Coolant gauge help need fixed

[denno]

Just purchased a 73 lwb chevy and the coolant temp gauge stays pegged on the hot side. Is there any way to fix this? Any help would be greatly appreciated.

[mhicks]

Sounds like the sensor is bad. That is the same thing it will do if you touch the wire that goeas to the sensor to the block.

[Slonaker]

Mine did that when the green wire going to the sensor melted and touched the valve cover. It bounced like it was posessed when I would hit bumps.

Slonaker

[denno]

So If for example the coolant temp sender wire was grounded that would cause the gauge to read way over hot.

[79BIG10]

Originally Posted by denno

So If for example the coolant temp sender wire was grounded that would cause the gauge to read way over hot.

Right. From the driver side firewall look for a single green wire coming out of it to the engine block. It will have a plastic yellowish clip on the end. This connects to the sensor in the head between the exhaust manifolds.

[Slonaker]

Originally Posted by 79BIG10

Right. From the driver side firewall look for a single green wire coming out of it to the engine block. It will have a plastic yellowish clip on the end. This connects to the sensor in the head between the exhaust manifolds.

Mine just has a spade connector, but look for the green wire on the driver's side of the engine, near the front.

Slonaker

[Bad Karma]

How far past the last line will it go if the sender or wire grounds out? My gauge is pointing at the 4 o'clock position as of last week and doesn't move at all. I figured the gauge must have broken to go that far and stay there...

[Slonaker]

Mine pegged out.

Slonaker

[79BIG10]

Originally Posted by Bad Karma

How far past the last line will it go if the sender or wire grounds out? My gauge is pointing at the 4 o'clock position as of last week and doesn't move at all. I figured the gauge must have broken to go that far and stay there...

Does it move back to lowest temp possible when you turn the key to off? If so then you can almost be sure it's a short.

[denno]

It just stays pegged on the hot side.

[jimmmie '79 Cheyenne]

Had the same prob on mine a couple months ago. Got flustered trying to trace the wire and a buddy at work had an extra set of gauges. Swapped out the temp gauge and all was well. Did a little troubleshooting on the gauge and the resisitor on the back was bad. A place called "fix-a-gauge" has the part for about $8 or if someone else knows the size, you can get it at radio shack. Good Luck...