m103 (190e 2.6) 0 oil pressure on gauge

[bleucamaro]

I drove the car 2 days ago, and oil pressure was fine (1.5+ bar at idle, 2.5 low rpm cruise, and pegged 3 bar under load & higher rpm).

I started it today and the needle didn't move off the peg, 0.

It sounds normal. I backed it out of the garage to wash it, and put it away later. I checked the oil level, full. I removed the oil fill cap, the cams were wet and the bottom of the cap was too.

I will pull the filter tomorrow and see if it is clogged. It's relatively new. The oil is clean and clear.

I suspect it is 1 of 4 things:
- Electrical between the sensor and gauge
- Bad Sensor
- Oil Blockage at the sensor
- Bad Oil Pump/ chain / mechanical

I have a couple questions:
Is the oil side of the sensor accessible from the oil filter fitting with the oil filter removed (to see if its blocked)?

If there is a bad wire or sensor, will the gauge default to 0 bar, or 3 bar?
(The sensor has the 2 wire snap type connector on the back, and the wiring diagram shows 3 wires at the gauge; pwr, gnd, signal). Will absence of the signal pin at 3 bar while absence of power stay at zero?

If it is something more serious, like the oil pump, are there any tell tales to look for before pulling the oil pan off?

Thanks in advance.

[optimusprime]

Oil switch are known problems just pick one up and change it over .

[97 SL320]

There is a oil filter bypass for a restricted filter so don't bother taking the filter out.

Measure sensor resistance with the engine off and running, if no change the sender is bad.

[Diseasel300]

As mentioned above, the oil pressure sender is electric and is a known failure item. Take the oil filler off with the engine running and look for oil slopping around in there. If oil is moving around in the rocker cover, you have oil pressure and know to look at the sender unit.

[Hit Man X]

I have replaced them twice on the 300SEL in my 15ish years of ownership on that car. They crap out often on daily driven cars in my experience.

[Sugar Bear]

All good advice above. 103 motors rarely
have oil pressure problems but often just need a new sender. Much easier to change with the oil filter removed.

Good luck!!!

[bleucamaro]

You guys are fantastic. Thanks!

I'll check resistance on the sender, and verify oil movement at the filler when I get home from work.

Any difference in quality/durability between the $20 URO, $60 VDO, and $80 MBZ sender?

[Diseasel300]

Originally Posted by bleucamaro

Any difference in quality/durability between the $20 URO, $60 VDO, and $80 MBZ sender?

Friends don't let friends buy Üro.

[Mxfrank]

my new out of the box VDO began leaking promptly after installation.

Photos from inside an oil pressure sender

[Rrrockhound]

Originally Posted by bleucamaro

You guys are fantastic. Thanks!

I'll check resistance on the sender, and verify oil movement at the filler when I get home from work.

Any difference in quality/durability between the $20 URO, $60 VDO, and $80 MBZ sender?

The Meyle sensor is $28 and has been working great for me for 3 years.

[Hit Man X]

Originally Posted by Mxfrank

my new out of the box VDO began leaking promptly after installation.

Photos from inside an oil pressure sender

I think there was a bad batch of VDOs for a while come to think of it, I seem to recall the one on the 300SEL was a VDO I replaced.