the electronic controls sense a problem and will not let it get above idle...upon close inspection the bearings are worn?..yet it has only 100 hrs on it...I check for lack of oil flow to the turbo charger and its OK so is the return...it senses low intake manifold pressures and limits the rpm.... stumped?...I change it and it fixes it...but only for a little while, I'm on #3...cheap rebuild?
Is impeller hitting/rubbing the housing?? Most are not worn out if not hitting and have virtually no end play. Are you starting it up with dry bearings? Should prelube or crank engine without starting till lube makes it to turbo. Oil return plugged or oil feed line pinched? Restriction in exhaust (like colapsed muffler) or inlet plugged (towel in filter) somehow?
Hauling it with the exhaust exposed to the air stream causing the turbo to spin without oil?
its not hauled enough to matter on the open exhaust....impeller not worn enough to wear on housing but it bleeds oil into the intake causing blue smoke when running of course it all clears up when turbo is changed out...exhaust pressures too high? maybe pushing oil out of bearing into intake??..has anybody experienced this issue on this high tech engine.
This is in the diagnostic section of the Service Manual for the 6068T engine that you have: Check for Turbocharger Oil Seal Leak RG9440 –UN–23JUL98 Turbocharger Oil Seal Leak Test A—Crossover Tube B—Oil Return Line Seals are used on both sides of the turbocharger rotor assembly. The seals are used to prevent exhaust gasses and air from entering the turbocharger housing. Oil leakage past the seals is uncommon but can occur. A restricted or damaged turbocharger oil return line can cause the housing to pressurize, causing oil to leak by the seals. Additionally, intake or exhaust restrictions can cause a vacuum between the compressor and turbocharger housing, causing oil to leak by the seals. 1. Remove exhaust pipe (shown removed) and crossover tube (A). 2. Inspect the turbine casing and crossover tube for evidence of oil leakage. If oil leakage is present, perform the following: · Inspect turbocharger oil return line (B) for kinks or damage. Replace if necessary. · Check the air intake filter, hoses, and crossover tube for restrictions. · Check the exhaust system for restrictions to include position of exhaust outlet. 3. Perform necessary repairs and repeat test. CTM104 I agree that you must pre-lube the bearings in the turbo before reinstallation.
How many hours on engine? Whens the last time the crankcase breather was cleaned?
4000 hrs and crankase breather was cleaned right after first turbo failed.
99% of the time, and don't take this the wrong way... It's either a restriction, dirty oil, low oil pressure or operator error, as in, not letting the engine idle for a few minutes to let the turbines wind down before shutting off the machine, or reving the engine on start-up before the oil pressure has reached the turbo inlet. Remember, when you shut off the engine you loose oil pressure..and if the turbo is spun-up, she's running dry.. There's a product on the market, and I forget the name of it, that looks like a glass bowl that goes between the turbo oil inlet and the line and holds oil and drips into the inlet of the turbo when the engine has been shut-down.. Just a thought, might be something to look into. Have you contacted your rebuilder to find out why they are failing..?? 99% of the time you can tell by looking at the bushings, turbine shaft and rings..lack of oil, ran hot or excessive engine blow-by..
Check for a engine air intake leak after the turbocharger. Pay close attention to hump hoses and charge air cooler. Few years ago had a low houred 770C that was using oil and blue smoke out of exhaust. Replaced turbo and by end of day blue smoke reappeared. Found one of the silicone hump hoses was leaking at connection. Repaired and problem and problem went away. I talked to Deere's DTAC boys several days later and they explained that without backpressure provided by boost pressure oil was able to be pushed from turbo center housing to compressor side of turbo. We had same problem with one of our service trucks after driver hit a deer. Went through 2 turbo's, oil on intake side, until he found that collision with deer had cracked the air to air aftercooler.