can anybody help me
 

FOR MY 1990 300 SEL BENZ ANYBODY CA HELP ME WHAT IS THE PROBLEM OF THE OIL PRESSURE THAT IF IT'S HOT THE ENGINE THE PRESSURE OF THE OIL GO DOWN TO 0 READING OF THE OIL PRESSURE GAUGE AND YOU WILL HEAR THE NOISE FROM THE TOP OF THE ENGINE. I TRIED TO REV AGAIN SO THAT THE PRESSURE OF THE OIL COMES UP BUT IT'S NOT, SO WHAT I AM DOINY IS I WILL TURNED OFF THE ENGINE AND WAIT FOR 10 OR 25 MINUTES ANG TRIED AGAIN TO START AND THE PRESSURE WILL COMES UP AGAIN. CAN YOU HELP INSTEAD THAT I WILL ASK ANY MECHANIC HERE.

could be your gauge is defective.

any suggestion
 

Joel,am pretty sure that the gauge was not the problem because i tried to do the mechanical way. I installed the mechanical gauge(oil pressure gauge) and the reading was the same. If the engine was cold the reading was 60 psi and let the engine idle fro maybe 30 minutes and the oil pressure reading will go down to 2 to 0 and that is the time you can hear the small knock on the valves but not so loud. I tried to change my oil with the SAE 10W30 but it is still the same.But anyway what is the best oil that i need to use for this kind of engine? What is the weight that you can recommend? Where is the location of the oil pump? Can i repair it by myself? Or do i need to take out the oil pan? Thank and i really need your help guys and i appreciate it.
Emer:)

Emer,

It's difficult to say what's wrong with your car but my guess is that a different brand or viscosity of oil will not help. I suspect there is a bad pressure relief valve or loose bearing or something like that causing you to lose oil pressure. Are you sure you're hearing a valve and not rod knock?

My advice is to start a new thread and title it more specifically like "M103 oil pressure problem." Maybe that will catch the attention of those on this list intimately familiar with your engine. To take nothing away from the excellent advice you've received thus far, of course.

My M103 oil pressure can be as low as .3-.5 bar when idling in drive. I sure hope it's not developing the same problem.

Good luck.

Sixto
91 300SE
81 300SD