Just bgot word from Shop .. it seems there is only 2 PSI drop in 2500 RPM when Hot , Cold. I also Took It to a Mercedes dealer ( only good shop arround ) and the gave me some confidence in driving the car back home There argument was that Light comes off and never comes back on after 1000 RPM and that engine sounds are OK .. their quick Diagnosis is that I have overfilled Oil compartment and That The Oil I was Using was much Lighter than this Thick 20w 60 That I´m Using Now.

 

PSI . were 2 lower than normal at 2500 RPM on Hot temp. On low temp PSI are normal.. an light does not come ON..

Shop is telling me that as a cheap remedy is to increase Idle RPM to 900. since My Idle RPM are at 750 RPM ( arround ) for example when I turn the AC on the oil Light comes OFF Just by the Increase in RPM.

 

I dont know what to tell you other than done mess with the idle speed, change the oil again in 1,000 miles and see what happens.
If the oil psi numbers are fine then either it is a fluke, sludge floating around and getting sucked up into the oil pick tube from you going 15,000 miles on your last oil change or a bad oil psi sending unit.

 

Spike Thanks for the help..

I checked the sending Unit and I´ts Fine. I already changed the oil Twice and still the light only comes on at 750 RPM and Only when It´s Hot or after 30 Minute drives.. Ive been reading that Oil viscosity could cause this? but wouldnt Know what oil to Use. Mabe something thiner I´m currently Using 20w60.

I dont thing I´m to lean on Increasing Idle RPM either .. but only as a last Resource.

 

Yes the weight of the motor oil can cause this, I have seen this before with older cars and tractors, if the oil is to thin then at idle the oil psi is to low, increase engine speed and the oil psi comes back up because the oil pump is moving more oil.
20w-60 (20w-50 here in the US) would be the oil to use for where you live.
Now, with that being said, what brand of oil is it? Is it a full synthetic motor oil?
If it is not a full synthetic motor oil then try and find Mobil 1 15w-50 or Castrol Syntec 20w-50.
Pennzoil also offers a 15w-50 in full synthetic.

 

Knock knock...who's there? Rod (bearings).

Yes....put some 20w50 or 60 in it (you can get 20w60 is the US special order - we use it on the track in cars without external oil coolers or when it's really hot out).

 

I now have Quaquer State. 20w 60 Multi Grade (Not synthetic.). and added a Bottle of Quaquer High Millage additive. But Still the Light is coming on at Idle. a Little Less Do.

Only when car is Hot.

Daryl Should I be Looking at the rod Bearings ??

 

Should you be looking at rod bearings?
Maybe, with dino motor oil, high ambeint temps, driving on the expressway at speeds in excess of 85mph and going 15,000 miles between oil changes there is a very good chance that your bearings are gone/going out.
Basically oil psi is how hard the oil pump has to work to push oil through all the tiny little passages and through all the bearings, the tighter the bearings the higher the oil psi because the harder it has to pump oil.
Bearings wear out, spaces get bigger and the oil pump has to work less thus oil psi drops.
When oil gets hot it gets thin, all oils do this BUT full synthetic is less likely to thin when hot, that is why I say to use full synthetic.
Dont use any oil additives, LR does not recommend them and in my opinion they or just a waste of money.
SO, change the oil again, switching to full synthetic, like I already said Mobil 1 and Pennzoil Platinum both come in a 15W-15, Castrol Syntec comes in a 20W-50.
All three of these are full synthetic.

 

....what Spike said. If everything else has been covered and you still have low oil pressure, it's normally worn rod bearings. There really is no "looking at them" - you're pulling lots of stuff and checking them with a plastigauge and replacing them. Not a fun job, and you just might be able to keep it going for a good amount of time of you keep up with good oil changes using the heaviest stuff you can find.

Spike is again correct on the synthetics - even at the same weights, I see higher oil pressure on the same vehicles. And that even varies between brands....some seem to be heavier than others. It seems the xxw-yy on the container is just an estimation at best.

 

Thanks Spike.. will do so first thing tomorrow ..

Just drove 60 milles ( very slow ) light never came on .. when slowing down to Idle.. Im getting my hopes Up again. Since I dont think it is to serious However Ill tell shop tomorrow to check those bearings. and change the oil again when i have it.

Should I check anything else ??

P D : Found some castrol 20w 50 Full synthetic ..