NEED your experience/advice mk4gti1.8t

[nowjustonly]

****** update 03/14/2014- turns out a pcv valve filled with frozen gunk was causing oil to back up in the turbo, and out the seals. Temporary fix by venting the crankcase via the dipstick, and thawing out the gunk.- thanks for your help everyone! hope this helps someone else.********************************************* **************************************


I am going nuts.this is only my third car, second vw, first turbo. Thanks in advance for reading this.

I bought a modded 2000 gti 1.8t ( awd with an aeb head) from a dude back in july. It ran beautifully all summer and fall. As far as i know it has been chipped ( revo stg 2), de-cat, EVAP/SAI/N249 delete. There is also other stuff that was in the Kijiji ad that i don't remember.

Then in November i blew the turbo. Just driving to work one cold morning when suddenly my rear view mirror filled with white smoke. By the time i got to work i had gone through nearly all of my oil.

long story short i bought a used ko3s from a guy. i installed it, and to celebrate drove the car from (basically) chestemere to bragg creek and back. car will not boost past 5psi. The next day i take it to vw, they say mechanical failure on the n75, i say ok. started the car the next morning to get to work and maybe 5 mins down the road that turbo blew. white smoke, oil pressure light, yaddda yadda.

long story short, i rebuild the ko3s using a kit from gpop shop. i install it. i buy an n75 and install it. both on monday. the car commutes beautifully for Tuesday and Wednesday. no boost issues. i add CERATEC on wednesday. thursday morning i go to start the car and once the exhaust heats up, white smoke, oil pressure light. I've blown the turbo. yadda yadda.

so here is my question. why is this happening?

i have one theory. i noticed that the PCV valve is routed through a "T" that ends in the crankcase breather valve and the valve cover. i imagine this means that blow by from the cylinders is being routed straight into the intake track, post MAF but pre- turbo compressor. this could mean particles of oil and whatever all else is being deposited into the turbo, and then consequentially, throughout the entire intake system. if water vapor freezes in the turbo, or soot accumulates, it could cause premature failure of the seals. A Catch can would solve this. right? am i missing something simple that would cause repeated turbo failures like this?

I am not excited at the prospect of having to uninstall and re install the turbo for what is now the third time, but I've resigned myself to it. (first world problem) i want to avoid doing it again. i want to find out why my turbos keep blowing, fix that, and be done with this issue. i have done other ancillary things in the trouble shooting process, and as part of the rebuild( replacing lines, cleaning intake hoses, passages, ect). Please help me as i have less then a year's experience with the 1.8t.

[MechEngg]

Re: NEED your experience/advice mk4gti1.8t

Do you prime the turbo with oil before starting it? Seems like your turbo isn't getting oil, either the feed or drain lines might be clogged. Sometimes can happen from using non synthetic oils

[nowjustonly]

Re: NEED your experience/advice mk4gti1.8t

Do you prime the turbo with oil before starting it? Seems like your turbo isn't getting oil, either the feed or drain lines might be clogged. Sometimes can happen from using non synthetic oils

a fair suggestion. but yes i did prime it and no, i checked and cleaned the oil feed line/ banjo's for coking and blockages before the latest install. i also replaced the oil return line. And i only run synthetic.

this quote from vortex maybe sounds interesting though what are your thoughts on the pcv system?: "A clogged PCV valve or restricted breather system will generate excess pressure in the oil lubrication system, pushing oil through the weakest spots of the system which are seals. With excess pressure in the lubrication system, oil could leak to the compressor side of the turbo and then the turbo will push it to the intercooler, throttle body, intake manifold, combustion chamber and then piston will push it out to the exhaust. by removing the oil dipstick, excess pressure in the crankcase will be released to the atmosphere instead instead of being built up in the system pushing oil past the weakest point. or, too much "blow by" which is caused by bad rings can also increase your crank case pressure, and not allow oil to flow down the drain hose from the turbo. this backs up the oil and makes it ooze out along the shaft and into the exhaust/boost pipes.

a blocked pcv system, or one that is improper, and for example routes boost into the crankcase or is blocked, can cause the same thing."

thanks for your quick reply.

[Kane]

Re: NEED your experience/advice mk4gti1.8t

When you say blown turbo is the turbo shaft broken? Is the turbo siezed? Or is it pushing way to much oil through the seals?

When i hear blown i think broken turbo shaft and some carnage.

