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Hey,
Lately Ive been noticing that if I drive my car say...10 miles, shut her off, and leave to go somewhere else, a hour or so later, when I start the car, the temp guage skyrockets and the car dings franticly thinking it's over heating. It goes back down within a minute or so. Whats the deal?

Thats no good.

Bad thermostat or a problem with the temp sensor.
I'm going to go with bad thermostat not opening. Although I wouldn't think it would still be that hot an hour later.

Doesn't do it while you drive for an extended period of time, only when you let it sit?

yeah, I can drive like a maniac with a heat index of 110 outside, and it;s fine, but when I park it, and re-start it after a hour or so, it shoots up then goes down

A theory...
Possible bad radiator cap. It may be not holding enough pressure. This will let the coolant boil at normal operating temp. When it is shut off, it makes an air pocket in the head. Thus the head is heating up faster, until the t'stat opens to let the air out. If the t'stat has a jiggler valve, the air would escape, but possibly not enough due to the coolant flow not being enough, and the overall system pressure not high enough to force it out to the expansion tank.

If it is boiling over bad enough, you would hear it at shut down.

Being that both the cap, and the t'stat/seal are relatively inexpensive, if they are more than 5 years old, I would replace them, and go from there...

just got back from a short drive, I could hear it hissing after I shut it off, I'm taking it into the stealership tommorow am.

When my thermostat went bad on my '05 I got a CEL for it.

no cel here

will hopefully know by end of day, what the issue was. Will post it up here

Sometimes its also a sign of low coolant

They're saying either head gasket or the head itself went bad..... ?

I've never heard of a head going bad and causing overheating issues. I would think the only was a head could go bad is if the mechanical aspect of it (Rockers, lifters, etc.) broke. I think they're trying to play you for a fool to get you to buy a whole new head.

EDIT: I would do the easy things first myself. like Tstat replace, rad cap replace, temp sensor and possible flush, refill and properly burp the system and see if that fixes it.

Kelevra wrote:I've never heard of a head going bad and causing overheating issues. I would think the only was a head could go bad is if the mechanical aspect of it (Rockers, lifters, etc.) broke. I think they're trying to play you for a fool to get you to buy a whole new head.

EDIT: I would do the easy things first myself. like Tstat replace, rad cap replace, temp sensor and possible flush, refill and properly burp the system and see if that fixes it.

you can crack a coolant passage and cause problems the head can "go bad"

If you head gasket is toast you might be getting exhaust gasses in your coolant. Is your coolant reservoir loosing coolant all the time?

Verdict is in. My radiator is clogged, water pump is leaking, and the head gasket is bad. I was quoted $1,700 for parts and labor..... Not doing that LOL! I'm buying a head gasket and having a friend help me install it (he's a mechanic, so you dont need to troll my thread)

ha!

Just be sure to check the head/have it checked for any warping. Spending a few bucks for an engine shop to give it a thorough check beats tearing it down again.

You are prolly saving $1000 replacing everything with a friend's help, so put a little of that into a little insurance that it will be dependable for some time to come.

The chances of it being warped are a bit higher, as the air trapped there lets it get much hotter than it should. The temp gauge will not give the true temp, unless it is submerged in liquid.

Bill,
Thats good to know, thanks!
Now that i've seen how cheap this stuff can be, I may just start looking into building/swaping engines.... >:)

How many miles are on this car..?

140,000 miles

Do you trust the shop that told you all that stuff? I've had to deal with a lot of shady shops so I'm always hesitant to believe what they say. I had one tell me my clutch needed to be replace when it was just the slave cylinder.

This guy is a family friend, and a state trooper, I doubt he's gonna steer me wrong

Bill got it right. Bad radiator cap/thermostat. also, my coolant was the color of coffee....(it had never been flushed)