2.0T Engine Rebuild??

[willssss]

Hey everyone, need some advice and/or opinions.

Recently I've had some issues with my manual trans 2007 A4 Avant (with 137k miles on it): trouble starting, EPC light, and CEL. I ran some codes which indicated I needed a new N80 Valve and Fuel Pump. I replaced those and things have been running better (dash lights are gone) but I felt like I was down on power. Decided to take it into a shop to get it looked at to run a compression test and while I was there I happened to mention I was burning oil at a rate of about 1 quart per 1000 miles.

Without skipping a beat, the mechanic (a very well rated, and experienced VW/Audi guy) said I needed an engine rebuild. WHAT?? Yup, according to him (and research on the interwebs) the 2.0T has a design flaw in the piston rings that results in burning oil which gets worse over time till the engine fails.

Has anyone else had this experience, had their engine rebuilt, or had their engine fail on them as a result of burning oil? Do I follow his advice?

I am not quite sure what to do, I bought the car for $5500 (with 75k miles on it), and for fun have thrown about $5000 into it not to mention have more parts in the basement I want to put on the car. Not only that, but the used car market is a total shit show at the moment, and there are no interesting wagons with MTs that I want to drive. Do I bite the bullet and rebuild the engine or sell the car, and find something else?

Any thoughts or advice?

Attached is a picture of the car for your viewing pleasure.

CC361DF9-788E-4A3C-9FEC-94FB406772D7.jpg

[mr_Law]

I feel you, I just put 5k into mine as well. Not to mention the add ons.
How much are they quoting the rebuild?


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[willssss]

At least $5k. Not to mention the huge desire to upgrade the turbo while the engine is out

[Jayz691]

The b8 more commonly has thise issue, with pistons/rings. Not saying it can't happen. But have you checked all the normal culprits? Pcv, cracked VC, etc? Check your IC hoses for oil. Maybe leaks your not aware of? Many things to check before coming to the conclusion of "engine rebuild". Curious if he did a compression test, although that won't show oil ring condition.

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[willssss]

I took his word for it, so I am happy to look around at other issues that could be causing the issue. He did not end up doing a compression test.

I had thought to look into replacing the PCV valve or getting a catch can instead. I will do more research into that and check the IC hoses as well this weekend if it ever stops raining.

[aluthman]

If the extent of his “diagnosis” was hearing you say it burned oil, get another opinion.

[willssss]

He actually was my second opinion, the first opinion said I needed a new turbo. In both situations they "have seen this happen with these engines all the time". I trusted the second opinion more based on what I have heard about the quality of the shop and their work.

I'll get another opinion. From what I can tell though, there are no obvious drips and from checking the spark plugs (I know thats sort of an outdated method) they appear black. If I do have a bad PCV, would it leak oil into the cylinders causing it to burn?

[Brillo]

If I do have a bad PCV, would it leak oil into the cylinders causing it to burn?

Probably not. The only common sources of oil into the induction system are a leaky PCV passageway underneath the VC or failed TC compressor seals allowing cooling/lubrication oil to be pumped into the IC piping. Failed TC turbine seals will leak oil directly into the exhaust system where it will get burned and not contribute to blackened spark plugs.

If the VC passageway is cracked and sucks oil into it, the oil will descend through the breather tube (on the right side of the VC), through the compressor into the IC and IC piping then into the IM and on into the combustion chamber.

If the diaphragm valve in the PCV valve is not functioning properly and you have cracked VC passageway the vacuum in the IM (under non-boost conditions) could suck oil into it and then on into the combustion chamber.

The third source of oil consumption as mentioned above are clogged oil control rings. The narrow rings used in these engines can get clogged up due to low quality oil and/or excessive oil change intervals, and fail to drain the oil scraped from the cylinder walls through the ring and on into the drain holes in the bottom of the oil ring piston grooves. Therefore, the excessive oil retained on the cylinder walls will get burned in the combustion process. If it is bad enough an engine rebuild is necessary to correct as you learned from your shop tech.

