Possible burning oil

[StigZXTT]

Hey guys,

Just wanted to put in a quick question, how often (about how many miles) do you guys need to add engine oil if you have needed to on your TT Z32's? Seems on mine I'm having to add 1.0-1.5 quarts every 1,200 miles or so. Is the VG30DETT known to burn oil? My car has a swapped JDM TT engine with rebuilt stock turbos that I got from concept Z.

One thing worth noting with my car is if I start it from a cold start and let it just sit idling, as it gets up to operating temp it'll let out some blue-greyish smoke only from the left (driver) side exhaust (could maybe be slightly bad turbo oil seal on driver side?). Weird thing is if the smoke does occur it'll go away after a few minutes of driving, and if I actually drive it almost immediately after startup it won't smoke at all.

Thanks for your input!

[mrmoose]

sounds like worn cyl or stem seals. if it were turbos it would smoke all the time, worse when you step on it and oil pressure goes up. tts dont burn oil when in boost cause the boost pressure keeps the oil from blowing by, if its idling the engine vac would draw in oil on a worn cyl or rings if i recall correctly. try using a heavier oil and see if that helps

[Shoey2]

valve guides in the head are sucking oil in under vaccum at idle...heard of it happening a few times but not that common. whats the maintenance history like? regular oil changes?

[StigZXTT]

Yeah that's unfortunately what my mechanic thought it would be. That's a bit annoying. Yes the car receives regular oil changes every 3,000 miles, the car has a TT swap completed in January 2012, all sorts of oil seals were replaced and even had to install BDE intake sprockets. The car's model year is a '90 and engine was determined to be a '92. Nothing internal besides valve cover gaskets were replaced. How difficult is it to replace valve guides? And what are the odds of the problem being the valve guides versus piston rings? I'm assuming valve guides would be the more easily repaired job.

[StigZXTT]

And the TT engine has approximately 53,XXX miles on it btw.

[Towncivilian]

Check if your PCV valve and any associated hoses are clogged, or just replace the PCV valve with a new OEM one.

[t.mcginley.jr]

My bet is on valve stem seals like mrmoose said. You said nothing internal was replaced, and the valve stem seals are down inside the heads. You would have to remove the valve covers, camshafts, lifters and then valve springs to get to them. My engine had 98k miles on it and I just replaced the valve stem seals and the original ones were pretty worn.

If it happens to be the valve guides (which I doubt) then you'll need to take the heads to a machine shop.

To rule out pistons rings, do a compression test. If you have low compression then the rings/cylinders could be worn which would burn oil.

[StigZXTT]

Ok so looking at a fair amount of engine dismantling regardless then. Yeah I'll investigate the pcv's as well, and if it turns out to be stem seals I'll probably replace them with Ferrea seals. How common of a problem is it to have to replace the stem seals?

[t.mcginley.jr]

Valve stem seals wear out and become loose, therefore letting oil get past them and into the cylinders. It's 100% caused by age/use. So if your car is older (which ours are) or has high mileage then it's very likely they're worn out. Viton also makes good valve stem seals.

[StigZXTT]

All right, duly noted. Am I hurting anything in the engine by not replacing them right away?

[t.mcginley.jr]

Just burning oil really. Could also cause carbon buildup on your valves but that happens normally over time anyway.