Hello all, My mercedes scared the #*$& out of me today,,,, I was idleing with the AC on,,, and i noticed the oil pressure was down below the 1, almost near the zero,,, i gave her some gas and the guage shot back up,,, then when it would idle,, it would go back down to the one,, jitter around a bit and go around the 0..... all the time the engine would run fine,, it not make any unusual noises or anything like that...


I took it to a local mercedes mechanic and his conclusion is that it is the guage sending unit,,,,,, but he didnt really do any diagnostic work,, he just kinda looked at the car and said it was the sending unit. :S for gods sake I hope he is right cause that part is only 80 bucks..

has anyone experienced this before?? funny oil pressure guage movement??

thanks a lot,,,, and any info is greatly appreciated..


Mike[/align]

 

Only real way to know what's going on is to measure the oil pressure using another gauge at the point where the electrical sender fits.

Quite possible that it is the electrical sender unit BUT other possibilities exist like a stuck relief valve, worn pump, bearing problems BUT MB's are pretty reliable in this area.

Mileage?
Last oil change?
Correct spec oil?
Correct spec filter?
etc.

is this a new problem or is it the first time you have looked at the gauge when hot / idling.

Stuart

 

Its hard to say because i only bought the car a few months ago,,,, this is the first time im noticing it.....

the car has 180 KM,, so about 115 000Miles. im useing the amsoil 5w40 european formulation,,,, and i also use the MB oil filter......

im fairly confident its just the guage,, cause some times it seems to flutter around abit.. i have an appointment to replace the sensor next week :S man i just hope thats the problem,,, I would assume anything further is gonna cost me some serious cash,,,,,

 

I had this same problem. It was a loose connection at the electrical sending unit. I replaced the wire connector and all was OK.

I miss the old days when the oil pressure gauge was really a pessure fed gauge.

Sam