Crazy temp gauge...

[mustang347]

I am cruzing around today, enjoying my new found A/C and I glance at my temp gauge, and it is almost pegged!!! I hurry home with it just about in the red and shut it off. I check things out, all seems fine. I start it, and the fans are not on with the needle almost in the red. I turn the A/C on, and the fans start kickin and it sloooowly starts to cool. I go for a drive, and it stays at about 3/4 hot.

I am driving it like an old lady with the A/C on so the fans are running, all nice and slow and its still not cooling much. I start to get pissed, so I start to hammer on it. All of the sudden, it needle drops to half way! Its pointing straight up!! NORMAL??? I drive more, and it swings fast back up to hot!

I get home, and its almost in the red and I turn the A/C off and let it sit for a second. NOW the fans turn on.... That makes sence! For some reason I think the temp gauge is about half way too hot! Anyone else experience this?

Oh yea, is it easy to hook up a mechanical water temp gauge on this car?

 

[TurboSpoolinIns]

UM yeah, it was my thermostat when i experienced that. Try that. it takes a whole 5 minutes and $5.

 

[cmc]

It may be the therostate, did the car smoke at all. When my themostat went, the needle didn't work at all!

 

[mustang347]

Well, when I started the car today (after sitting overnight for at least 9 hours) the needle was PEGGED in the red? Doesnt sound like a thermostat to me.... Does it still sound like one to you guys? Why would it read that I am burning hot when the car was cold and I was only driving it for 30 seconds??? The gauge still moves from OK to hot very fast.

 

[97EclipseGSX]

Just to get the dumb stuff out of the way first, You do have properly mixed and not ancient antifreeze in the car? If so, the fans not kicking on could be one of the coolant temp sesnors. (not sure which one is used for the fans) The thermostat has nothing to do with the fans electronically, but that doesn't mean it couldn't be the cause. I have seen in some cases that the thermostat gets clogged or there isn't enough fluid in the system and the temp sensor doesn't get enough antifreeze to it and it won't read acurately. I guess antifreeze can get hotter than air : ). You said the fans turned on when the a/c was turned on so the motors, fuses and relays should be out of the question.

To be on the safe side I would replace the thermostat like they said, also it's a good idea to get a radiator cap too. They are all cheap and can't hurt to replace if you've never done it. Test the coolant while you are at it and replace if necessary. Coolant should be replaced every 30,000 miles or other year (the green stuff at least). I wouldn't reccommend pushing it with antifreeze it's not worth the risk. Rusted blocks, leaking water pumps and warped heads are examples of things that could happen if the cooling system isn't up to par.

And when your car is overheating try running the heater it will cool the coolant for you, thats how it heats the air that flows through it. The A/C puts more strain on the motor. If it works enough with the heater thats how I would recommend cooling the car.

Racing home when the motor is hot like that is a bad Idea and I wouldn't recommend doing that again. Stop let it cool and try to trouble shoot on the side of the road. Your motor will like you alot better if you treat it right. : )

Good Luck

 

[mustang347]

OK, just so that we are on the same page....

I have been working on cars for over 8 years, and now I am employed with an OEM manufacture designing car parts. I have replaced tons of things in my stang, as well my other cars. Basically, I know my way around cars. I know you are just trying to get the dumb stuff out of the way and are just helping as best you can, but I know how the heat works etc. Dont take this as a flame at you, I know you do not know me, and you were just covering everything starting from the begining.

Oh yea, I did not say I was racing home either... I said I hurried home, meaning no stops, straight there which was less then a mile away when I saw the needle pegged. I pulled over as soon as I saw the needle, and shut the car off. Popped the hood, and everything seemed OK. Then I started it back up, and made my way home as fast as I could, but I was not beating on it.

Ok, now that is out of the way....

The car sat for propably 20 hours in the driveway since I drove it last. I turned the key to RUN this afternoon. First thing I see is the temp gauge needle swing past 12 o'clock and on to about 2. It is about 3/4 of the way to the red. NOW, what is the problem?

I removed the sending wire for a gauge on the thermostat housing and nothing happened. Is it the gauge that is screwed?? If it was the thermostat, it would not show that the car is hot when I turned the car to run.

Its either the gauge or the wireing for the gauge....