Gauge or heat sender unit?

scurvy · #1 (**permalink**) 10-05-2007

My temperature gauge is on the blink. i have tried cleaning the contacts, and the wiring is pretty straightforward and in good condition. I even cleaned the contacts to the unit itself, but to no avail. Could the heat sending unit be shot? I have a Volvo-Penta MD6A, inboard diesel, 10hp, 2-cyl.

If so, are these difficult to replace or fix?

Thanks
Chris

speciald · #2 (**permalink**) 10-05-2007

As the engine warms up dpes the voltage to the guage change? If not its the sender that is bad.

scurvy · #3 (**permalink**) 10-05-2007

Quote:

Originally Posted by speciald

As the engine warms up dpes the voltage to the guage change? If not its the sender that is bad.

No, I don't believe that it does. The needle has not moved the past couple of times we have had it running.

camaraderie · #4 (**permalink**) 10-05-2007

Scurvy...the question is whether the guage is broken or the sender. The sender moves the guage higher by sending increased voltage. You must measure the VOLTAGE at the contacts on the guage with a voltmeter from engine start till it is quite warm. If the voltage goes up...you have a bad guage. If the voltage stays the same...you have a bad sender. This assumes the wiring is good as you say.

scurvy · #5 (**permalink**) 10-05-2007

Quote:

Originally Posted by camaraderie

Scurvy...You must measure the VOLTAGE at the contacts on the guage with a voltmeter from engine start till it is quite warm. If the voltage goes up...you have a bad guage.

Thanks Camaraderie!

I just got a tip on the yahoo groups site that suggested I remove the sending unit and drop it in boiling water for a few minutes. I think I remember reading something that suggested this as well. the gentleman that suggested this said that the sender unit has been working perfectly since.

Worth a try...

Chris

thekeip · #6 (**permalink**) 10-05-2007

The easy (and recommended) way to determine if the problem is the gauge or sender is to simply remove the wire from the sender and touch it to ground. If the gauge pegs, the wiring and the gauge itself are OK...replace the sender. If it doesn't, or barely moves at all, replace the gauge (and / or check wire).

howard Keiper

scurvy · #7 (**permalink**) 10-05-2007

Howard, that seems like the best first step.
Thanks for the input
Chris