Oil Level Gauge Pegged at High, What's Wrong?

[84porsche]

Just noticed on my way home today that my oil level gauge is pegged at high, it goes from low to high on ignition and stays high while the car is driving. I didn't overfill the oil and usually keep at mid-level. Did something fail? What do I need to do to fix this, if anything? Please help.

[john walker's workshop]

wire off the sender or sender has an open circuit (bad sender). look behind the RR tire at the sender on the outside of the tank.

[84porsche]

Thank you. I assume this is the sender. I went and looked at it and it looks normal, nothing looks out of place, loose wire. The housing looks cracked a little but could be the 22 years.

[84porsche]

How can I fix? Is this the only cause? The pressure gauge is working fine.

[qcwang]

Your sender may be broken. This happened to me about two yrs ago. The level went all the up to high as soon as you turned the ignition key.
I ended up replacing the sender after ordering from our host and everything back to normal.
I noticed the new sender made a slight scraping metal contact sound when I moved the plunger /lever back and forth and the old one was loose and made no sound when moving the lever. Not sure if it could be salvaged so just replaced it and problem solved.
I think I replaced it with my next oil change and I can't remember if I read anywhere that oil will leak out if the sender is removed before the tank is drained. Hope this helps!!

[qcwang]

If you have to replace it, it is not that hard. I ended up raising the rear of the car (I think I left the wheel on at first, but then removed the right rear to give me more room). I removed the 5 nuts and the wire and removed the sender. It has this lever/plunger/floater thing on it so you have to twist it and rotate to get it out and the new one in. The new part comes with a cork gasket which I put on after scraping off the old one and the put on the new sender and replaced the nuts and wire. I did not use any sealant with the gasket.

Oh I did drain the tank first just in case and completed my oil change after everything was back on.

[98GTW]

I've got the oppposite problem in my 77: gauge stuck at the bottom. I assume it's the disconnected wire harness near/under the oil filter, but I've looked everywhere the connector will reach and there's nothing to plug it into. I've lived with it and tracked the oil level using the dipstick, as the gauge was a little squirrely to begin with, but I'd be curious to know where the stupid wire belongs.

[DW SD]

Originally posted by 84porsche
How can I fix? Is this the only cause? The pressure gauge is working fine.

The pressure gauge is not at all related.

Typically when a gauge pegs it is because the wire from the sender either has 12V steady or direct continuity to ground. The gauge measures resistance at the sender and displays calibrated values. As has been said already, I suspect your in-tank sender crapped out. Mine did some time back. I had to change the sender.

Be very careful not to get anything in the tank. Oil from the tank directly feeds the pressure circuit in your engine. Debris would (could) directly enter the lubrication circuit in your engine.

Doug

[fintstone]

The sender is a variable resistor that changes resistance base on a float attached to an arm that rotates the variable resistor (like turning a knob). Pegged (high) usually means you have an open (broken wire or bad connection) between the gauge and the sender....or the sender is open or a bad ground on the other (ground) lead (brown) You can test for this....If you disconnect and ground the lead that goes from the tank to the gauge, you should read zero. Open (disconnected should cause the gauge to peg. That tells you if the wiring is good to the gauge. No movement would usually mean a short to ground or a short across the sender.

[450knotOffice]

Interesting stuff. I'm always interested in the exact process of a given component or system.

[RFR]

thanks! I have the same problem

[fintstone]

Since it depends on the ground (brown wire) to be anything less than pegged...cleaning up the connections sometimes will do the trick...note the greasy connections in the photo (after all...it is an oil tank).

[Joe Bob]

Tape it up and ignore the worthless piece of crap.....check your oil on the dipstick.

[84porsche]

I will try a cleaning tomorrow when I get home from work and if that doesn't work, I will try and get replaced in the next week. Thanks all, good information to know. I am in debt to you guys again.

[84porsche]

Well it is mysteriously fixed as of 5 minutes ago when I took her out for a spin.

[acapella8]

Mine does the same thing -- once pegged high - then the next run -- it works fine. I've been told (and now do) only trust the dipstick.

[Yellowbird RS]

thanks for the info!
I'm working on the same issue right now.