[Ponto]

Re: NEED your experience/advice mk4gti1.8t

What oil have you been using? And fuel? Or guess more so what did the PO use (just saw you said you use synthetic)

I know people who have blown stock turbos at less than 100k km because of conventional oil and regular fuel.

Also what are you driving like? Are you allowing time for the turbo to cool before shutting the car off? What about start up? Allowing it to warm up properly befoe going into boost?

[BaggedGLI]

Re: NEED your experience/advice mk4gti1.8t

If your oil pressure light comes on, maybe start by checking your oil pressure?

[Ponto]

Re: NEED your experience/advice mk4gti1.8t

If your oil pressure light comes on, maybe start by checking your oil pressure?

Actually ya duh. I am retarded.

My buddy was having oil pressure issues. His oil pick up line was plugged by a oil bottle seal.

[MechEngg]

Re: NEED your experience/advice mk4gti1.8t

In my opinion a blocked PCV system will not really result in a blown turbo in such a short period of time. You will start experiencing a tons of blow by and smoke out the exhaust before you will completely blow a turbo seal.

[witchcraftz]

Re: NEED your experience/advice mk4gti1.8t

Oil not getting to the turbo and causing them to blow? Read about an oil filter that came apart and gunked up the interior of the oil feed lines.

[nowjustonly]

Re: NEED your experience/advice mk4gti1.8t

When you say blown turbo is the turbo shaft broken? Is the turbo siezed? Or is it pushing way to much oil through the seals?

When i hear blown i think broken turbo shaft and some carnage.

I found my problem. it was a clogged pcv valve. thanks for asking that question. i may be using language that isn't specific enough because i just don't know enough. when i say blown turbo what i mean is, oil is leaking past the seals into the exhaust as evidenced by thick white exhaust smoke (among other things) with a distinctive odor. When the first turbo "blew" i didn't even bother to check shaft play because a rebuild was too daunting. I just looked for a replacement ko3, and found one. when i experienced the same symptoms again i decided not to chance it and bought the rebuild kit. Oddly, the old bearing, washers, seals, clips and other parts looked great, with the exception of some mild discoloration. and light coking. Now that i know what the problem was, this makes sense. oil can get past the exhaust if there is enough pressure, without the seals or oil deflector suffering mechanical failure. my turbos didn't fail completely.

[nowjustonly]

Re: NEED your experience/advice mk4gti1.8t

What oil have you been using? And fuel? Or guess more so what did the PO use (just saw you said you use synthetic)

I know people who have blown stock turbos at less than 100k km because of conventional oil and regular fuel.

Also what are you driving like? Are you allowing time for the turbo to cool before shutting the car off? What about start up? Allowing it to warm up properly befoe going into boost?

I found the problem. It was a clogged pcv valve. I run 91 octane, and while i don't know exactly what the previous owner ran, he was the one who cautioned me to only use synthetic. When i took the valve cover off to replace the gasket there were only trace amounts of sludge. certainly nothing to indicate conventional ( as far as i know). As far as my driving habits go, it's been hit and miss since July. I'm not a spirited driver at all really, and after the first turbo "blew" my forum browsing lead me to start warming up and cooling down the car. I also looked into a turbo timer, but did not in the end decide to go with it. Someone told me that because the turbo is relatively small, and water cooled, the temp is theoretically limited to the coolant, and it was an unnecessary mod. The flash point of my oil is 236c/456f, well above the 190 shown on the dail in dash. how hot does a turbo get?

[nowjustonly]

Re: NEED your experience/advice mk4gti1.8t

If your oil pressure light comes on, maybe start by checking your oil pressure?

I feel you. this is going to sound silly, but how does one check oil pressure? aside from watching the level on the dipstick change, or witnessing a puddle form under a running car?

[nowjustonly]

Re: NEED your experience/advice mk4gti1.8t

In my opinion a blocked PCV system will not really result in a blown turbo in such a short period of time. You will start experiencing a tons of blow by and smoke out the exhaust before you will completely blow a turbo seal.

you were right. i drove the car today after clearing a blocked pcv and lost no oil, saw no smoke.

[nowjustonly]

Re: NEED your experience/advice mk4gti1.8t

Oil not getting to the turbo and causing them to blow? Read about an oil filter that came apart and gunked up the interior of the oil feed lines.

hmm. can a filter be switched without draining the sump? i have a fram in there now, but want to put a mann back in.

[BaggedGLI]

Re: NEED your experience/advice mk4gti1.8t

You'll lose some oil, but need to top it up after, wont be a full change.