Blow by??

[Thump]

I posted not too long ago about my turbo apparently leaking oil from the back side, above the return line (where the turbo meets the downpipe).
Went to the dealer the other day and they came back saying that it was blowby from the engine, as it's not a sealed environment. "
***? I am used to a little blowby from a gasser, in the valve covers, if you have too high of oil pressure or something is clogged.

Is this even possible on this engine?
I've looked as best I can and cannot see where it would come from. I am also at a loss as to why I'd have blowby.

It wasn't a lot of oil, but any is disconcerting to me on a 30k mile engine.

Anyone got any advice? I am simply leery of this explanation.
Thanks in advance.

 

[jwilliams3]

You could in fact have a blow by issue with your engine.

Excessive blow by can cause a turbo to leak prematurely.

 

[WDimig]

could also have a slightly stopped up drain line, if the turbo cannot get all the oil out of it that is being pumped in there, well it's going to find the next least path of resistance, that is your seals in the turbo.



wes

 

[Thump]

In my experience, blow by is a result of excess pressure in the engine. Pressure in the engine is expected and normal, and there are relief measures taken in the design, but blow by is a failure of these items to either work properly or they are required to work outside of their limits. This can be caused by many things such as rings not seated, allowing compression pressure to get past them and exert itself in the crankcase. In a Diesel, since the injectors sit in the oil path, it could be due to a leaky injector or two, which would mean that I am filling my engine with fuel and reducing the lube capacity of the Rotella.

The dealership told me that it wasn't in the turo itself, but due to blow by from the crankcase. However, I cannot see evidence on the block of any oil. I recently had the intake tube off all the way to the turbo and still couldn't see anywhere that this could be coming from. In addition, once a seal leaks, especially in a pressure location (which the turbo see every time you press the pedal) it probably won't ever seal properly again because it's been stretched enough to lose its seat. :shaking head:

Not wanting to sound like a smart arse or anything. I am leery of this dealership already, but went there on the advice of a member here. Personally, I think they're trying to pull the wool over my eyes. To some extent they can, because I am very new to Diesel engines, but I'm definitely not new to engine building especially in the race and performance realm.

I guess I'll have to dig further into the engine and take in my findings so they can just fix it.
Sorry, but "it's just blow by due to this engine not being a closed system, nothing to worry about" isn't an answer that I'll take. Yes, i have blow by... what the heck is causing it is the real issue. Blow by, as a term is the rings issue, but excessive pressure, causing oil to exit the case is a problem that needs to be investigated. Since this is a 2x4, not heavily loaded often, bone stock and not hot rodded (yeah... right LOL) there should be no problems of this sort.

I talked to the previous owner about his driving habits and he told me "there was a break in instructions (foreign guy) in the manual that (he) follwed prior to loading it with the boat. " This boat was a 32' cruiser weighing about 10K with trailer. So I know that it got good workouts to help seat the rings as the manual states.

Yeah, ticked off is a good description of me and it's been nearly two weeks since I got this "diagnosis. " What a waste of my time that visit was.

<charlie brown>AARRRRGH!!!</charlie brown>

 

[betterthanstock]

Take off the oil cap at idle and feel the blowby.

 

[MMeier]

Take off the oil cap at idle and feel the blowby.

Is there a "better" test for measuring blow by on one of these trucks?

 

[Prairie Dog]

Every eng has some blow by, it's totaly normal. You can do a search on this forumn and find lots of discusion about it.

 

[nickleinonen]

Is there a "better" test for measuring blow by on one of these trucks?

use a manometer or magnehelic gauge to measure actual crankcase pressure [+ or -] in inches of water. . i am not sure what the limits on these engines are though [the engine i work on run in a negitive [ - ] crankcase pressure: up to -6"h20, the engines shutdown past +2"h20]

 

[Thump]

enough blow by that it creates evidence of a dri[ coming off the turbo is more than factory specs in my mind. If you've exhausted the abilities of the factory measures enough to blow to a device that sits away from the engine (note that there was no evidence of oil on the engine) and then drip from there is excessive and should be investigated further, no?

 

[Prairie Dog]

So oil is coming out of your turbo someplace?

 

[Vaughn MacKenzie]

The dealership told me that it wasn't in the turo itself, but due to blow by from the crankcase. However, I cannot see evidence on the block of any oil. I recently had the intake tube off all the way to the turbo and still couldn't see anywhere that this could be coming from. In addition, once a seal leaks, especially in a pressure location (which the turbo see every time you press the pedal) it probably won't ever seal properly again because it's been stretched enough to lose its seat

You dealer is wrong- the turbo is most likely causing the blowby, not leaking because of it.



You hit the nail on the head when you said the turbo is under pressure much of the time. If the seal is bad, where do you think this pressure bleeds off to? It goes right into your engine via the turbo oil drain tube, causing a significant rise in crankcase pressure and increased blowby. I think you have a simple case of a defective turbo. . . I think your turbo alone is the root of the problem, not your engine.



Vaughn