Oil pressure gauge goes to zero

[Bleep Bleep]

Oil pressure gauge reads normally each time when the engine is started - cold and at temp. Reads pressures for a few minutes, and readings in normal range.

After a few minutes gauge goes to zero and stays there. Put a new sending unit in today. No change. Interestingly, the unit came with some type of white thread sealer? Could it be a poor ground issue? Should it be removed? Or just a **** sender?

Has anyone had the similar issue? ‘70 charger U code w/rallye dash gauges if that’s relevant?

Ideas where to look next? Thanks.

 

[dadsbee]

Stop f'n around and screw in a mechanical gauge fitting.

 

[Bleep Bleep]

Yea. I don’t like the idea of a separate aftermarket gauge but I thought that might be the better solution long term. I hear the nightmare stories of leakage. I did have one on a previous car without incident tho.

 

[Dana67Dart]

Is it a factory gauge or aftermarket?

If factory, do any of the other gauges do the same thing at the same time?

If not, with the key off, ground the sender wire at the sender. Turn the key to run and watch for needle movement. Only do this for a short time, don't let the needle peg.

Assuming you don't have a loss of oil pressure.

Run the engine and with the sender wire connected move it around a little and have some one look for needle movement. The gauges react slowly so make a move of the wire and wait for 30 or more seconds with the wire in this new position. Don't again in various other positions .

Lastly you could get a 5 watt 23 ohm resister and wire it between the sender wire and a good ground. With the key in the run position it should read about 1/2 scale. Leave it that way for the same amount of time it takes for the failure to happen.

And sealer on the threads is a wives tail.

You would have to have a 1/4" of tape finger right to be a problem (slight exaggeration)

 

[rickseeman]

I had a similar problem 2 months ago. 0 oil pressure, factory gauge. It turned out to be, and this is a weird one, the battery cable, where it grounds to the block.