M104 no oil pressure or oil flow
 

Hello! I just rebuild my engine. Its a m104.990 that is in a w124 now.

Just got the new rods and head gasket inn, and when i started cranking it to get oil to the turbo nothing happend, and the oil pressure sensor shows nothing eighter. Did pull out the filter to se down there while cranking, but no oil comming..
everything worked fine before i pulled out the engine.
And im sure i got everything right back together.
Anything else than a bad oil pump that it could cause this?
Got another oil pump, but hope that it would be somthkng else so i dont have to pull out the engine again for that.

Would be really thankfull for any answer!:)

did you prime pump with grease?Pack it with grease,turn engine over slowly till oil comes to turbo and rockers.

Nooo, i just filled the engine up with oil and cranked it without fuel or spark.

normal thing,is to take axle grease, and pack it in the pump,it draws the oil up for the first time.It dissloves when oil heats up.Don't use the red stuff.

now if you don't want to remove pan,and stuff,you can over fill it,byyy a gal. and a half.To get oil level to pump gears.Then crank till pressure.Then drain to right level,and start up engine.I have done this.

Really dont want to remove the pan again so i will try that! And a Gal and a half is about 5L or am i wrong?

Yeah,you could even use old motor oil,if you have too,cause you will change again in 200 miles,after rebuild.

Okey! I'm going to try this tomorrow! Thanks alot!:-)

yes I did this once with a ford ranger v6. My son did not change oil for 90'000 miles.The screen got clogged,and there was no oil pressure.We filled the engine with half diesel,and half gasoline.Bounced the truck up and down,and sideways,four time,with 2 gals. gas mix,to clear screen.Then 2 gallons motor oil to prime pump,then drained oil to right amount.It worked,drove it 30,000 miles.

If you can find a suitable fitting for the turbo oil tap or the oil sender tap, fit up a garden sprayer. Fill it with a quart or two of oil, and pressurize the system with the sprayer pump. Did you apply an assembly lube to the camshaft? It's a good idea to dip it in something like STP before you install.

Tried out both things now, and nothing...

Remove the spark plugs so you are not fighting compression ( disconnect the crank sensor to disable fuel / spark )

Remove the oil pressure sensor, install a tube and a can if possible so you don't have a mess.

Crank the engine, see if you get oil pressure .

If not, leave the oil cap on, pull the air intake cross over tube ( the one that goes across the valve cover ) plug one of the breather ports in the valve cover, insert an air hose in the other and apply 2 or 3 PSI while cranking the engine. Don't add more pressure, you might push out a crankshaft seal if you do. There might be a breather hose in the intake manifold area that would need blocked also but I haven't looked at one recently.

It will take 2 or 3 minutes.

2-3 min of cranking?

yes,and watch guage,make sure coils are not connected.my car,I can pull coil fuse to pervent starting