My coolant temp shows over 260 on the dash, or as high as it goes..it actually gets stuck there for some reason. I replaced the sensor in the driver side head, when I unplug it and hit the dash or thump the little guage it will fall back below 100 or whatever is at the bottom.. The sensor is new, and my old one did the same thing. Whats the problem? This has happened ever since I installed the new heads.

 

Sounds like the gauge itself died on you.

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88 IROC with cobbled together (not by me)drivetrain, 86 (?) TPI unit on an '83 305,CE subframe connectors, Edelbrock strut tower brace, polygraphite bushings all around...it handles like a dream, but man is it hard to push!!

 

Can I fix it? It still swings around alright, what could be broken with it?

 

I had that same problem with my car. It seems the needle would bounce everytime I started the car. The needle would go beyond its normal range and get stuck on the sheet metal that surrounds the gage. I removed the gage face and clearanced the edge of that metal piece to give the needle some room to move. It has been just fine ever since.

 

I just had the same thing happen to my car. And guess what, it was the replacement sensor!
If you bought it at autozone and the part number is tu-66 then more than likely it may be the part and not the guage.

I replaced my old sensor with the new one and the guage got up to 160° and then it went straight to 260° and stayed there! I took a temp reading from the rad and it was a steady 190°.
Drained the coolant and put in the old sensor and everything was fine.

If BOTH of your sensors have a spade terminal for the wire hook-up then the sensor might be your problem.

If your original sensor has the spark plug type of connection then the old one might have gone kaput and the new one will NOT work, or at least it won't work on a 91 with a 305 tbi.

I was pissed when I had to drain the rad TWICE because of a wrong friggen part!

I don't care who makes it and what they say. I know for a fact that if the sensor has a spade terminal it will not work. (period!)

 

You drained your radiator for that? hahaha.. Sorry..lol.. just a little coolant comes out ;p

And yeah, my new sensor is like that, and the old one isn't.. anyone else have some info on this?

 

No I didn't drain my radiator just for that.

I did a coolant change and a few other things while I was at it.

I also checked the part at pep boys and they wanted twice as much for the same part but different manufacturer. But it still had the spade end on it and I really didn't feel like spending twice as much that might only get me the same results.

I'm going to switch over to mechanical gauges when I find my brain and finally get tired of relying on the stock guages.

(edit)
you might try going down to the junk yard and getting a temp sending unit out of another car. It should not cost that much and it might work.
I think it would be worth a couple fo bucks to see if it fixes it.
If mine ever goes bad, I'm either going with a mechanical guage or getting the part from the junk yard.

[This message has been edited by sunbitz (edited September 05, 2001).]

 

Another FYI. 1989 5.0 tpi was exactly right, it was getting stuck on the side of the sheet metal guage. All I did was bend it up a little more so it bounces back. Works fine with the spade connector.