low oil prerssure
 

95 s500 oil pressure drops below 1 bar when AC is on and a little above 1 bar when idleing with Ac off. Goes up to 3 bars when driving. Also get a ticking noise at idle. Other than the oil tubes blowing out can they also get clogged? What should I check for?

REPLACE ALL THE OIL TUBES FIRST. IF THERE AREN'T ANY BAD ONES, I WOULD LOOK AT THE OIL PRESSURE RELIEF VALVE.

trintrick,

I am pretty sure your oil pressure gage readings are normal for a fully warmed up car. I know the German manual for the W123 Diesels says 0.3 bar at idle with the car fully warmed up is ok, provided the meter pegs when the engine is under load. All my cars, except my 190E 2.3-16 go below 2 bar when idling fully warmed up. The 190E 2.3-16 always stays pegged at 3 with the engine running. But that is the only car I have seen that never drops off the peg when warmed up. Sounds like your idle lowers slightly when your A/C unit comes on.

Good luck, Jim

Thanks for the information!

on the other hand - how long has it been since an oil and filter change. I have noticed that over a period of time the oil pressure will drop slightly based on how long it has been in there.

I agree; your readings are perfectly normal -- check your owner's manual.

On the other hand, I got tired of looking at readings of 0.5 bar at idle, in drive, in summer. Since I switched to Mobil 1 15W-50, never gets below 1 bar.

Had the same problem, checked with MB shop they said levels were normal. Changed oil and put in Redline and the levels are higher now. Does not go below 1 bar.

Also it might not be a bad idea to check that little used obscure book in the compartment where you probably don't keep your gloves to be sure you are using oil of the correct viscosity for the season and climate.

Peter