I'm a newbie first off so I'd like to say from what I've seen I love the forum.
My problem is I Just picked up a '98 12 valve automatic with 146k miles, while idling it puts out a blue haze..kind of worries me. I'm no diesel mechanic but ive taken a look at it and noticed the oil return from turbo to waste gate is blocked off on both ends with bolts shoved in the hose...not sure what that is about but trying to narrow down suspicions, i didn't figure it eas rings with the miles it has. So I figured I'd ask people who knew what they were talking about...could this cause my blue haze? Thanks for your time.

 

blue smoke is "typically" oil burning sometimes it looks blue but is actually white which is "typically" low timing and un burnt fuel timing

 

What I'm saying though if my return line is capped off is it sending excess oil through it? It's not horrible but at a drive thru or anything you can see a descent amount of blue.

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Update: my bad I was looking at the wastegate hose, what an idiot haha. Just not sure why my 140k mile motor would blue smoke at idle like it does.

 

ya if ur oil inlet was capped off ur turbo would be tattered quick. wats ur timing set at? whens the last time u changed ur fuel filter

 

Have no idea what my timing is set at, I just got it Thursday. It seems like it would have to be excess fuel because it only does it at idle not while moving, if I lay into it and let off it takes it a while to come back, I just slid the plate forward to see if that changed anything and it smokes alot more blue after its idling now. But if I lay in it and let out and let it set for about a minute and it starts doing it wouldn't that make sense that it's overfueling? Kind of like having too big of carb on a car, you lay in it and it's needing that fuel so it's fine, but you let it idle and it loads up? I have no idea if it has different injectors or not. I don't know how to check timing on a diesel? I can a car all day long. Is it much different?

 

It's not abnormal if it smokes a light blue & white when it warms up. But if it smokes blue everytime your back at idle then there's an issue. I would suggest you find a reputable shop, and get them to adjust your feul pump and timming.

This morning -20, it smokes a light blueish has on start up, then it goes to white after a few mins, then everything goes away. Normal that it runs a little rich when it's dead cold, and the grid heater runs it's cycle.

I just got my fuel pump adjusted, timming advanced 16 degrees, running 90 hp sticks and she runs great now.

Corbin

 

my truck has 60,000 on the clock and does the same as 98 cummins. if it is doing it all the time when it is up to temp there is a probple with blow by at the rings or a bearing out of the turbo because some IDIOT plugged the wastegate off!

 

I would say that Turbo 2332 is right, it might be the Turbo, if the wastegate was blocked off, that aint good for the turbo at all. I would say that the turbo is leaking possibly. Pull the piping off and see if there's oil in there, clean it off and drive it for a day or 2 and check it again. If it's covered in oil, chances are the turbo needs new seals, if there is a kit out there, or it's time for an upgrade.

My truck has 552880 kms on it, stock internals, and runs like a charm.

I had this issue happen to me when I was racing Subaru's, the main seal in the turbo had started to leak, and luckly we pulled the turbo, before she blew, saving expensive motor work.

Corbin

 

But if it were rings why wouldn't it do it going down the road or better yet all of the time? It's just after it idles for a little bit, none at all anytime except for idle.

 

compustion pressure is higher so if they are just starting to get tired this may be the symptom you are experiencing. look at the turbo first. is there a bunch of blow by coming out of your slobber tube?