turbo oil blow - by on intake?? HELP

[JFerg65]

I know I've seen a similar question posted but cannot find it. I've have a new to me 96 K2500 Sub with 138,800 on it. I'm pretty certain this is the original turbo. I've had it approximately six weeks and have put 2000 on it. Runs like a dream, I changed oil within first 100 miles of getting it. I've had to add approx a 1/2 - 1 quart since the oil change. Am noticing some oil residiue / blow by at the coupler from the turbo to the intake. I think it's increasing.

I'm assuming.... yes assuming this is not par for the course. How much trouble am I in? Is this on it's way out and should I just plan on having a new turbo on the shelf? Or, do I wait until I'm burning up 2-3 quarts betwween oil changes before proceeding? I don't want to be making metal confetti out of the turbo vanes!!!

No smoke, great power and consistant mileage. I am getting a an intermittant service engine soon light, comes on during sustained idel at lower rpm will reset it self after a couple of days. Is this realted. Am planning on getting the code once it's thrown again.

If the consensus is have a new turbo handy, any rec's

Only other mods at this point; K&N airfilter in stock box, and remote mount pmd on driver side fender.


Thanks

[DennisG01]

A small pool of oil there is normal. Play around with the turbo vane shaft. There should be very, very little axial play. While pushing the shaft one way or another (and rotating the shaft at the same time) you should not be able to ge the vanes to scrape the walls.

[JFerg65]

I've been poking around the net, and saw a post elsewhere, that attributes same symptoms to a bad CDR valve. I'm going to take a look in the a.m.

Here's my next question; Can the cdr be pulled off and blasted with some carb cleaner like you do with a pcv valve and reinstall... or are you better off just replacing? I read at ssdiesel it should be replaced every 30k.

Any suggestions??

[Hubert]

No the CDR does not need to be changed every 30K. Cleaned probably/maybe. Replace when it won't pass the cdr test and cleaning doesn't help. .....Go to Heath diesel dot com and read his blog on the CDR. Its been covered here a handful of times. Don't use carb cleaner or harsh solvent. Clean with hot soapy water (off the truck) dry and put back on if its gummed up.

Clean K&N filter and make sure fender (air intake) is not obstructed with leaves birdnest etc etc. Are you running any kind of prefilter sock over the K&N? Make sure its free breathing. Try a "paper" filter for 3K miles and compare before replacing CDR. You might be surprised paper works pretty good.

1-1.5 qt of oil per oil change (2.5-3K miles) isn't bad. Good practice to check oil often and keep topped up. I try and check every 2-3 fill ups or before or after long runs on highway or towing (anytime extended elevated boost).

Get codes checked probably unrelated but might be something else looming.

[gmctd]

Yep - remember - that oil has been accumulating for 139kmi, since the day the truck rolled off the assembly line - clean it all up and check again, next month

And do the CDR\blowby check on Bill's website.

[JFerg65]

Thanks for the feedback, I'll do all of the above today.... the new siding on my house can wait to pick up again on Sunday!!

My K&N is just a direct replacement for the stock box, so no prefilter / sock. You know though I ran a tank of fuel through before I changed over and did not notice anything in regard to an increase in the oil blow by. Could the increased airflow be affecting the "draw" out of the crancase, or is that what the CDR is supposed to do, limit it?

I'll track down the CDR check clean everything, top off the oil, and then monitor. If it continues, I'll throw a paper filter back in and do the same. It sure would be nice if ends up being an easy fix.

Thanks again for the assistance. The members certainly help with the old learning curve!!!!!

[gmctd]

The CDR limits crankcase vacuum to less than 6"H2O - 'bout a baby's breath - the system is calibrated for normal filter use and deterioration - the dirtier the air filter, the greater the vacuum.

So, no - the less restriction, the less available vacuum.

[JFerg65]

Well.. I sit here drinking my celebratory beer, yes it's before noon, but this deserves one in my opinion!

Thanks to all for the information this morning because it made this job smooth sailing at my end.

I completed the water test on the CDR and it is OK, so I pulled the rubber housing from the airbox to the turbo and there was no pool of oil, just a fine film if that is what you want to call it. Minimal

At that point I wiped stuff down and pulled the CDR and cleaned her out with some kerosene, and now she is all back together.

Needless to say, hopefully, my friend got me all freaked out for nothing. I think the oil / discoloration on the rubber hose from the turbo to the air intake that goes to the top of the motor was simply 138,880 miles of crud with a little bit of oil / vapor that has escaped past over time. I snugged up the bolts at each end and hopefully that is that.

NOW... the only thing I noticed when I was at the turbo end was the slightest bit of play in the vane shaft. It didn't bind or grind or kiss the sides when turned. AM I OK with that small amount of play????

I also found out that I will need to update my mods list on my truck. I finally got around to checking out the water pump and housing. What do you know, I have the HO water pump and dual thermostat set up!!!!

MY HAT GOES OFF TO THE SEDGEWICK COUNTY FLEET MANAGEMENT IN SEDGEWICK COUNTY, KANSAS!!!! They know how to maintain vehicles!!!
Thanks again for all the assistance today. Hopefully somebody will confirm my hopes that I don't need to worry about the small amount of play in the vane shaft for now.

NEXT on the list after my bypass oil filter, will be the Kennedy fan clutch with duramax fan upgrade!!

[DennisG01]

[quote=JFerg65]
NOW... the only thing I noticed when I was at the turbo end was the slightest bit of play in the vane shaft. It didn't bind or grind or kiss the sides when turned. AM I OK with that small amount of play????
quote]

Totally acceptable. Sounds like you got a good one!

[rameye]

good for you!!

I was reading my service manual update and GM had a reccomendation to use RTV silicone on the rubber sleeve leaving the turbo attaching the intake for a tight seal.

I was getting alot of blow by on the outside of the rubber sleeve and this eliminated it.

[JFerg65]

Thanks
I read about the importance of doing this. It does appear the last person to have the hose off did use the rtv to the reassembly process. I may take that hose off if the problem increases.