I NEED your ideas/ help please. mk4gti1.8t

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I NEED your ideas/ help please. mk4gti1.8t

Postby veedubclub » March 11th, 2014, 3:09 am

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 j-dubn (cool dude). 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 passages, ect). Please help me as i have less then a year's experience with the 1.8t.
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Re: I NEED your ideas/ help please. mk4gti1.8t

Postby DeleriousZ » March 11th, 2014, 4:03 pm

Did you check the oil feed to the turbo? Are you letting the car warm up completely before boosting?
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Re: I NEED your ideas/ help please. mk4gti1.8t

Postby veedubclub » March 11th, 2014, 11:30 pm

thanks! yup i did check that. turns out the problem was too much pressure in the crankcase, causing oil to back up into the turbo and out the seals, caused by a pcv valve that was frozen solid with gunk. solved. awesome.
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