Oil in Intake

[cammmy]

Hi All

Taking apart the intake to check the filters, I've noticed a decent amount of oil in the charge pipes. Is this normal or likely to be some kind of PCV/(God forbid) turbo seal failure?

These pics are from the R/H pipe (when in the car facing forward) and while there's oil on both sides, this side seems worse

Ta
Cam

[Jim Haseltine]

I think you need to take a look in the inter cooler pipes. I'd advise a big plastic sheet under the car and a capacious container to catch any oil in the pipes because the stuff goes everywhere.
I only once measured what I got out, a good 750ml from the right cooler if I remember correctly. I spent a fair amount of time chasing the cause which eventually turned out to be the turbos but on the way I discovered that the PCV diaphragm in the oil separator was holed (unlike some VAG units, not available as a part) and two of the three breather non-return valves were locked open.

[cammmy]

Righto, thanks. Is that a bumper off job?

I hope it's not the turbos but I guess that would solve the questions about whether to upgrade them when having the oil pump seal done.

[Jim Haseltine]

No, just the under tray. RH hose is easy, LH is more difficult because the fastener for the hose clip is well hidden. It's only bumper off if you need to take the inter coolers off to drain them down and you'd need a lot of oil in there for that.

Edit: Found my thread from when I started to chase my oil burning problem:
viewtopic.php?f=47&t=131735

[cammmy]

Thanks, I just had a read. I also found Ian's training doc. The fact that the PCV vents into the intake both upstream and downstream of the turbo makes diagnosis more difficult. I haven't noticed any smoke from the exhuast, I only spotted this as I was checking the air cleaners.

I guess she's going back on the lift then. I'll pull the intercooler pipes and see what's in there. I'll also pull the PCV valves and check they are doing their job.

As an aside, I thought one of the advantages of a dry sump was that you could pull a vacuum in the crankcase? I'm surprised there is a seperate PCV system coming from the cylinder heads.

[cammmy]

Another thought, if the check valves are dead, it could well be dumping boost into the crankcase?

The training doc seems to suggest the the gas from the L/H bacnk go through the fancy setup in the oil reservoir, but the R/H bank just goes through the fine seperator and then straight into the cylinders. Why setup a really fancy system for one bank and then have the other totally bypass it?

[Jim Haseltine]

Another thought, if the check valves are dead, it could well be dumping boost into the crankcase?

As two of the check valves are connected just in front of the turbos I think you'd only get boost in the crankcase if the centre (inlet manifold) check valve and the PCV diaphragm were duff.

[cammmy]

Fair enough. Thanks

[cammmy]

Mostly for my own future reference if I need it, but there's some info on the turbos here:

http://australiancar.reviews/Audi-RS6_BUH_Engine.php

IHI RHF55, part numbers:

07L 145 701J
07L 145 702J

[Jim Haseltine]

Well they're close but no gold star. Yes, they are IHI RHF55 turbos (type VVA1 to be exact) but they are not ball bearing turbos. I've yet to find another road engine that the VVA1 is used on - I've a suspicion that it's used on earth moving machinery but can't get any confirmation on that.

[welwynnick]

VVA1 quite likely refers to the intake and exhaust housings that are unique to the RS6. The centre housing & rotating assembly is quite likely shared with other cars, and that´s the important bit. Which other cars? Not a clue, sorry.

[Jim Haseltine]

The impeller is used by quite a few other RHF55 turbos. As for the centre housing and the turbine, I've had no luck matching them with any other IHI turbo so far. The bearings, thrower plate and seals are bog standard RHF55 items.

[cammmy]

Thanks. I found your link to the rebuild kits for them in the turbos thread.

My issue is that if I go the DIY route, I do have a lift and I built the garage to fit the RS, but not the RS and an engine crane. With the roller door closed, I can only go through the car or under it.

[welwynnick]

You have a lift in your garage?

Well, you must be one of those people like Jim who can do anything then!

What sort of lift?

Nick

[Jim Haseltine]

How many times have I dreamed of having a lift.... Still, there's always a chance of 6 numbers coming up.

I was lucky as in being able to take a week or so leave from work with excellent weather when taking the turbos off. Having said that, I only had the engine on the crane for short periods - I became pretty proficient at dropping the motor, moving it around a bit then jacking it back into place when I needed to break off, once you've got the subframe off and the suspension strapped up out of the way it's not difficult. Unless you can get the engine completely out of the car getting access to the many and varied pipes connected to the turbos is a logic exercise - disconnect this clip with the engine in place, drop it by an inch to get to that clip, no that's too far, lift it a bit, now drop it further to release this. As for putting it all back... well, I'll just say that quite a few strops were thrown as were a number of tools.
Mine is a 1960s garage, even if I'd been able to put the RS in there I'd not have had anything like enough space to do the work - I suspect that I wouldn't be able to open the bonnet fully with the car on stands as the head room is only around 6'6" with the door open. The 'official' way to do things is to support the engine and then lift the car away from it.