Do turbos normally 'seep' a tiny bit of oil when they heat and cool? (80LT1?)

[Guest bastaad525]

Well this isn't Z related, just a general turbo question.

 

Is it usual for a regular, non ball bearing turbo, to seep a little bit of oil into the compressor OR turbine housing, as it warms up from cold to normal operating temp, or cools back off?

 

Here's the situation. On my SRT-4, I have noticed some oil buildup in my intake pipe, only around the turbo inlet. There is also sometimes some oil on the inside of the turbo inlet as well. I've discussed this with SEVERAL knowledgeable people on the board who also have noticed the same thing on their cars from day one, and all agree it can ONLY be coming out from inside the compressor inlet.

 

I've discussed it with one 'dodge guru' over there and he said it's normal, and is caused by the fact that the compressor and turbine housings, and the actual shaft, are made of different metals, so they expand and contract at different rates, and as such, do not always form the perfect seal they should when at normal operating temp. So, some oil seeps out.

 

Having only ever owned one other turbocharged car, my 240z, I do know there always seemed to be a light oil film coating the inside of the outlet pipe from the turbo, but having removed the stock 280zxt rubber boot that connects the turbo to the air flow meter several times, I can't say I ever noticed any oil film in there.

 

Anyways, I called a Dodge service department, and they said that it was normal and they wouldn't do anything about it (why am I not surprised?).

 

So what do you guys think? Is this normal? Does everyone get some oil seepage? I highly doubt it's a defective turbo, unless they were produced defective en masse... because a LOT of people on srtforums.com have this happen to them.

 

80LT1 - if you happen to see this thread, I know you work on some SRT's.... have you noticed this as well, do you agree with this theory, or what's the deal?

[iaconsultants]

Actually you should not see any oil at all, but when you do it means that the bearings/bushings are wearing to much and you will be rebuilding the turbo in the future. With stock turbos or buying lower quality (cheap turbos as I would call it) you can end up with that much quicker or from the beginning due to poor design. Check your impeller for play. Since you probably do not have a run out gauge you should try moving it back and forth with your fingers, if you think you can feel some movement then you know it is worn. Turbos only leak oil or cause smoking out the exhaust when they are starting to go out or they have gone out depending on how much smoke.

 

About the different materials, lets say they used a oil light bronze bushing and you have a carbon steel shaft, well the fit of the two together with tempertures will expand each in different amounts. Designers for turbos realize this and the tolerance of the gap between the shaft and the bushing is always tight enough to restrict oil from boing through at either cool or operational temperatures. In most cases it is tight enough to keep air from going through which has to do with oil surface tension and the tolerance and allowable gap between the impeller shaft and the bearing or bushing.

 

If you are having problems burning up turbos or creating varnish of bearing or bushing surfaces that lead to oil leakage, well then you should invest in a better oil cooling system for your turbos. You could use an electric pump that has a time shut off, you could use a gravity feed lubricator, or you can idle your car after a hard run for a bit to cool it down. You just do not want to cook the oil around the bearings or the bushing because then you get a carbon like varnish type of deposit which makes your impeller run not true to its intended axis by even a thousands of an inch and you will end up causing irregular wear.

 

Just look at all the old Trans Am turbos that there where and they had really no way to cool down the bearings/bushings of the turbo, well you will not find those stock set ups anymore because of the poor design. Factory turbos are generally designed so poorly that they will not last. Diesels are a bit different because simply the fuel and how much unburned oily fule comes out of the exhaust manifold actually helps lubricate some so they last longer in stock setups.

 

Sorry about the long info on turbos but I have been doing turbo and supercharged cars for more than 20 years and have destroyed a few but many successes.

[Guest bastaad525]

well here's where it gets interesting. #1, none of us that discussed this over at SRT forums have ever seen any abnormal smoke out of the exhaust from this, though ALL SRT-4's are well known for the amount of carbon they do build up on the tail pipes.

