Oil Pressure Gauge - pegged when ignition 'ON' and engine is off - 95 E320
 

Hi all. I've been on this board for several weeks doing tons of research before I bought my '95 E320 (75k) a week ago. My first MB (former volvo guy) - and I love it.

I'm a DIYer, totally. Just yesterday I replaced the front brake rotors/pads / valve cover gasket. Great posts on this board helped me with each task - thank you very much.

For my question - I'm a bit worried about my oil pressure, as I just discovered my oil pressure gauge peggs (number "3" on the gauge) when my ignition is on, and the car is not running. And when the car is running, the gauge still pegs. I did read somewhere that this could be a faulty oil pressure sender or wiring issue, OR....something shady could've been done to mask low oil pressure - like wire the gauge to where it pegs when the ignition is on.

Can you guys please advise me on where this oil pressure sending unit is? And what steps I can take to figure this out? I appreciate it so much.

Best regards,

71Rcode
Dallas, Texas

Ok - found the oil pressure sending unit. It's on the oil filter cannister - and I could access it from under the LH side of the car - directly under the filter cannister.

There's a single black wire that comes out of the sender - the unmolested wire then feeds directly into the firewall (along with another wire bundle).

What would cause the gauge to peg? Clogged unit? Clogged 'passage' to the unit? Maybe I just need to pop another sending unit in place. I'd appreciate any advice. Thanks guys!!

Pretty sure a new sending unit will fix you right up.
You could try, with the key on, taking the wire off, and see where the needle goes. ;)

Sender is bad. It could be the sender lead has grounded to the chassis/body though. Do as Manny suggests and unplug the wire see what the gauge does (should zero unless the wire is bad). Sender can be checked with an ohm meter, good sender will show open when the engine is off a bad sender will show continuity. New senders run about $65 or so.

Mike and Manny - thanks - will do. I'll check the continuity and probably order a new sender. Thanks much for your reply.