[esandes]

Do a leakdown test to be sure it's the piston rings. I agree with jayz691 but a leakdown result could save you on buying a new PCV and valve cover gasket.

I had the same problem and replaced the engine with a rebuilt one. The oil consumption got worse over time on the original engine. The rebuilt one has been great....and still is <knock on wood>

[Theiceman]

A leak down test is a waste of money and will tell you zero about the oil scraper rings. Don't do this.
I would remove and inspect valve cover first..


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[Jeevan]

it could be anything out of these- oil rings, valve cover, pcv, leaking valve guides/seats.


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[Brillo]

A leak down test is a waste of money and will tell you zero about the oil scraper rings. Don't do this.
I would remove and inspect valve cover first..


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Theiceman is correct. A leak-down test will tell you nothing about the oil control rings. Don't waste your money or time.

[willssss]

A leak down test is a waste of money and will tell you zero about the oil scraper rings. Don't do this.
I would remove and inspect valve cover first..


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Yiokes. Removing the valve cover strikes me as a touch above my pay grade...

I did decide to order a Catch Can (it's been on my wish list, and I apparently like to throw good money after bad) but it wont be delivered till Mid-April. So I wont know if that makes an improvement till then. I have noticed that when my oil cap is off, the car runs like crap, which from what I've read in other threads is an indication of a bad PCV. Is there any way to know if there is a cracked VC without removing the VC entirely? Is oil residue inside the Breather Tube an indication of a cracked VC?

it could be anything out of these- oil rings, valve cover, pcv, leaking valve guides/seats.


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Sounds like if there are bad oil rings, or leaking valve guides/seals these could be pointing to engine rebuild territory, no?

[Theiceman]

well if replacing a valve cover is above your pay grade with all due respect i would not be changing factory parts without understanding the impact. a catch can will gain you absoluetely nothing with this car and will only complicate issues..

removing the oil cap and having it run rough is perfectly normal as you have created a massive vaccum leak. it is absolutely no indicator of PCV health

valve guides and seals are rock solid on the many Audis I have driven and serviced and there are almost zero reports of it here.. in fact i dont think i've seen one for years.

The rings are definitely possible but as pointed out it is more common in the B8.

yes you can test the channels on the valve cover but if removing a few bolts in the valve cover is over your head, so will the diagnostics be to check this. A " competent " mechanic when you tell him you have high oil usage in your model should first detach intercooler tubes nd see how much got dumped in there , then take 20 minutes to remove and check valve cover... If he doesnt do either of these two or mention them to you he does not know this car well and find another mechanic.

[esandes]

The iceman has no clue what he's talking about.

[Theiceman]

The iceman has no clue what he's talking about.

ummm okay ..... how many engines you rebuilt ? let me guess zero ?

do you even know the difference between a compression ring and an oil scraper ring ? i wish you would stop posting as you make us Canadians look like idiots.

[willssss]

removing the oil cap and having it run rough is perfectly normal as you have created a massive vaccum leak. it is absolutely no indicator of PCV health

valve guides and seals are rock solid on the many Audis I have driven and serviced and there are almost zero reports of it here.. in fact i dont think i've seen one for years.

The rings are definitely possible but as pointed out it is more common in the B8.

yes you can test the channels on the valve cover but if removing a few bolts in the valve cover is over your head, so will the diagnostics be to check this. A " competent " mechanic when you tell him you have high oil usage in your model should first detach intercooler tubes nd see how much got dumped in there , then take 20 minutes to remove and check valve cover... If he doesnt do either of these two or mention them to you he does not know this car well and find another mechanic.

He does not know the car well because I have done all major work myself (with the exception of the timing belt). To be fair to myself, I dont know what is involved with removing the valve cover, so maybe I was premature in saying it was above my pay grade. Just sounds a bit nerve wracking if I am exposing the cams, followers, etc. I haven't looked into it though, so I dont know for sure. I would love some insight on removing the valve cover though, if anyone is up for giving it. Otherwise, Ill just look it up.