 

#2, there are guys I spoke with with over 60,000 miles on their car, that had noticed oil in the intake pipe near the turbo inlet within WEEKS of buying the car new, but now years later at 60,000+ miles their stock turbo is still running strong, no problems

 

#3, we had ALL panicked when we noticed this oil initially and assumed the worst.... worn shaft bearing. So we almost all had gone and checked for play in the shaft as soon as we noticed that oil, and all are saying theirs have no shaft play.

 

These are mitsubishi turbos, for what that's worth.

 

And I personally noticed this oil I believe on the third or fourth day of owning the car... yes I was pulling the car apart that quickly and I can't feel ANY sort of movement (other than spinning, of course!) with the shaft at all. Just the oil... which hasn't seemed to get better or worse after now having nearly 7000 miles on the car, by the way.

 

all your info was appreciated but keep in mind we are talking a factory turbo car here where nothing has been changed in regards to the turbo, it's cooling or lubrication systems (that I know of in any of the cases of the people I've talked to and definately not on mine). So whatever flaws are there is in Dodge or Mitsubishi's design. Doesn't seem to shorten the life of the turbo any (there are guys with over 100,000 miles on the stock turbo), though I dont' like the idea of all this oil getting processed thru the entire intake tract.

 

Funny thing though, when I pulled off the hose that connects the turbo to the intercooler (I pulled it off at the I/C... WAY hard to get to it at the turbo), I saw NO oil had made it that far, so should be none in the I/C from this... at least... not yet!!

[Clifton]

Recurculating blow by back on a turbo car seems to make more of a mess, at least on all of mine. On my truck and Z, I vented to atmo and my oily messes went away. I had oil in front of the compressor and in the outlet also.

[240ZR]

Off topics... BUT NICE Rims Clifton are those Ferrari Knock offs?

 

Take it to the dealer... you haven't voided your warranty yet have you? whine... see if they will "fix it" or see if you can get a decent explanation from them..... that way if down the road it eats **** you can come back and state you had a concern earlyer

[Thumper]

From what you are describing bastaard it sounds like a very common problem on srt's. Especially if you have aftermarket intake or raise the boost. What you need to install is a catch can coming from your valve cover breather into your intake tube. The baffle plate inside the valve cover was not designed big enough so at high boost it tends to let oil seep through. This will cause your intercooler pipes to get oily, spark plugs to foul sooner, and black all over bumper. It is coverd many times on srt forums. You can buy polished ones for $90-100 or you can do-it-yourself for $20. When people install the catch cans they usually see about a teaspoon every week or two in there.

[Clifton]

Off topics... BUT NICE Rims Clifton are those Ferrari Knock offs?

 

 

Thanks. They are 5Zigen's.

[Guest bastaad525]

From what you are describing bastaard it sounds like a very common problem on srt's. Especially if you have aftermarket intake or raise the boost. What you need to install is a catch can coming from your valve cover breather into your intake tube. The baffle plate inside the valve cover was not designed big enough so at high boost it tends to let oil seep through. This will cause your intercooler pipes to get oily, spark plugs to foul sooner, and black all over bumper. It is coverd many times on srt forums. You can buy polished ones for $90-100 or you can do-it-yourself for $20. When people install the catch cans they usually see about a teaspoon every week or two in there.

 

Actually I've already got a catch can installed between the PCV valve and the intake, the other side of the valve cover suckes in fresh air from the air filter box... no oil has come out from there. Also, if oil were coming from there there would be splatters at the other end of the intake pipe as well.

 

When I posted a poll on srtforums, this problem definately was NOT only specific to people with aftermarket intakes, and even the guys using a catch can on BOTH hoses out of the valve cover still had this problem. Even the guys who disconneted that vent line and just ran it open with a breather filter still had oil buildup in their intake pipe. Which is why we all came to the same conclusion... it has to be coming from the turbo itself.

[Guest bastaad525]

*bump*

 

no one else with any ideas on this or who have seen this happen on other turbos?

[Guest bastaad525]

*bump* annnnnnnyone else???

 

Has anyone ever seen other turbos do this?