AaronE

Hey folks, I know there are a bunch of overheating threads, but hopefully someone can suggest an approach here.

It's overheating, CEL comes on, it's boiling over (though the cap is good), it's filled, and both big water hoses are hot. Not surprisingly, the heater blows cold. However, I had to continue driving it for a while and noticed that every now and again, the heater would blow warm and the temperature gauge would drop 2-3 ticks. This only happened twice, and only lasted for about 10 seconds.

In the past few weeks, I haven't been using the car. Prior to that, I now remember that the heater was flakey and required the car to be moving for the auto climate control to turn the heater fan on.

So, the question is, thermostat or water pump?

If it's thermostat, where is it? If it's the pump, how hard is it to replace? I'm at work (about to go to sleep on the couch) which was where I was closest when I noticed the CEL so I'm a little tool-shy, but we'll see what I can do in the morning.

Thanks in advance!
-Aaron

Lexiss_sc430

iTrader: (2)

If the radiator and hoses are hot and the heater blows cold then you would think it’s your thermostat..

But here’s the thing that’s weird, a thermostat is suppose to stay closed while the car is cold and let the water already in the block circulate and heat the engine up quickly... once the temperature reaches they predetermined limit of the thermostat it will open up and let the water from your radiator and lines flow thru.... so technically if the radiator is hot and the car still blows cold air.... it might even be your temp gauge....

So your sure the radiator and over fill tanks are full, bc the heater core gets bypassed when there is not enough water in the system...

If it was your water pump and if the impellers were damaged or worn the problem would be a consistent one… it would not go away after a few seconds or minutes so I don’t think that is your problem…

Best thing I can think of is doing a whole flush of your system.. I mean a through one and then see how things go....

Hope this helps

bigmalik00

yep....thermostat....please don't waste your time with an aftermarket. A lexus one is about $40. If I would have brought a factory one I would have saved about $200 on useless estimates and 250 on bodywork and paint. check all the hoses from the reservoir to make sure they aren't clogged. A shop did a flush but didn't take off the hoses and the sludge was clogging up the hoses.I cleaned them out with a wire hanger.

Tammy

I'm afraid to suggest the radiator needs replacing.

AaronE

Thanks for the replies folks! I took out the thermostat and it does seem to open up in boiling water (that I had microwaved in a paper coffee cup). The temperature gauge is certainly correct, I had lots of steam coming out.

The last time I drove the car, I did notice that it left a relatively large puddle of what looked to be very thin motor oil, and it's done the same thing now. I had attributed it to an empty quart bottle of oil that was upside down in the bumper, but that's obviously not the case this time. Perhaps it's really coolant that's a touch brown? I'm gonna see if without the thermostat I can make it the 1/2 hour home. I suppose then I'll try and flush out the system. Any pointers?

Wish me luck!

Thanks again,
-Aaron

AaronE

Well, Tammy was right, even with me being wrong in my description. My radiator is cracked. It's broken in at least two places at the top (in the plastic) and probably elsewhere too. In my description, I mentioned that I had coolant in there, but... I lied.

Who knew that when the resevoir is full, the system could still take 10 freakin' liters! So, since I didn't happen to have a 17mm socket (whose idea was it to make a system that you have to fill from a bolt!) I took the top hose off and filled it directly into the block. It lasted about 15 minutes into the drive with the needle perfectly at center until it started to climb to the top. I pulled over, took the top hose off again, and poured another 10 liters in. Two more times over the 1/2 hour home I filled it up, but it made it.

So, I'm hoping that it's just boiling off / leaking out and that when I replace the radiator, everything will be fine and the pump will be okay. Since when there is water, it keeps a perfect constant temperature, I think the pump is working. We'll see...

Thanks everyone!
-Aaron

CleanCL

my experience with overheating and this car, if one thing goes, the others will go to. my thermostat, overflow tank, radiator cap, and what i now think is the radiator and water pump are on their way out too. just be careful. for the cost, i'd replace the thermostat, it's so cheap.