Mk4 ALH suspected turbo bearing failure - need info

Was driving up a steep climb to a low pass and experienced severe reduction of power, smoke out exhaust, and a squeal followed by a rattle that sounded like a bearing failure. The car will drive a short distance while smoking with the noise intermittent. I installed a tow hitch and towed the car home for repairs. Here is the car's background:

May 2001 VW Golf 1.9L TDI 5sp manual ALH 148,000 miles with VNT15 turbo

Other than timing belt replacement, no major till recent when a valve lifter wore through. Replaced were the valve lifters, #1 intake valve (need to check for proper install height), camshaft, oil pump, oil filter, and engine oil.

Car operated just fine and I started making trips back and forth over a low highway pass. At roughly 300 miles after major, the car objected profusely during the final stretch of reaching the 1,000' summit. {I know Californians, this is a bump compared to your 11,000' high passes.} This would be the time the turbo would be in full load as the pass is very steep {think its 7% grade).

My car starts fine, it smokes bluish, lacks power but still mobile in terms of yards, and gets noisy as it warms up with an intermittent squeal and also rattle sounding like a turbo bearing failure. I popped open the valve cover finding no problem, compression testing is 595/590/595/595, and climbing underneath tracking the noise led me to the rear of the engine around the turbo. A sound probe indicates the noise is mainly emitting from the compressed air side. Taking off the turbo oil return line resulted in only a dribbling of oil coming out while the engine was running when I expected a steady solid stream.

This forum has write ups on removing the turbo either from atop or two ways from below. However, there is little regarding troubleshooting and options. I figure the N75 and MAF are not an issue since they would lead to the squealing/rattling noises. I did find a 100K used turbo with all auxillaries and oil supply line attached and including shipping available for $400. A brand new bare bones turbo is $800 then add shipping. Here are my questions I hope some of you can timely answer (June 2012):

July 2012 update with turbo problem found -
Replies confirmed suspicion the turbo had failed also saying the causes are rarely known.
Replies identified the VNT15 is a journal type versus the ball bearing type so not repairable.
Replies mentioned that lack of sufficient lubrication or foreign debrie is the common failure cause.
Replies mentioned once back in operation there would be lots of smoke as oil in intercooler burned out.

Removed the old turbo finding its shaft broken and the compressor side blades a bit mangled. I obtained the 100K mile used turbo and installed it. Part of the install was to replace the hard oil feed line with a flexible one, remove the troublesome and somewhat useless EGR apparatus, and test turbo oil supply line flow. AHA!!! The flow was a dribble; insufficient for adequate lubrication. Problem: In the short 300 miles after top end work noted above, the 5 quart engine oil had lost 3 quarts without any warning. Being I have been using a high quality synthetic (AmsOil) and B100 (high lubricity), the rest of the engine seems to not have been harmed. After adding 3 quarts, the turbo oil flow was as would be expected. No leak can be found onto the ground can be found. It going somewhere!!!

During teardown, a cup of oil was removed from the bottom of the intercooler and it was mentioned the car would smoke billowing for a while. True, it sure did, and it took 20 miles on the highway during a downpour for me to clean out 90% of the intercooler contamination without donating to the local Christmas fund.

Your symptoms sound a lot like when my turbo died. Be careful running it, the blueish smoke may be unburnt fuel, but also could be oil if the turbo is dumping oil in the intake. You need to take the turbo intake pipe off from the airbox to turbo and feel inside and see if the turbo shaft spins smoothly or if there is play. You can also pull the lower intercooler pipe and see if oil is filling up your intercooler - another sign that the turbo is bad and dumping oil into the intake. It will only be a little oil at first, but when the turbo goes completely, oil will fill up that intercooler and feed into the engine, potentially causing a runaway.

When I pulled my turbo, the impeller had broken in half, intake side could spin completely independently of the exhaust side. It had been making a bad bearing sound for a couple days, then one day a loud rattle started as the impeller was completely shot at that point and oil was being dumped into the intake.

Given the earlier history and problems you found, your diagnosis of a dying/dead turbocharger is spot on.

A good used unit would work; and careful attention must be paid to getting oiling problem solved with the caveats mentioned by crzyjt in mind.

A new unit will work well. The oiling is critical regardless of which unit you choose.

blue smoke is a sign of burning oil i thought

Deleted as moot posting - see start of latest update - turbo replaced cause discovered.

There is no bearing in the turbo. It is a shaft riding on a thin film of oil. You most likely can only replace the whole turbo.

My guess.........some crap made it to the Turbine side of the Turbo.

The VNT 15 only has one large bushing (bearing) with the Turbine and Impeller (compressor) on each end of the shaft. The oil filter should have "caught" any debris from replacing the oil pump. My guess is the oiling from the oil filter housing is just fine. It it is smoking that means oil is there. If the Turbine got hit with some crap coming out of the head that could cause an "imbalance" situation resulting in compression ring seal failure on one or both ends of the shaft (no rubber seal). Also, if there was an impact of debris to the Turbine, most likely the "tips" of the blades were damaged or shaved off and now it's function is tremendously limited.

Is there much axial play in the shaft? There should be a small amout.

Deleted as now moot - latest update at initial post - replaced turbo with cause determined.

400k is steep for a turbo with 100k.

I guess if you have no other options, maybe. But a new/rebuilt one is going to be "only" $1200 or so. (I bought a slightly used one from another list member, and it worked out well).

The change-out job is not "free" either. You need to replace intake and exhaust gaskets, change your oil, filter, and I would strongly urge you to do a very thorough cleaning of your intake system.

It's really important to make sure that the oil supply line is clean, and works.

When my turbo went, the intake vanes were mangled, and it looked like someone recycled a few cans into the intake. There's no way I know of that anything could have gotten dropped in there. It's a sealed-system, right? But something got loose. Piece of crud? I dropped a nut during earlier work? who knows? I know that I was having "issues" for months (oil consumption, noises, a surreptitious run-on) before I decided to replace it. (I replaced it before it failed outright - but it sure looked completely borked when I pulled it out). I rarely read a turbo thread where the actual failure is identified - and that's usually by the person who has the experience and tools to rebuild it. Your best bet is to replace the whole thing, and make sure that the replacement unit, and the systems upon which it relies (clean oil, clean air intake, vacc-actuation), are in good shape.

Available turbo

I've got a used VNT 15 that's only got 40k miles on it, as well as a new oil line and gasket kit that I'd let go for $500 if you're interested.

I believe ID parts has new VNT 15's for 700.

Do not start the engine until you have replaced the turbo AND removed all of the oil from inside the intercooler! It will smoke like a freight train as it burns the remaining oil out of the exhaust.