Temp gauge blues

[krs09]

I took a nice drive this weekend and after driving for a bit I looked over to the temp gauge and it's reading " 6'oclock" totally dead. When I first got the car I noticed the fans ran continuously, after a good check I found out the Po jumped the wire at the otterstat and plugged the pipe where the sensor sits. Many moons later I had new cooling fans installed (dpnw) , New otterstat, New pipe and everything was great for months and now this.. wtf. Any ideas?

[DMCMW Dave]

I took a nice drive this weekend and after driving for a bit I looked over to the temp gauge and it's reading " 6'oclock" totally dead. When I first got the car I noticed the fans ran continuously, after a good check I found out the Po jumped the wire at the otterstat and plugged the pipe where the sensor sits. Many moons later I had new cooling fans installed (dpnw) , New otterstat, New pipe and everything was great for months and now this.. wtf. Any ideas?

This is gonna sound weird but bear with me. Slap the left side of the binnacle with your hand a few times and the needle will jump to the normal position.

This is typically indicative of a poor ground somewhere causing a reverse voltage spike when you shut off the car with all the accessories running. You can usually avoid it if you turn everything (aircon, heater, radio, lights etc) off before you switch the key off.

[SS Spoiler]

Funny Don Steger did this to my car at a tech session in Missouri back in 1988.

[David T]

Funny Don Steger did this to my car at a tech session in Missouri back in 1988.

The operation of the cooling fans is not directly connected to the temp gauge. Two independent systems affected by the temperature of the motor. Also check the level of coolant. If it gets too low the gauge can't measure the temperature.

[DMCMW Dave]

Funny Don Steger did this to my car at a tech session in Missouri back in 1988.

He showed this to me circa 1998.Not a new trick by any means! I figured out the relationship between this issue and bad grounds much later (in my case the bulkhead ground point).

If it gets too low the gauge can't measure the temperature.

If the coolant is too low the temp gauge will typically read very high since it's reading steam rather than hot water.

[mluder]

I used to have the same problem with my temp gauge... A bad ground (the main one behind the rear bulkhead) would cause the needle to jump around when I started the car and it would often pin itself in the 6:00 position. A tap to the side of the binnacle would often dislodge it. Just be careful you don't hit too hard if you have an original binnacle. the covering can be fragile after 30 years and you could crack it.

Cheers
Steven

[krs09]

After smacking the dash around it did move! it shot straight up to "12 o'clock" and stuck.. So I take a lil spin to the store and after driving about 10min I look down and sure enough it looks to be working again, like magic.... So what was it? Bad ground? In the dash I guess? I replaced my tach and cleaned the whole dash out and cleaned the bulbs and so far everything was great. Guess not.

[Bitsyncmaster]

After smacking the dash around it did move! it shot straight up to "12 o'clock" and stuck.. So I take a lil spin to the store and after driving about 10min I look down and sure enough it looks to be working again, like magic.... So what was it? Bad ground? In the dash I guess? I replaced my tach and cleaned the whole dash out and cleaned the bulbs and so far everything was great. Guess not.

I had an intermittent temp gauge and it was fixed by just removing and reinstalling the bulk head connectors.

Our gauges see to stick if they move to an extreme end of the scale.

[mluder]

Bad ground? In the dash I guess?

Not necessarily in the dash... Could be any number of the ground locations. Mine was behind the rear bulkhead.

Cheers
Steve

[krs09]

I had an intermittent temp gauge and it was fixed by just removing and reinstalling the bulk head connectors.

Our gauges see to stick if they move to an extreme end of the scale.

Just pull all the connectors out, maybe a little cleaner and dieletric grease? Every one or what color?