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Factory Temp Gauge Questions

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4.6K views 9 replies 5 participants last post by  Ags290  
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#1 · (Edited)
Last night on a cold start the temp gauge on my son's 64.5 6cyl. went to full hot after idling for about 1 minute. We have owned the car for about 9 months and no history of cooling system issues. He called in a panic and I told him to turn the car off and I would come check it for him. He is a new driver (16) and I was impressed that he was actually watching his gauges.

I got to the car about 10 minutes after he called and checked:
1) The Radiator (barely warm to the touch)
2) The Water Pump Belt (no issues, replaced recently)
3) The Upper Radiator Hose (soft, not under pressure)
4) The Coolant Level (radiator was full)

I had him start the car and the gauge was at about the midway point. I then unplugged the temperature sending unit to check the connection. It was tight. When I plugged the sending unit back in, the gauge went to just off of cold where it should have been. I wiggled the wire around and looked for chaffed insulation and didn't find issues, the gauge stayed solid and after about 5 minutes I had him drive home and I followed.

I checked the car again this morning before I left for work and the gauge was reading cold on start up and slowly came up to temperature.

Now for the questions...

1) Where should I start in trying to diagnose this intermittent issue without throwing a bunch of parts at the car?
2) If the internal voltage regulator on the back of the cluster acts up will it only effect 1 gauge? (fuel gauge was fine withe the normal needle "float")
3) Are all of the replacement temperature sending units as "junkie" as I have lead to believe?

As always any help is appreciated for this pit crew Dad.

Kevin
 
#4 ·
If you don't get a pegged gauge with the key "ON" and wiggling/pulling the wire and harness, then I'd replace the sender.

PS: Don't leave the key on for more than a minute unless you disconnect the coil+ wire to avoid overheating the coil or burning the points.
 
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#5 ·
Bartl,

That was where is was at last night. I pulled and wiggled on the wire to the sending unit with the car running until it came up to temp for the fast idle kickdown and the gauge never fluctuated like it had a bad wire grounding. The temp sensor looks like a easy replacement. I really feel like the wiring is OK after messing with it. My biggest question is about the voltage regulator on the back of the cluster. When it starts acting up will it effect a single gauge or both?
 
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#8 ·
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#9 ·
Instead of troubleshooting & repairing your stock gauge/sender, consider an aftermarket mechanical temperature gauge.

Only $20 at Autozone. Plus another $20 for the mounting cup.


But knowing what I know now, I'd get an Autometer 2607. Range is more appropriate. And it'd match my tach. But costs more than the Equus.
 
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#10 ·
V8 Junkie,

The care and feeding of ponies page is just what I needed to get headed in the right direction. I had searched on this forum and didnt see what I was looking for, I really appreciate the lead. It was dark by the time I got home so no work on the car tonight. Tomorrow is another day. Thanks Again
 
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