Testing oil pump

[nautidawg1968]

I'm trying to figure out if my oil pump is working correctly. I pulled the outlet line off and no oil coming out when engine idling. However, when I loosen the bleed screw on the oil pump, plenty of oil comes out. Why would I be getting oil from the bleed screw but not get oil into the outlet line?

 

[nautidawg1968]

Re: Testing oil pump

P.S. on above post ... it's a 1998 Merc 150 2.0L carb.

 

[irishflies]

Re: Testing oil pump

Check your last post. You will find info there.

 

[nautidawg1968]

Re: Testing oil pump

Yes, thanks Irishflies, for your earlier response, however, it did not completely answer my question. When I removed the oil driven gear, I did not see the telltale plastic shavings, nor did the threads of the shaft look worn, and nor was the coupling bushing cracked. This observation combined with the fact that oil does bleed out of the bleed screw makes me hesistant to conclude the entire oil pump is faulty. Yet, I still get no oil flow through the oil line.

 

[irishflies]

Re: Testing oil pump

I am sssumeing that you are running the engine when you are bleeding the pump. As per the trouble shooter in the manual. If you run the engine as I said with the outlet hose disconnected and you see know oil then it is a internal problem with the drive gear. There is also a motion sensor right next to the pump.Also there is one on the engine reservoir cap. Buy the manual and do the trouble shooting. Also, The alarm module could be faulty.here is a quick over view of the trouble shooter.If you run the engine and the alarm soundsthere are 4 possible causes. These only apply if the oil reservior in the engine if full.A faulty engine ignition system(incorrect voltage pulse being sent to the warning module. Defective low oil sensor in the fill cap of the reservoir. Defective motion sensor at the oil injection pump.The drive system of the oil injection pump.If you say that when you run the engine with the link rod disconnected and you disconnect the outlet hose and no oil is flowing then your drive system is faulty. To my knowledge this can only be the cause.I just found some ifo to your last question.As per the manual,with engine not running loosen the bleed screw 3 to 4 turns.Maybe you were not running the engine when you were checking for flow from the outlet hose. Good luck and again do yourself a favor and buy the manual.there are filters and check valves that could be causing your problem.The trouble shooter will fix your problems.

 

[irishflies]

Re: Testing oil pump

One more thought to the ansewer of your question. Bleeding of the pump should be done without the engine running. That means you are seeing only the oil that is being bled. Bleeding the pump only fills the pump. Since you don't see oil from the outlet hose with the engine running your drive system is faulty. With or without the engine running you will see oil when bleeding the pump if there is oil in the reservoir. It is gravity fed. The whole system is pressurized by the engine.Try ruuning the engine and loosen the fill cap one half turn. If oil comes out of the cap your problem is is on the engine side of reservior.