mcperreault

Hello All,

I originally posted this in a different forum but an experienced AudiWorld member gave me some things to look at and suggested I re-post it here with test results for better/more advice.I have searched the internet and various forums and cant seem to find a discussion that matches my particular problem. I have a 2016 Q5 Premium Plus with the 2.0T that started using oil at about 75,000 miles, and at about 82,000 miles and it was consuming oil at about 1 quart every 1000 miles, and it seemed to be getting worse. The twist here is that the only thing that appears to be wrong is that it is consuming oil. There are no codes, it runs great, there is no smoke, no noise, no drivability issues at all. The vacuum in the crankcase appears to be normal - a slight sucking from an open oil fill cap at idle, which lead me to believe it was not the PCV. I have a pristine garage floor and there are no leaks. No evidence of leaking oil from an underside visual inspection either. Cosmetically, the formerly chrome tail pipes are now a carbon black. I did a leakdown tests (worst cylinder - #3 was at 6%, lest than 5% for the others). I replaced the PCV because it was convenient and a possible source of the problem.. I looked at the turbo piping and found the exhaust piping had an oil sheen but no evidence of the "oil lake" in the intercooler piping that others have experienced. Since that original post, the car is now just past 85,000 miles and used a quart at 83,350 and another at 84,711 miles. The car still drives great - no smoke, no stuttering, no driveability issues - only this oil usage and the blacked out exhaust tips. No problems anywhere, at least until I looked in the owners manual. Per the owners manual, the engine can be expected to consume a 1/2 quart every 600 miles, and even more when new! Which is what a dealer said when I took it in. Because the oil consumption has stabilized at just above the 600 mile per half-quart spec, I think this is a known and accepted condition for this motor. Which leads me to two questions:

1. Does anybody have any thoughts or ideas on what this problem might be that I haven't looked at? They would be greatly appreciated.

2. What is the trade-off, in particular what am I getting for the increased oil consumption? Without a good explanation, I'm not inclined to think its worth the hassle, and although I'm a fan of Audi in general (there's a 2018 Q7 in the garage and a Q8 in the works), I don't think I would ever purchase a vehicle with their 2.0T motor again.

Thanks

S4'ed

Try replacing your PCV unit, about $160 and 20 minutes to change it. Make sure you buy the latest revision of the genuine VW/Audi part, not some cheaper aftermarket clone part.

If that doesnt work, then it is likely the oil drain holes of the oil control ring spacer, and the oil drain holes in the piston, behind the oil control rings can get clogged, causing the oil consumption issue. The solution is to try to desolve the clogging deposits with some extended soaking using an upper cylinder solvent, but if that doesnt work, the rings and pistons need to be removed, cleaned, or replaced.

Your oil consumption will get worse.....I got to about a quart every 300miles before I dumped the car. If you like the car, fix it, otherwise sell it, it is probably not worth a full engine disassembly or replacement.

Bob Petruska

He did replace the PCV valve.

apoelistas

Is the oil control ring spacer a different name for piston rings??when you service the piston you change all 3 and probably this is the answer but still does not make sense bcs this is not a 2009-2013 my Q5.

S4'ed

The spacer sits between the 2 oil control rings.

mcperreault

so I am inclined to fix it, and I am not adverse to pulling the engine. Do you think a clean and replace of the existing pistons will work or go with new OEM pistons?

S4'ed

If your compression looks good, and the cylinder bore diameters/roundness and ring-gaps measure within spec, then you could just clean and reuse your original pistons & rings. Also, check the pistons carefully for cracks near the top edge and the ring grooves. But make sure you don't mix-up the pistons, rings, and bearing caps/bolts, they should go back exactly where they originally came from. Also, don't flip the rings around.

While you have everything apart, replace all three timing chains, tensioners, guide rails, and the lower timing cover, with the latest genuine VW/Audi parts. Also check for a missing oil filter screen in the cam-bridge. Also replace the rear crankshaft seal, you might want to consider the much more durable aftermarket rear seal from iABEB Engineering. Also, might as well put in a new waterpump on, and maybe a new intake manifold. You will need to buy the timing lock/alignment tool-set for this engine.

iABED Industries - 462-103-171F - Billet Aluminum Rear Main Seal Upgrade (ecstuning.com)

Bob Petruska

I don't believe that reusing piston rings is a very good idea. The current rings are conforming to the the cylinder wall irregularities. When you remove the pistons and clean the rings, reinstalling them back into the cylinders is going to have the high and low spots on the rings in different cylinder wall locations. This will most likely produce a major oil burning engine which the OP was attempting to fix!

simplesez

www.carmax.com

let someone else deal with that nonsense.

silver_tt

Hi, that was me that responded previously. Good you did the OE PCV and leakdown like I suggested. Based on everything you are saying it does sound like the it's probably the piston oil control rings. You are burning the oil as evidenced by the tail pipes. Related to apoelistas' question, there have been numerous reports of 2.0T's up through and including 2016 and 2017 having the older style pre-gen3 pistons/rings (which have small holes that can clog with carbon).

My advice would be to switch to an oil for DFI engines and change oil at max 5K intervals. I realize not everyone would do this but if it was my car I would pull the engine (very easy with this car, one of the great things about this engine) and replace the pistons with the new OE. I agree with the recommendation to do the water pump and the timing chains/tensioners at the same time as they will effectively be freebies with the engine out of the car and the coolant dumped. You don't need to do the intake.

I would be curious to know when you pull the rings if you have waffle rings.

While this job isn't cheap, I personally dont think it's worth getting rid of a car over. A good indy can do this for half what a dealer charges or less. I haven't looked but I'm guessing you can do it for $4K all-in using OE parts at wholesale and a solid indy. My 2.0T is approaching 85K miles and burns zero oil but I'm one of the only people in the community running an oil for DFI engines and replacing my PCV as a maintenance item. This is a DFI issue and ranges from every car manufacturer from Toyota to Porsche -- no exceptions. This is well documented in academic and industry research.

Feel free to PM me if I can help. Good luck.