curvewrecker

My 66 Toronado temp gauge acts weird. When driving it flutters between normal and high, but when I stop the car it goes to the normal range and stays there. When I start moving it begins to flutter again. Do I need a new sending unit? Do I have a bad ground somewhere? Has anyone else experienced this, and if so what did you do to correct it?

It makes me incredibly nervous, I don't want to risk overheating.

Thanks,
John

oldsmobilejim

Did you just do some work that including draining coolant, air in the system? If you pull your wire from sensor what happens, should go to cold? How does the gauge act with initial start up, is it a steady climb?

oldsmobilejim

To much pipe dope or tape on sensor threads, causing bad ground?
Cheapest first replace sensor if no change your down to two alternatives, wire or gauge.
Just had my gauge cluster tuned up works great reasonable price and turn around time.
I recommend Red line gauge and clock repair.
Hope this helps, keep in touch with outcome...

curvewrecker

Initial startup slowly warms up. Flutters when in motion. I recently replaced my Heater control valve and used the occasion to flush and replace coolant, but it was doing it previously too. I'm planning on replacing the sending unit just because they are inexpensive, but wanted to know if anyone else had experienced this.

droldsmorland

You have to troubleshoot vs replacing parts.
Heres a good video on the basics.


I'd also suggest investing in a set of good quality aftermarket gauges.
I like to see specific readings from a gauge, not approximate values.

Stewart Warner is what Id recommend
https://www.stewartwarner.com/.

rocketscientis

Let us not Overlook the wonderful pin connectors that transfer electricity intermittently from the wiring harness to your gauge you most likely suspect can tell you how fix yours or have one repaired I can swap you

curvewrecker

Thanks for the great video. I will do some troubleshooting and see what its doing. I really don't want to install aftermarket gauges. I've installed them in many cars over the years, but I don't want to in this case, I want to keep it looking original.

If it comes to the pin connectors I will definitely ask Rocketscientis for more help.

Koda

You can run one temporarily.

curvewrecker

You're absolutely right, but my father taught me "Nothing is as permanent as something temporary."

ETA: I installed aftermarket mechanical gauges in my last 66 Toronado in the ashtray. Hidden when I wanted them, visible when needed. I still don't want to put them into my low mileage survivor car.

Koda

I taped one under my dash on my Chevy for years, then fixed the problem, then removed it. It is important you have another gauge, either instead of, or in parallel to, the questionable one so you can get accurate data.

curvewrecker

I added an aftermarket temp gauge and it was better but still fluttered. Once I replaced the missing ground strap between the engine and chassis things went back to normal!

Whoohoo!