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Oil leak oil pressure issues

5K views 11 replies 2 participants last post by  012duramax4x4 
#1 ·
I just picked up a 2005 duramax for a steal. The owner said the rear main seal is out, but when parked on a hill the oil drains out the back. Oil is coming out of a "seap hole" on the bottom of the bell housing. When I cranked it up checking for blowby I nonticed the oil pressure gauge wasn't moving so I killed it. I cranked it again and it came up a little but acted like it was sticking. Are these gauges bad about going out? How can I check to see if it has oil pressure. I'm scared to crank it again.
 
#3 ·
On a LLY engine, about the only way you can get that much fuel in the oil is from the front injector pump [CP3] seal. An injector can leak some but usually not in that quantity.

On the early LB7, there are fuel lines under the valvecover and they,-- and the injectors can leak and dump a lot of fuel into the crankcase.

The 04 and 05 did have dash gauge stepper motor problems, but on your truck, your oil was so thin, that the pump could not build pressure.
 
#5 ·
Has no one else had this problem with the lly? I've searched for hours to find other threads with no luck. I also can't find a new seal for the cp3??
 
#6 ·
I guess you could disconnect the lines at the CP3, and see if it holds about 10 lbs of pressure. Dont go any more pressure than 10.

Sent from my SAMSUNG-SM-G920A using Tapatalk
 
#8 ·
Just changed the oil because according to the oil change sticker it was 10,000 miles over. When I cranked it, it built up oil pressure then the gauge went back to 0. I'm not sure if it's the gauge or oil pump! Truck has very little power also, and took a little while to crank at first.
 
#10 ·
I finally got my obd2 wifi reader today. I pulled the 13 mil codes two of which were p0303 and p0305 I am also reading a balance rate of 15mm on these two injectors. What does this mean?? Injector is clogged or flowing to easy??
 
#11 ·
Update: I have swapped #3 injector with #7 injector and the problem stayed on cylinder #3. I'm thinking it is a wiring/ electrical issue. I have done the ice pick trick. How do I go about testing to see why I'm getting a +15 balance rate on #3, and #5
 
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