oil dilution with diesel

[wrench buster]

(10-31-2025 )Rawze Wrote:  

(10-31-2025 )wrench buster Wrote:  Hi Tree, I have done the EGR tune up, cleaned the intake sensor, The rail leak down test passed. I also pressure checked the CAC, I saw no EX. leakage. From what I've read the frequent regens could be causing the oil dilution since fuel is injected in the cylinders to accomplish re-gens. Let me know what you have found out to make this happen in your cases. Thanks for your quick response.

Frequent failed regens can cause fuel dillusion to show up, in a lab report for an oil sample, yes .. but it is NOT likely going to be so bad that it measurably raises the oil levels at the dipstick.

What does the regen history look like in Insite?.

How old are the DPF/DOC uints?.

Have you actually REPALCED the IMAP and other sensors with new OEM?.. because simply cleaning them is NOT good enough!.. especially for the IMAP sensor. Have you actually takem the intake and EGR systems all apart and cleaned all the soot buildup out?.

Have you replaced the crank case filter with a new one?... or removed it all together?.

Overhead valve adjustment?.

checked/cleaned the circuit passage for, and replaced, the exhaust back-pressure sensor?. .. replaced the IMAP sensor, and Delta-p sensor + cleaned out the mounting block for it?.

etc.etc.etc.

Did anyone use any liquids for cleaning the DOC/DPF?.. if so, they are ruined and will not regen properly!.

Has anyone checked the DECOMP TUBE and SCR injeector for leakage and exhaust pipe blocking?.
info: https://rawze.com/forums/showthread.php?...07#pid1807

and yes .. DPF/SCR issues are most likely a separate thing from the oil illusion issues if it is so bad that it cause the oil dip-stick levels to raise.

Also, has anyone taken the DPF/DOC, etc. off of it and taken photos of theior faces?.. and determined what is deposited onto them?. Posting pics of the faces of the units onto the forum here can often reveal what is wrong.


- How fast does the oil levels raise after a fresh oil change?.
- Are you sure oil level rise is fuel in the oil?... or can it be from coolant intrusion?. - Has anyone sent an oil sample to a lab? or drained the first bit from the oil pan into a freezer-baggie and let it sit to see if there is water getting in?.

Thanks for your reply Tree, I have removed the air intake and cleaned out carbon, and cleaned EGR diff ports and replaced the sensor with new OEM, the back press sensor was changed when I did the DOC and DPF service, however I just cleaned the IMAP sensor and did not replace it.
I will pursue that and also the decomposition tube inspection. I estimate I had 1/2 gallon of diesel in my oil pan when I changed the oil and filter. The oil pan holds 5 gallons. I replaced the transfer pump below the HP Inj pump and When I dis-assembled the old pump the shaft looked really worn where the seals ride. Maybe that is where the diesel is coming in. This truck is doing a regen about every 6 hrs according to my INSITE.
Thanks for your input