Burning oil

[blkwdow]

Hey i bought a 1990 tsi, about two weeks ago.. Took it for a little test drive and as soon as boost hit, blue smoke came out of the exhaust.. I took off the intake side of the turbo and it had some shaft play, i got another turbo with no shaft play and it is still smoking.. The car now smokes at idle a little and than more once you hit the gas pedal.. I was only able to research a little due to me only having internet on my iphone at the moment ( just moved ) My guess is its the rings or the valve seals.. The motor has 204 thousand miles on it so iam guessing that it is going to be the rings.. I found a short block on craigslist and the guy is stating that it has 1g rods and 2g pistons and 30k on the rebuild, he is selling it for 425.. the reason he is selling it is because he dropped a valve and had it replaced.. I was wondering how i can check to make sure that this motor is legit before buying it??? or should i just spend the money on new pistons and rings?? or should i just get the head looked at first??

I did a compression check and its all above service level and within the 10 or 15psi of each other.. Found oil on plugs when removed if that helps determine the problem..

Forgot to mention, the motor starts up with no problem, just smokes... No knocking or pinging

 

[misphit]

Could also have been a blown seal in the turbo you took off which was dumping oil into the exhaust. After replacing the turbo with a new one, it will take a bit of time to blow all of the oil out of the exhaust. So, give it a few days.

 

[DeadsEvolution1]

After my turbo was leaking I had to wait like 100 miles before all the oil came out of the exhaust. I ended up taking off the intercooler and cleaning it. Cleaning the O2 housing and the upper intercooler piping

 

[blkwdow]

I will go and pull the intercooler and check for oil and clean that out.. But im still leaning towards the rings and valve seals.. I havent connected the downpipe back up yet, its just coming from the o2 housing at the moment.. Thank you for the advice

 

[DeadsEvolution1]

Have you done a compression test? If you really want to find out if it's your rings do 1 of 2 things. Do a compression test dry so just normally. Record the numbers for each cylinder. Next add a cap of oil in each cylinder and do another compression test see if the numbers go up. If they do it's your rings.

Or do a leak down test. Uses a compressor to test it and can tell you exactly how much pressure is blowing by the rings

 

[blkwdow]

I went and did a wet and dry compression test...

DRY: 135, 140,135,135

Wet: 150,150,150,153

 

[DeadsEvolution1]

Up 15psi with oil, I'd say rings

 

[68442]

I've seen worse compression and no smoke. I just went through this. Turbo was terrible, changed it and still smoked bad. My case it was coming out at idle and fogged when driving. Did several other things but in the end changed my valve seals with the head on. Smoke went away in about 5 mins of idle time after it all left the exhaust.

 

[blkwdow]

I think that i will give the seals a shot first... Since it will be done either way... Thanks for the good info...

 

[68442]

The Eurosport spring compressor and a air supply made short work of the seals. Bad part is timing belt comes off and the cams have to come out. Just takes time......Good luck!

 

[blkwdow]

Finally got around to changing the seals and it wouldn't start right up. I undid the cas and turned it slightly and it started right up. Still is smoking but nowhere near as much. My question now is, is my timing off since I had to turn the cas to get it to fire?? Had no spark till I turned it, idled fine than it started to rise as the car was warming up.

 

[And_44]

Yea, possibly. The CAS is sensitive. A 1-2mm turn on mine changes my timing about 5 degree's. And bad timing will effect your idle causing high idle, low idle, even surging/hunting.

If you consider yourself a decent grease monkey you could also change out your own piston rings if the assembly (Crank, rods, pistons) is in good condition. Can do all that with the block in car by removing the oil pan and head. Bit more time consuming then valve seals more detailed. If your crank is damaged or needs replacing though I believe the front case needs to be removed and you'd have to pull the engine then, replacing the rods/pistons can be done though with block in car and oil pan/head removed.

 

[blkwdow]

Thanks I'll tear it back down and see if it still lines up correctly. If not than it's back to square one.