Fuel in crankcase L83 Tahoe

[Stuart Sherry]

2016 Chevy Tahoe, 5.3L V8, L83 engine, ~208,000 miles and 6100 hours on the engine

 

TLDR:

Oil analysis from blackstone shows 4% fuel in oil, dipstick level increase about 0.5" over about 1200 miles. HPFP already changed.

 

Long story:

I was getting P0172 and P0175 fuel trim codes and slight increase on the dipstick between oil changes (about 7000 miles, it would increase by 1/4"). Read through some threads and found out about the high pressure fuel pump allowing fuel to leak into the crankcase and the fuel vapors getting sucked back into the engine causing the rich trim codes I was getting. Changed the HPFP and all seemed good. No codes and oil level was stable.

 

Next oil change after HPFP replacement, and level on dipstick was good. Fast forward to the next oil change after that and the dip stick level was 1/2" over full but I never got the trim codes.

 

I am assumming a leaky injector(s) but looking for some advice before I spend the money to figure out which one or change them all or maybe something else???

 

So far, I have checked compression in all cylinders and the they range from 200 to 210 psi. I boroscoped the pistons to see what I could see of the injectors and I could not conclude anything, maybe someone with more expertise can. Pictures attached. I have been tracking mileage and engine hours as well as dipstick level and it seems the first 500 miles / 20ish engine hours, the oil is pretty stable. Sometime within the next 500 miles / 20ish engine hours, the level starts to rise significantly to 3/8" to 1/2" above the full mark.

 

Final note is the spark plug from cylinder #8 has some carbon on the insulator which is different compared to the other cylinders. Some pictures attached of the plug from cyl #8 and cyl #1 for reference. Spark plugs have about 98k miles on them.

 

Any advice or suggestions to help me justify an expensive repair would be helpful. In the meantime, oil changes every month at the moment:(

 

Thanks!

[newdude]

13 hours ago, Stuart Sherry said:

2016 Chevy Tahoe, 5.3L V8, L83 engine, ~208,000 miles and 6100 hours on the engine

 

Long story:

I was getting P0172 and P0175 fuel trim codes and slight increase on the dipstick between oil changes (about 7000 miles, it would increase by 1/4"). Read through some threads and found out about the high pressure fuel pump allowing fuel to leak into the crankcase and the fuel vapors getting sucked back into the engine causing the rich trim codes I was getting. Changed the HPFP and all seemed good. No codes and oil level was stable.

 

Next oil change after HPFP replacement, and level on dipstick was good. Fast forward to the next oil change after that and the dip stick level was 1/2" over full but I never got the trim codes.

 

I am assumming a leaky injector(s) but looking for some advice before I spend the money to figure out which one or change them all or maybe something else???

 

Any advice or suggestions to help me justify an expensive repair would be helpful. In the meantime, oil changes every month at the moment:(

 

Thanks!

 

 

 

 

208,000mi, I'd have done not only the HPFP but injectors as well since you had so much fuel dilution going on.

 

Until you replace the injectors, shorten your oil change interval.