Oil out of dipstick - Chevy and GMC Duramax Diesel Forum
01-04.5 LB7 Duramax Powertrain Discussion of components that are directly involved in the power production and all that is needed to get and keep the truck moving . Engine , Transmission, Etc.

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post #1 of 7 (permalink) Old 11-16-2019, 10:52 AM Thread Starter
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Oil out of dipstick

Bought truck earlier this year its a 2001 gmc 2500hd LB7. Few weeks after buying it started blowing heavy white smoke from the pcv vent. I put seafoam in the fuel filter and double dosed my fuel with howes and it went away.

A couple of months later i was hit with mystery limp had a new pump put in didnt solve the problem, continued to have hard starts while warm. Changed the oil and had 20L of oil so i assume an injector is leaking.

Today, a month after changing the oil i have noticed oil leaking back out of the pcv vent tube and when i removed the dipstick oil splashed rapidly out of the tube. This never happened last time i had the pcv vent problem.

Any suggestions? It is very cold outside, could this lead to a problem?

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post #2 of 7 (permalink) Old 11-16-2019, 11:20 AM
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Have you confirmed there are no restrictions in your crankcase vent. system? After doing that, I would run a compression check to rule out excess "blow-by" from possible failed rings, piston issues. etc.

2013 3500 long bed crew cab. Purchased at approx. 80,000; now have 91,000, convert to CP3. DPF "triggerd" a limp mode, so was cut out of the vehicle & cleaned by a DPF cleaning co., on re-installation, everything back to normal. Would never ever think of something as nasty and as anti bunny wabbet as a full-delete...after all..dosnt everyone like the fun & excitement of being stuck by the side of a Interstate in the ran while towing when one's truck's computer decides to go into "limp mode"...?.
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post #3 of 7 (permalink) Old 11-16-2019, 02:50 PM
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Could it be your injector(s) are so bad that your crank case is filled to the teats with fuel? Or the return lines?

I would assume that a 50/50 mix of fuel and oil in your crank case has wreaked havoc on the internals unfortunately. Oil analysis stat!

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post #4 of 7 (permalink) Old 11-16-2019, 11:28 PM
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Drip some oil off the dipstick onto a paper towel. It will form a halo if it has fuel in it. If it has major blow by out the dip stick or oil fill tube next step is a compression check.
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post #5 of 7 (permalink) Old 11-17-2019, 03:21 PM
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Have you checked the PCV system? There should be a servicable PCV valve next to the alternator but I'm not real familiar with the gen 1 Duramaxes. IIRC there are PCV check valves on the valve covers also. If previous owner did a PCV reroute, there could be a clogged/pinched, ice block tube or plugged catch can. Worth taking a look....

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post #6 of 7 (permalink) Old 11-18-2019, 08:02 PM
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I would say injectors, dont know what else would cause it to make oil unless the fuel return line is leaking.

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post #7 of 7 (permalink) Old 11-18-2019, 10:54 PM
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pretty good video on an injector return leak.

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