Edit: Looked it up, does not look very difficult.

[Theiceman]

He does not know the car well because I have done all major work myself (with the exception of the timing belt). To be fair to myself, I dont know what is involved with removing the valve cover, so maybe I was premature in saying it was above my pay grade. Just sounds a bit nerve wracking if I am exposing the cams, followers, etc. I haven't looked into it though, so I dont know for sure. I would love some insight on removing the valve cover though, if anyone is up for giving it. Otherwise, Ill just look it up.

Edit: Looked it up, does not look very difficult.

Perfect . It is not difficult at all as you have found. Just be patient getting the hoses off and grab a new gasket.. it is actually very rewarding. If you have any questions just post them here...
When you get the cover off flip it over.. look very carefully for areas you can lift up. See if you can pressurize the channels in the cover and see if the sections lift up.
If so it's done and is sucking in your oil.
I would spend money on a new valve cover before I would spend it on anything else.
Brillo posts a great article occasionally showing how it works.

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[Theiceman]

Oh when I said he does not know the car well I meant the b7 model and the biggest failure points..not your particular car..
If you talk to a mechanic and he mentions these things. He knows the b7 very well and you can be comfortable.

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[willssss]

Oh when I said he does not know the car well I meant the b7 model and the biggest failure points..not your particular car..
If you talk to a mechanic and he mentions these things. He knows the b7 very well and you can be comfortable.

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Ah, right. Thanks for clarifying.

After a bit of research it appears that if there is oil on the coil pack it is an indication of a bad gasket, which there definitely is, so I have ordered a new gasket. When I replace it I will take a look at the cover for cracks in pressurized channels.

[Jayz691]

The iceman has no clue what he's talking about.

What?? Hes 100% correct on his entire statement..

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[Jayz691]

Ah, right. Thanks for clarifying.

After a bit of research it appears that if there is oil on the coil pack it is an indication of a bad gasket, which there definitely is, so I have ordered a new gasket. When I replace it I will take a look at the cover for cracks in pressurized channels.

The main channel to be concerned about is the one from the front pcv port to the rear breather(metal tube to turbo inlet). Thats the main culprit. The other passage is for you n80 and will more cause a vac leak, than sucking up oil, but it may be possible. Good luck with it.

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[Theiceman]

Ah, right. Thanks for clarifying.

After a bit of research it appears that if there is oil on the coil pack it is an indication of a bad gasket, which there definitely is, so I have ordered a new gasket. When I replace it I will take a look at the cover for cracks in pressurized channels.

There is a definite caveat here. If the gasket does not fix the oil in the spark plug holes don't be discouraged. There is another area called the cam cradle under the cam cover that leaks oil into the spark plug holes.
That's a big job so start with valve cover gasket.

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[willssss]

Replaced the VC and VC gasket over the weekend which was so painless that I decided to punish myself and install the high flow cat I had laying around. The down stream O2 sensor wouldnt budge so as a result I am waiting for a replacement while my car is still on jack stands. Needless to say, I havent gotten a chance to drive it since.

Image from iOS (13).jpg

That said, the VC and gasket both looked in pretty good shape and nothing appeared cracked or damaged.

Image from iOS (16).jpg

Something I did notice was what looked like oil at the back of the engine just over the cat:

Image from iOS (15).jpg

Another point of reference is what looks like oil on the intake tube just past the air filter:

Image from iOS (14).jpg

I still have to take a look at the IC hose, but really the thing that worries me is the oil on the back of the engine... is a new cam cover gasket in my future?

[Jeevan]

oil at the back of the engine is from leaking timing cover on the back of the head or the vaccum pump leak.

Valve cover may look fine on the outside but it doesnt mean that the pcv passages inside the valve cover arent fkd and crumpled.

you need a crowfoot wrench(can get them in autozone) to remove post cat oxygen sensor.


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[willssss]

Yeah, I have a crowfoot. I've attacked it with my with my 2.5ft breaker bar and destroyed the threads. It is not coming out.