Has anybody primed an oil pump on a 6 cylinder 3.0L diesel? I just dropped it in the car and it runs great but no oil pump. It was working fine before and did not know I needed to prime it.

 

Normally, you prime the pump before you put it in with engine oil or light grease. I am not absolutely certain about this procedure, but I have read on other threads that you can open up the oil filter canister, remove the filter, and fill up the canister with oil. The oil will drain back into the sump, but in the process should prime the oil pump. I would soak the oil filter in oil, replace it in the canister, and button her up. I would not run the engine for any length of time unless you know that the oil pressure is up. Good luck!!

 

That's what I am trying and still nothing. Not sure if there was any other tricks. Someone told me to use low pressure air to force the oil through the lines and into the pump. But it seems like that would just force more air into the system.

 

I used to use that technique when I rebuilt VW Beatle engines, only I had access to the oil pump pickup tube before I would put on the bottom plate. I would use clear plastic tubing, and slide it over the pickup tube. I would then fill the tube with oil, and use air pressure to push the oil into the oil pump. With the Mercedes engine, I would not know where to start regrading the oil circulation pattern. I will try to look around some more and see what I can come up with.

 

Unfortunately I didn't realize/think of this when I had the engine out. Now it is in. In order to get this 3.0L to fit in a 140 body style I had to swap oil pick up tubes and oil pans. I had a great opportunity to prime it.
I think if I just fill it with enough oil, it should prime right? Then after it has run at idle and I know I have pressure, I can shut it down and drain some of the oil.

 

hmmmm, if you swapped the pickup tubes I think I would go back and remove the pan and tube and compare the new tube with the old and make sure you did the installation correctly. If the engine worked before you put it in and this is the only thing you changed, this is most likely where the problem lies.

 

I have the old engine sitting in front of me and the oil pick up tube. There are just four screws and no gasket. All I did was unbolt them and swap them over. But you are right. If everything else fails, go back to where you started and that would be it. What ever happens, I will let you know.
Thanks for all the input.

 

yeah, I'm certainly not trying to be accusatory or to disparage anything you did. but I do know that whenever I have a project go south, if I go back to the last thing I touched, I'm usually right on the mark. It's tough being blonde.

 

At least you have an excuse 'cycleboy'......I'm not blonde. Just the thought of lifting this thing up to get the pan off really depresses me. I've been working on this project a few hours a day for 3 months. I finally got it all in and running great......minus the oil pressure.

 

I certainly wish you the best. I think my wife would die of a heart attack if I ever finished a project.