Gurgling noise from oil during BLT

[horizontalkev]

Around 10PSI Im getting a slow gurgling noise from my oil fill hole. I don't have a PVC setup. Is this normal?

And during cold starts my car likes to bog out in boost and in general run bad until warmed up, but can't find any boost/vacuum leaks besides the BISS screw. What else could it be? Thanks

 

[BogusSVO]

Disconnect the oil feed line to turbo, and do the BLT again. If the gurgle goes away you were pushing air past the seals into the turbo and back flowing the oil system.

 

[1qkfwd]

More than likely its the seals behind the compressor wheel. They get old and hard over time.

 

[horizontalkev]

Thanks for the help. Its a T-28 with 3,000 miles on it, however its been on the car for the last 8 years so it may be time for new seals. I will do the BLT again with the oil feed removed. What are the possibilities it could be shot piston rings?

 

[1qkfwd]

Even if you remove the oil feed and the o-rings are in fact bad, you'll still get pressure bleeding off through the drain tube into the oil pan.

Rings you'd need a compression and leak down test.

 

[JusMX141]

More than likely its the seals behind the compressor wheel. They get old and hard over time.

I'll assume you mean the rubber o-ring that goes between the plate and snap ring behind the wheel and not the compressor sealing ring.

These do pose a problem on TD05-style turbos because the o-ring fits into the housing and allows the plate to pass through it; over time the o-ring flattens out and gets distorted. On T25/T28 turbos and others like Holset, however, the o-ring is sandwiched between the plate and housing...the force of the snap ring is what creates the seal, so by design the o-ring is practically leak-proof.

 

[BogusSVO]

The turbo oil drain should be into open air inside the oil pan, so there should be no gurgling.

Also lightly stuff a chunk of clean paper towel in the turbo oil feed on the turbo, when you do the BLT, if air is pushing through the oil feed, it should pop the paper out.

If the rings are shot, you will not get gurgling.

The only time you get the gurgle is when the oil is letting air pass through it, so it has to come from the pick up screen.

Think of a little kid blowing bubbles in his milk with a straw.....

 

[1qkfwd]

I'll assume you mean the rubber o-ring that goes between the plate and snap ring behind the wheel and not the compressor sealing ring.

These do pose a problem on TD05-style turbos because the o-ring fits into the housing and allows the plate to pass through it; over time the o-ring flattens out and gets distorted. On T25/T28 turbos and others like Holset, however, the o-ring is sandwiched between the plate and housing...the force of the snap ring is what creates the seal, so by design the o-ring is practically leak-proof.

I was assuming its a TD05 based on the fact its 6-bolt swapped.

 

[horizontalkev]

Thanks for the help guys

So the air pushing through oil isn't coming from the turbo unless for some reason its not sealing?

The only time you get the gurgle is when the oil is letting air pass through it, so it has to come from the pick up screen.

I should be okay then if that's the case?