

Fcdrifter2

iTrader: (2)

look for swelling or splitting on the radiator tanks, oil in the coolant and vice versa. Perform a cylinder leak down test, hopefully not but worst case head gasket is gone.

ksultan78

this. My head gasket blew on my car. same thing you are describing.

akafixture

as others have said do a pressure test. We have aluminum blocks, and very sensitive to heat. Yes, nothing might not be wrong now, but overheating is bad for aluminum. It warps and does other things, sometimes not immediately. Drive it normally and watch everything for a while.

Mr Jokster

iTrader: (8)

My car overheated every day all through spring and summer last year and wouldnt warm up in the mornings throughout winter... No problem on my end But its not like I pegged the needle and drove it for a half hour either. Its very likely nothing is wrong. Its the idiots who dont pay attention and its pegged the whole time they drive that have the problems. Theres more to the idea of 'overheating' and where the needle is reading and whats actually happening to the engine, but I'm too lazy to right it up right now

aj007

Thanks to all! I've be sure to ask for these checks when I finally get it in the shop.

And no, I didn't @lexo98, I did not burb the system. I did read it in the instructions but thought it would be safe to skip it... my gamble.

It only overheats on hot days with the A/C on. What does that suggest?

bruceb58

How often do you change your coolant? I change mine when I change my timing belt at 90K. Speaking of which, I always change my thermostat when I change my water pump at the same time as the timing belt.

I live in CA and even with our 114 degree days last week, the needle stayed dead in the middle.

Like i said before. make sure the fans come on, especially when AC is on.

When I fill my system, I fill it full...turn the heater on full and make sure the overflow container is full. It will burp by itself. Nothing special needed.

aj007

I've barely owned it for a year. Great, it should be burped by now then. The fans come on, but according to the manual, they should speed-up after the coolant is over 200 degrees. Haven't checked that. It didn't overheat last summer. The coolant looks really clean.

The shop said that it could be the water pump, but I'm not clear on how the water pump can fail in such as way as to not be completely broken but only partially <shrug> The level in the reservoir is the same level every morning. I guess checking that coolant is being pumped into the reservoir will check that, eh?

lexo98

iTrader: (2)

Sorry should have said burp. No disrespect to the other poster but don't let it burp by itself. There is a reason your system is not working right. I wouldn't guess at it. I didn't do mine when I didy radiator and after about 10-15 minutes of idling and the needle being in the middle it started to climb quick. I burped the system and never had the problem again.

bruceb58

You know what, I have a GS300 so there is no issue with that engine and burping. I missed the part where the OP has a 430.