OK I had an interesting discovery tonight. The parts I ordered arrive tomorrow and I decided to do some prep work tonight. I wanted to get far enough that I could hose down the nuts on the exhaust manifold with pblaster to let the penetrant soak in overnight. So I took out the coolant overflow tank, the bright red samco CAC hose to the inter-cooler, the air filter box and the heat shield. When I got to the airfilter -> turbo inlet hose, it got interesting. It was very oily down there. I never did the EHM so I suspected there may be a crack in the airfilter hose. In fact, the bottom half of that hose, the part that attaches to the turbo, totally disintegrated on extraction. OK I was tugging on it a bit because its a tight spot but it totally fell apart. I think the turbo overheated enough to damage/partially melt the bottom part where it attaches. For some weeks I have heard a bit of a sucking sound that would turn on and off with what sounded like boast level so I thought it was a small leak on the boast side that would only manifest when the boast exceeded a certain level. Is it possible to have such an intermittent leak on the input side? I mean, a leak that only activates when the turbo sucks on it above a certain pressure. I gues that must be true.
Anyway it is just the last week that it started to loose power, blow smoke and make more ominous rattling sounds. That's when I assumed the turbo was gone and ordered the parts. But now I look in there and I can see a little blob of melted rubber stuck on one of the vanes. Also, there is a melted smear on the insde wall at one part where the melted blob must have stuck the vane at one time. So I am starting to hope that maybe it is not a smoked turbo after all and I won't have to go through the turbo replacement, just some careful cleaning and a new intake hose.
But not so fast. Now that I can get my hands on it, I notice exactly the opposite play as I have read that would indicate its ok. In the radial dimension there is no play at all. In the axial dimension, there is a few tens of thousandths, almost imperceptible. By radial I mean, I grab the central shaft nut between index and thumb and try to bend the shaft side to side. By axial I mean, push it in and out along the shaft. Isn't this the opposite of what I should see if it is not damaged?
Anyway, its worth a try to just clean it in place, put the new airfilter hose and all the rest of the parts back and see if it sounds better. What sorts of solvents are ok to use for cleaning? Carb cleaner seems potentially explosive for a diesel system. I suspect I will just use tweezers to scrape the little blob off mechanically and hope for the best.
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