foundvettelifeisgood

I'm getting what sounds like a pinwheel spinning behind my oil pressure gauge and the needle vibrates a tight span. Only when fully warmed up, and increases with speed and/or rpm. I'll need to study it further and report back, but I'm looking for initial suggestions as to what it could be.

The car is an 81 coupe in very good condition, always garage kept and very clean. Is the 81 oil pressure gauge still fed with a plastic straw pipe, like my 72 had? Could it be the speedo instead? No rocking needle.

Thanks.

C3 4ME

My first thought before I read your entire description is speedo. It's easy enough to disconnect the speedo cable from the speedo and see if the sound goes away, it just clips into the back. I'd do that first and then focus on the oil pressure gauge if the speedo isn't it.

7T1vette

Your oil pressure gauge is electric and has a signal wire coming from a sending unit plumbed into the engine's oil circuit. I suspect that the sending wire is fraying somewhere (most likely under the hood and at the connection to the sending unit). That would yield an erratic signal which would tend to drive the oil gauge 'nuts'. If the 'pinwheel' sound seems to match the movements of the gauge needle, that's the problem. You just need to find the offending wire/connection and repair it. (If no problem with the sender wire, check the power and ground feed wires, too.)

Sluefoot

Actually it's EASIER to disconnect the speedo cable at the transmission by far then from under the dash!! Hear me now & believe me sooner!

AND.....if U do that, it's not that much more hassle to pull it back into the engine bay area, raise it up & lube it at that time!

7T1vette

Make sure that noise is coming from the speedo area before you go to the trouble of messing with that cable....

foundvettelifeisgood

will do. i was at Carlisle today and bought a new cable in case that's the problem i'll start with the oil pressure wiring. where is it on the engine, top rear like my 72?

7T1vette

I believe the sender is down around the oil filter. Lots of environmental 'issues' to affect wiring in that area.