25 DB Oil Pressure Gauge is Very Slow

[Guest oldodgeboys]

The oil pressure gauge on my 25 DB is very slow to respond. When I start the engine the gauge stays on zero for several minutes before s-l-o-w-l-y moving up. After that it operates fine.

I ran different viscosity oils with the same result. The oil pump output flow is fine and immediate on engine start-up.

I removed the gauge and briefly cleaned the oil path with a little gasoline. The gauge worked fairly well for about one day, then it was slow again. My guess is there is goo build-up in the gauge.

Do these gauges use diaphrams or bourdon tubes? If it is a diaphragm type, is it steel or rubber? I could clean the oil path with some MEK, but I dont want to potentially ruin the diaphragm.

[Guest John1918]

What about the non-return valve in the oil line just above the water pump? Unscrew the bung and there should be a spring holding down a ball-bearing to stop the oil draining out of the oil galleries and back down the pipe to the oil pump when the engine stops. You will need a magnet or magnetized screwdriver to remove the ball to inspect it and if it's seating OK.

While everything is out fill up the pipe with an oilcan sqirting vigorously (good clean oil) then quickly replace the ball, spring ang cap before you start the engine.

John

Edited August 27, 2009 by John1918
additional info (see edit history)

[Guest oldodgeboys]

Thanks John, that's a good thought but I don't think that's the problem. I had the valve apart not too long ago and I inspected the ball and seat...they look ok.

Also, the gauge reaction speed changed significantly just after rinsing the gauge oil path with a little gasoline, so I'm fairly sure the problem is in the gauge itself.

If all else fails, I'll try to rinse the gauge oil path with a solvent such as MEK and hope for the best.

[TonyAus]

The gauge has a copper bourdon tube so any solvent is unlikely to harm it. You might also check the needle pivots are not binding and apply a little clock oil to them. Careful application of very low pressure compressed air combined with the solvent might solve your problem.

[Guest oldodgeboys]

Thanks for the info on the bourdon tube. I'll try the MEK next. Thanks again.