mikerulzu

iTrader: (2)

First off, my car is a 2002 Z28 with about 45k miles on it.

Tonight, when coming home from hockey, my check gages light came on. It was about 40 degrees out, and I was in 6th gear on the highway going about 75, and the temp needle was up into the red. It would go down for a while, but then spike back up, and did it about 4 times over 10 miles or so. It didn't happen again when I got back to city driving. When I stopped and popped the hood, the fans were running, and I thought I heard something boiling.

I have noticed my fans staying on after getting out of the car for the last couple weeks, but I don't drive very often, and it happens kind of randomly. My car has never showed this before, and I'm guessing it's overheating.

Any suggestions, opinions, or thoughts?

bjamick

iTrader: (31)

Thermostat is sticking it sounds like. You can check it by either getting a new one or throw the one thats in the car in a microwave in some water and watch to see if it opens. It will take a few days to trip the SES light but that is a sign when the fans stay on all the time .

LS6427

iTrader: (2)

More info needed.

Is your coolant level low?

Is the temp needle moving slowly into the red and out of the red, or is the needle jumping quickly left and right, like in a couple seconds?

99% of the time, if the cooling system has no leaks, boiling of coolant means blown head gasket(s). If you heard boiling there is air in the system, how it got there, who knows. The temp needle jumping around quickly could be a bad temp sensor.

Boiling coolant means one thing, and one thing only....you have air in the cooling system. Your temp can go into the red (260*) all day long and it will not boil, as long as its full or close to full and you have the proper amount of anti-freeze in their.


********and DO NOT put a metal T-Stat in the microwave. Boil a pot of water and toss it in and watch to see if it slowly opens, using a temp stick to see the temp*******

mikerulzu

iTrader: (2)

OK, I just got back from a drive after putting some more coolant in. It is now in the "full for cold" range.

The car is maintaining hotter than normal, about halfway between vertical and the hash to the right (I guess that's supposed to be 235, since vertical is 210 and red is 260), and will climb up to 235, and spiked up to about 250 a couple times before coming down within 5 or 10 seconds. I seem to remember straight vertical being the norm before.

How do I bleed to system of air?

LS6427

iTrader: (2)

Well, the only way the temp gauge can move really fast is a bad sensor, or if the t-stat does stick, the coolant gets hot, THEN it opens up quickly letting real cool coolant in fast.

Bleed the system of air first before wasting time or money on anything else.

Start the engine COLD, with the radiator cap off.
Stand there until the t-stat opens. You will see the coolant start to flow at the radiator fill opening. Normally, about 10-15 minutes at idle.
Top off the fluid if it drops down.
Then, wait for the flow to stop. T-stat closes.
Wait again foer the temp to rise and the t-stat opens again and starts to flow.
Top it off again. 2 times should do it.

Thats it.

***But, while you're waiting for thr flow to begin, keep walking back and forth and looking at the temp gauge. If you do have a problem with the t-stat, you don't want to stand there like a dummy while your engine is overheating