mtheumer

I hate to necro-post, but I am having this very issue right now and it doesn't seem the solution is very clear.

mickey13

if your engine is not leaking oil visibly... that is you dont see any oil leaking underneath, on the sides or anywhere and the engine is just consuming oil....

you should probably think about a new engine.

mine was consuming 3/4 of a quart at every gas fill. there was no oil under the car, it was not leaking anywhere, just consuming oil. my engine was under warranty by Fort Washington Mercedes Benz in PA, USA. They refused to fix it, claimed it was normal for an AMG to consume that much oil. I brought it in maybe 12 times and they would just top it off and send me home. I wrote MB of USA a nasty letter and the dealership asked me to bring the car in. At that point I said FY. Drove it with the oil consumption for maybe 18 months before I decided to swap a 5.4 in for the second time. Still have the first one, never completed the rebuild so never used it.

more likely than not, your rings are letting oil slip through, it could be carbon build up (wishful thinking) or it could be a broken ring or it could be worn rings or it could be worn cylinders. a repair is going to be expensive. if you have the tools, do the swap yourself or do it with a friend. used 5.4 engine can be had for as little as $750 (maybe less) up to a couple of thousand, the swap will take a day or two.

use search on this forum, everything you need to know is here.

mickey13

heres a good article about it as well. it talks about valve guides which i guess might be a cheaper repair but not sure that it would be cheaper than just putting a new engine in.

http://www.aa1car.com/library/oil_consumption.htm

Sulaco

At one point I thought my original 4.3 motor was eating oil. It had just about 300k miles on it so it wasn't shocking.

But it turned out to be leaking in a way that it didn't leak sitting still, it only leaked while in motion so the wind was carrying the oil away but it wasn't making spots in the garage. One clue was a giant puddle of oil underneath my intake on top of the engine block. I cleaned it up and ran it for a few weeks. The oil in that puddle was roughly equivalent to what was missing from those few weeks of driving.

But I also needed a timing chain, so I just dumped in a 5.4 motor.

But anyway mtheumer your tag has a CLS 55 AMG. Is that the motor you're talking about?

mickey13

that is really interesting. i still have my 4.3 and expect to one day have enough room to tear it down and see what the issue really was. before i threw it in storage it looks filthy

benzslo

If your engine is consuming oil, it it 99.9% that it's from your rings. Known issue with all the m112 and m113 engines back in the day to anyone in this industry.
Problem was trying to go 10-13k miles on mineral oil in the 98-99 years. Oil would not hold up, sludge up and stick the rings. They'd run great but would consume lots of oil. I've seen hundreds get repaired and personally done dozens. New Pistons and rings and often times a new block. There was a big class action lawsuit and warranty extended to 150k but time-wise that is done and gone. Didn't see it on the AMG's as much because they were always supposed to get synthetic, but that doesn't mean someone didn't run mineral oil in it or went way too long between changes. Anything is possible but I've been doing g this a long time and have seen this scenario hundreds of times but have never once seen an m112/113 with head gasket or valve train issues, not once. And I'd be very skeptical of anyone claiming so, I've also seen alot of mis diagnosis from backyard shops and forum followers, they are the worst.
I'd personally use this as an opportunity to replace with the 55 motor. Or if you're real short on funding, get an old 43 motor from someone who did the swap. They're only worth about a case of beer. Hell mine is collecting dust in my garage because nobody wants it, 70k miles mint. I'd give it away if you were close.
If you do a motor swap, try to get one with known history, or cross your fingers. On my 5.4 I took it all the way down replaced rings, sonic cleaned pistons, new bearings, new everything. Not necessary but getting one from an owner is better than a junkyard where you don't know the history.

DRBC43AMG

Amen to that

Futureal

Great post. I currently have a 2016 GL350 that is burning oil like a mother#$%^&. I have had MB dealer do an oil consumption test June 2021 and it failed it, so they replaced the turbo but the car still burns oil. Did another oil consumption test October 2021 and tech said it was 0.1 away from failure so couldn't do anything. Right now what I am dealing with is after June 2021 turbo job, tech created several leaks on top of the engine, one of which I eventually found by myself by removing the air filters and by closely inspecting fuel injectors I found drivers side injector leaking. At the same time car went to in limp mode so I made an appointment at the dealer and they told me needs new DPF filter and obviously new fuel injector seals (dealer just replaced the fuel injector) Currently dealer claims they fixed all engine leaks. When I started to tell advisor that the reason DPF got clogged is that engine throws too much oil down the exhaust and that DPF will need to be cleaned or replaced soon, he just ignored me, I get this feeling that the warranty is willing to fix everything around the engine but now willing to replace it. I am going to try another dealer for oil consumption test in the orange county area and see if they are willing to work with MB warranty on engine replacement. I found another post here on MBworld where original poster basically purchased remanufactured engine from MB dealer for around $9000 and put it in himself to resolve excessive oil consumption. In my situation I will try warranty route again, if not I will hire a lemon law attorney and will go that route ( I am still under MB Extended Warranty), worst case I will just buy remfg engine from MB and have a friend help with engine swap. May be I will take that engine you have laying around in your garage lol