TheSamba.com :: View topic - Oil pressure light / buzzer false positive?

Fri Apr 11, 2014 2:55 pm

Oil pressure light / buzzer has been quiet for a couple years now. It used to come on during really hot days when engine temp would rise and oil would thin out. I added Lucas Stabilizer and that helped. Also kept oil level midway between dipstick marks, and that seemed to help. I replaced the low side oil pressure sensor a couple years ago. But yesterday, taking a short drive in 72 degree weather it came on and stayed on...no matter the RPM. Pulled over, shut off motor, checked for massive oil loss...all good. Level on dip stick...full (probably too full, but it's been full since last oil change and no buzzer) Drove off...engine purring like a kitten...Oil pressure light / buzzer comes back on. I drove 4 miles home and parked.
Only after letting the van cool down a couple hours, I went for a short drive, pressure light / buzzer stayed off.
Could this be engine temp related? I might have a bad temp gauge sender, since my temp gauge barely moves no matter how long I drive. Just put in a new thermostat and TEMP II sender. Coolant temp warning LED tests good.
Where should I start?

Fri Apr 11, 2014 4:45 pm

If your oil pressure light came on then its one of three things. Bad oil pressure switch, fault in wiring/circuit or you actually have low oil pressure. Check wiring/circuit first, then switch then think about the engine third.

Fri Apr 11, 2014 10:06 pm

Check your hot oil pressure.

http://volksweb.relitech.com/21rodbrg.htm

Sat Apr 12, 2014 10:03 am

the wire (brown) that goes over the backside of the engine case on the drivers side can/does chaffe thru and will make shorts to the case metal.
this wire can be erratic as the engine moves/vibrates.

I usually add a plastic wrap to protect/insulate this from the case.

Sun Aug 17, 2014 5:37 am

This ^^^ finally happened to me this week...

At first the OP light would flash <just very briefly> once in a great while, always on a bumpy road.
Oil level always checked out good, and I NEVER saw the light at low idle, so I was pretty sure I needn't panic... :roll:

Slowly it progressed to flickering <mostly off> and then <mostly on> and it was time to investigate...

The double connector for the (brown) OP switch wires had hung down to contact the exhaust stud at
the DS front; as it bounced around it had slowly melted, allowing better and better contact over time.

Fixed with a gentle cleaning, 3 good layers of electrical tape and a juidciously-placed zip tie.

All good in the 'hood... 8)

Thanks, Samba!

- Dave