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Turbo Disaster Incoming?

Help, Advice, Owners' Discussion and DIY Tutorials on Volvo XC90s. The XC90 proved to be very popular, and very good for Volvo's sales numbers, since its introduction in model year 2003 (North America).
vcsuri
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vcsuri

Turbo Disaster Incoming?

Post by vcsuri » Tue May 19, 2020 4:09 pm

Hi all,

Ongoing issue on my 2005 XC90 2.5T (175K miles).

I recently discovered my turbo upper intercooler hose (PN 31261369) was completely degraded and covered in sticky oil material. I replaced the upper intercooler hose with the OEM part, and used brand new clamps.

After a week of very little short distance driving (1-2 miles at a time), I am already noticing a build up of oil in the same location (where the upper pipe meets the main intercooler pipe). I have no loss of power from the powertrain, and the turbo sounds fine for now.

Can this be a sign of future trouble approaching?

PS: PCV components were replaced at the same time as this intercooler hose (2 weeks ago), and the carbon buildup in the PCV box was not alarming.

chitownV
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chitownV

Re: Turbo Disaster Incoming?

Post by chitownV » Tue May 19, 2020 5:07 pm

Is the new hose caked in oil or do you just notice there is oil?

Ensure the hose clamp is on there tight. At times, rubber hoses need a re-tightening after going through a heat cycle. I noticed that it can be a little difficult to tighten with just a flathead screwdriver, especially since an aftermarket hose with the fixed clamp gives a difficult angle. So, I used a 1/4" 7mm socket to tighten a tad bit more.

If there is a lot of oil, this could be a sign of a bad oil seal in the turbo. To further investigate you can remove the turbo outlet rubber hose (up top, rear) and inspect the hose as well as get a phone back there to take a pic of the inside of the turbo to check the condition.

vcsuri
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vcsuri

Re: Turbo Disaster Incoming?

Post by vcsuri » Tue May 19, 2020 6:04 pm

Thanks for the reply chitownV.

Previous hose was caked in oil. I'll try re-tightening the clamps on the new one.

If the turbo oil seals are bad, are they replaceable, or does the turbo need to be replaced?

Thanks for your knowledge, I'm still learning the ropes with Volvos.

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SuperHerman
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SuperHerman

Re: Turbo Disaster Incoming?

Post by SuperHerman » Wed May 20, 2020 1:10 am

The magic turbo oil seal is nothing more than a split washer (highly machined and sized) - basically like a piston ring (it is referred as such). It is no bigger than a dime in diameter, slightly thinner in each other dimension.

Basic explanation - the turbo shaft (turbine shaft) has the exhaust fins on it by design. On the opposite end is a compressor wheel attached by a nut. In the middle are all sorts of other parts that get gunked up and wear, but nothing one can do about them until rebuild time. Exhaust is where the original spooling power comes from intake (compressor wheel) is where the air is pushed into the intake which creates the boost. The turbine/shaft spins from combustion exhaust and the compressor wheel spins as a result as the two units are joined by the nut. To keep the unit spinning freely it rides on journal bearings which are lubricated and cooled by oil (further cooling by normal coolant, but this is an isolated circuit). The oil passage from exhaust side to intake side is controlled by the piston ring. Over time this piston ring starts to wear and allow more oil to pass through into the intake side. (Unlike a cylinder piston ring which goes up and down, the turbo piston ring only rotates) At the same time the journal bearings also wear and the turbine shaft starts to wobble which results in greater wear of the piston ring.

Oil passage (leak) is normal, when it gets bad the engine will smoke out the exhaust - this is usually when one services the turbo unless it is making noise.

I would check your PVC system and related hoses for air leakage as this could draw in unwanted air creating pressure differentials which may cause your symptoms. At 175k it wouldn't be unheard of for a turbo to see end of life, but some have gotten 300k on them.

To examine the turbo one needs to do some major surgery and at that point the play one can feel is not really determinative. Further if you are going this distance you may as well rebuild the turbo, not that expensive and plenty of write ups, or buy a complete turbo cartridge and plug that in to the housing.

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ggleavitt
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ggleavitt

Re: Turbo Disaster Incoming?

Post by ggleavitt » Wed May 20, 2020 8:01 am

I have a fully functioning 5 cylinder and have replaced the upper intercooler a few times in 200k miles. Gets constant oil vapor on the inside, eventually sweats it to the outside. Guy in Europe went all silicone for the intake and now his hoses are clean on the outside. Oily intercooler hose is somewhat normal in my opinion, do an internet search for "volvo turbo intercooler hose oil" and you'll see what I mean. Can see this post-https://forums.swedespeed.com/showthrea ... 0-AWD-2-5T, looks like I started replacing the hose at around 100k, on my third one now and engine consumes around 1qt/4k miles (has been relatively constant over the years). For this hose you can buy a cheaper model (think I have URO on now), it's gonna get greasy again.

I have a turbo rebuild kit on the shelf since last year, intending to pull the cartridge and do all new parts because it's something I want to do on the '05 (200k miles) along with a "scheduled" PCV service and t-belt. When I complete the rebuild and if the leak goes away, I'll re-post.

Barring an engine performance issue or excessive oil consumption, you might just leave the hose and watch it for a while, see if things get any worse. If it's somewhat constant, replace the hose when it looks crappy (again).


edit 052020- Drop PCV and new hose reference, see work was already done.
2005 2.5T AWD-200k
2008 V8 AWD Sport-130k

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