Blue smoke. Some troubleshooting done. What next?
 

1.6 l with 70k miles . Turbo went on 2k miles ago. Details in the sig plus EWG.

I noticed that after a boosted run in 1st and 2nd, there is a small cloud of blue smoke. In particular when decelerating, i think, but not sure. There is no smoking blue any other time, not when first starting, not ever.

I took out the PCV valve, blocked off the intake end and put a breather on the cam cover side. I checked the other cam cover tube (on the exhaust side) and there is absolutely no oil. I also checked the intercooler tube going into the intercooler and there is absolutely no oil, not even an oil film. The turbine wheel (connecting to the air filter, not the one to the dp) looks brand new with no oil on it. There is no play in the turbo shaft.

Compression: 160 across all 4. A bit low, i thought. So I moved on and did a leakdown test. The leakdown test was repeated 3 times on every cylinder, going 1342 for 3 times. I got 1-3% leakdown across all 4. This was verified at 3 different pressures, 30, 50 and 80 psi.

Any ideas what to do next would be great. Looks like the smoking is getting worse.

Only on deceleration? My understanding is that's a sign of the valve seals going or toast. Mine was smoking for a multitude of reasons, but when asking around I was told decel smoke was a tell tale sign of valve seals gone bad. Just my :2cents:

^ I would tend to agree. If they get bad enough, you'll see blue smoke on startup after sitting overnight.

Since it is only on decell on a boosted run, I would say turbo with oil going to the turbine side, hot side.

On the upper end of the run, oil pressure is the highest,

I would check the max oil pressure the turbo gets, you may need an oil restrictor on the oil feed.

Yes you can feed too much oil to the turbo

How do i check if the turbo gets too much oil/max oil pressure the turbo gets? I would like to be able to verify this before putting on a restrictor to find out that it was something else and in the process i cooked the turbo?

Thanks

APT Turbo. Com has restritors. I got mine there. Drunk sorry for typing. Solves problem yeah. NO maybe valve seals.

So, i am pretty sure it's the valve seals. Is there any advantage to buying aftermarket seals compared to stock?

Thx

get what you can, find the Vition Blue seals, they have the highest temp rating of any of the common valve stem seals

so I bought some valve seals to replace mine. Still need to buy/get the tool to allow me to change them with the head still on the block.

i am still thinking that it could be the oil rings OR the rear turbo seal. Is there any way to diagnose a rear turbo seal leakage without dissasembling the turbo and the chra? just by looking at the turbine wheel??

also, how can i know if the turbo is fed too much oil? i worry about putting a restrictor on the oil in line without knowing if this is the cause for sure. if it isn't, the turbo may get too little oil.

thanks

Mine's smoking at full boost and after long overrun, but no smoke on startup.
I have new valve seals (OEM from Mazda) although the exhaust valve guides are a bit loose. I rebuilt the engine, new rings and bearings, forged rods, block decked, new valve seals, etc.

My turbo is a used 2554r, little shaft play, runs for 8-10sec after shutdown.

Do it replace the valve guides and seals (again) or rebuild/upgrade the turbo?

Self,

Pull the turbo exhaust elbow, Dry= good, Oily wheel = Bad shaft seal or over oil pressure.

The easy way to check turbo oil feed pressure is to T into the turbo oil feed line and hook up a mech. oil gauge.

As far as how much oil your needs, contact the manufacture and see what they say.

Guz.... Yours sounds like turbo also.....

Thanks. By turbo exhaust elbow I assume you mean the downpipe

yes, dropping the DP will work too.