AAZ Runaway

[Wessty]

I hope this is in the right section.

I've been working on a 95 Golf TD 250,000 km. This car had set in a field for the last three years, wheels off and practically on the ground.  I've resealed the engine, changed the timing belt and idler, and replaced every brake line and hose on the car as well as the rear brake components.  

During the last month of working on it, it had been started and run many times, and always starts right away with a fully charged battery.  I had it on several short road trips to test the work I've done and its run well.  

Today I took it to have a set of tires installed.  It's about a 15 min ride to the garage.  It made this trip without incident.  On the way back from the garage, approximately 5 minutes from home I was climbing a slight grade about 80km/hr when the car lurched and then took off like it was possessed.  I  turned off the key, with no result, so I put the car in fifth gear applied the brakes and stalled it out.  I got out of the car and there was thick black smoke for at least 100 yds behind me.  

I got help and had the car towed home.  I then disconnected the hose that connects the intake to the valve cover, thinking that maybe this is where the oil was coming from.  I started the car and the engine tried to runaway again, and I stalled it out.

I'm thinking that the only other source of oil could be from the pressure feed on the turbo itself.  If that's the case would I be correct in assuming that the seals have let loose and oil is getting into the compressor side of the turbo?

[Vincent Waldon]

Yuppers... a "runaway even with the key off" is usually oil... turbo seals or a ton of blowby.  If you pull your turbo hose (between turbo and intake manifold) you'll know fer sure... 98% odds-on turbo seals.  

It's not uncommon for it to "pop" when under load... like when passing or going up a hill.

[Wessty]

Wow, less than five minutes for a reply, thanks.  I'll take the turbo to intake hose off in the morning to inspect it.

[Wessty]

I just came in from inspecting the turbo, not good, it grenaded itself.  The compressor wheel is jambed up against the housing and theres  oil everywhere.  There are shards of aluminum in the hose from the turbo to the intake manifold.   

It sounds like I'll have to remove the head and check for damage from shrapnel off the compressor wheel.

I guess I didn't get it shut down quick enough.

[Vincent Waldon]

I guess I didn't get it shut down quick enough.

Actually I don't think there was anything you could have done differently...the engine would have run away *after* the compressor went sideways.   The main thing was that you kept your head and didn't head into the ditch... or oncoming traffic.

The other thing you may want to look as you put things back together is your compression... the reason being that it only takes a couple cc's of liquid oil in any given cylinder to bend a rod.  After my last runaway I had a rod that looked like this:





(the scoring on the piston is the result of a horrific injector (TDI engine), not related to the runaway.  The broken skirt is the result of the crank counterweights meeting the skirt due to the connecting rod's new shorter length. )

After the runaway this engine started poorly when cool but ran ok and had a reasonable amount of power... when I ran the compression I got 450/300/100/310.... three bent rods.

Just something to check... you may well have avoided this particular nuance of a grenaded turbo.

[Quantum TD]

Gruesome

[Wessty]

Here are some pictures of the piston tops, some of the compressor vane material did make it through the intake.

Later tonight I'll go out and take some more of the head and turbo.

#1


#2


#3


#4

[Wessty]

Some pictures of the head and turbo.

#1


#2


#3


#4


Turbo

[Wessty]

Well, I've got everything all cleaned up, I'm going to button it back up shortly.  New head gasket and head bolts, intake exhaust gaskets. 
   I lucked out and was able to find another turbo, a K14 this time.  It turns freely and there is very little axial and radial play.  From reading here I was able to take the waste gate actuator off and free it it up, as it was stuck in the closed position. 

pb blaster is your friend

Both mating surfaces were in really good shape, but thanks to the info from good people here, I was able to lap it with valve grinding compound.Once the valve was freed up I was able to move it with 20lb air pressure.

Once again thanks to everyone here, I've gotten some great info here to proceed with this repair.

[R.O.R-2.0]

Well, I've got everything all cleaned up, I'm going to button it back up shortly.  New head gasket and head bolts, intake exhaust gaskets. 
   I lucked out and was able to find another turbo, a K14 this time.  It turns freely and there is very little axial and radial play.  From reading here I was able to take the waste gate actuator off and free it it up, as it was stuck in the closed position. 

pb blaster is your friend

Both mating surfaces were in really good shape, but thanks to the info from good people here, I was able to lap it with valve grinding compound.Once the valve was freed up I was able to move it with 20lb air pressure.

Once again thanks to everyone here, I've gotten some great info here to proceed with this repair.

it should move with about 6-8 psi pressure. 20 psi out of a K14 is pretty much beyond its efficiency rating..

[Wessty]

Well, I've got everything all cleaned up, I'm going to button it back up shortly.  New head gasket and head bolts, intake exhaust gaskets. 
   I lucked out and was able to find another turbo, a K14 this time.  It turns freely and there is very little axial and radial play.  From reading here I was able to take the waste gate actuator off and free it it up, as it was stuck in the closed position. 

pb blaster is your friend

Both mating surfaces were in really good shape, but thanks to the info from good people here, I was able to lap it with valve grinding compound.Once the valve was freed up I was able to move it with 20lb air pressure.

Once again thanks to everyone here, I've gotten some great info here to proceed with this repair.

it should move with about 6-8 psi pressure. 20 psi out of a K14 is pretty much beyond its efficiency rating..

Thanks for that info, I'll put a boost gauge on the car when get it running, to make sure its not over boosting.

[burn_your_money]

I hope you have already noticed that you will need a different exhaust manifold, downpipe and oil return line.

[Wessty]

The turbo I bought came on the exhaust manifold and had the return oil line attached.  Again thanks to everyone here, I found out the differences searching and reading this site.

[burn_your_money]

That is good. You can drill out and cut your original downpipe to make it work with the new turbo.

[Wessty]

The engine is all buttoned up and running fine.  I replaced the oil with an inexpensive brand and ran it for a few miles, then dumped it and put some quality oil and new filter in it.  There's a very slight bit of lag with the K14 as opposed to the K03, but the owner says it feels fine.

It went for a 3 hr run on the 401 with out a glitch.  The owner, a close friend said it runs smooth (for a diesel) and pulled well on the hills, he's quite happy with it. 


Once again thanks to all who made suggestions, this forum is a great resource for those  interested in all things VW diesel.