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Hi guys, I'm fairly new to the MBWorld forums but have just purchased my first ever Mercedes, let alone an AMG. I got it for a decent price, considering its had its head bolts replaced and had extensive maintenance done to it both at an MB dealership and an indy European mechanic in San Jose. With the long drive back to Houston, TX, I started to notice about 700 miles in a burning oil smell.
I took it to my local mechanic as soon as I got back to Houston and they pointed out a large oil leak, and the wind while driving blew it onto the hot exhaust and as back as far as the rear resonator. I was quite surprised there was an oil leak, considering the M156 had its headbolts replaced, valve cover gasket replaced and valve lifters in July 2020. It had also been upgraded to the deeper transmission pan by FCP Euro (001989680310).
Previous service records also indicate that a mechanic identified a valve cover gasket leak as early as 2019 and recognised motor oil filter housing gasket leak in July 2019 ( at 123xxx miles). Car is now at 137xxx miles. However with these issues recently addressed according to service records, I'm not sure why there's a new oil leak this soon.
I paid the mechanic to identify the oil leak, and they put in a dye and told me to come back after about 400 miles to identify the source of the leak. I've attached photos below. If you guys have any idea what this issue is, how much it'd cost or whether the engine is even worth saving please let me know. I had got a PPI done in SJC but I'm shocked they did not pick up this oil leak up assuming it was before I started driving back to Texas.
Oil seems to be on the back half of the upgraded transmission pan. Mechanic said its definitely engine oil, but was unable to identify the source of leak at this inspection. Oil being sprayed as far back as resonator.
You could have an upper or lower oil pan leak, or your have bad oil cooler return lines o-rings. But the only true way to know is to track the oil leak. I would get several cans of brake cleaner and spray the entire lower engine down to assess where the oil leak is coming from.
But one of the reasons why the PPI didn’t identify the oil leak, is because they didn’t remove the under belly pans from under the car.
just hope it’s not a rear main seal, which would require removing the transmission, as this would be costly.
I don’t know why, but any good shop can identify the source of an oil leak. I had an upper oil pan leak earlier this year, and that wasn’t a cheap fix, the entire front subframe, suspension, steering rack had to be removed, along with the entire oil pan. I have photos in a thread on here.
First identify the leak, determine the cost, then repair.
You could have an upper or lower oil pan leak, or your have bad oil cooler return lines o-rings. But the only true way to know is to track the oil leak. I would get several cans of brake cleaner and spray the entire lower engine down to assess where the oil leak is coming from.
But one of the reasons why the PPI didn’t identify the oil leak, is because they didn’t remove the under belly pans from under the car.
just hope it’s not a rear main seal, which would require removing the transmission, as this would be costly.
I don’t know why, but any good shop can identify the source of an oil leak. I had an upper oil pan leak earlier this year, and that wasn’t a cheap fix, the entire front subframe, suspension, steering rack had to be removed, along with the entire oil pan. I have photos in a thread on here.
First identify the leak, determine the cost, then repair.
Thanks for the reply. My local mechanic sprayed some kind fluid when diagnosing which I'm sure is the cleaning fluid you mentioned. Hopefully they can track the leak with the dye they put in when I head back in after a few hundred miles...Yes I think you're right regarding the engine belly pans. My local mechanic removed them and it had maybe 50-80mL of oil judging from just looking at it. Paid $130 for that PPI in SJC, not sure where it went as they said nothing was wrong with the car.
Read quite a few prior posts here with most people claiming it is a rear main seal leak between the engine block and transmission. As you mentioned it could be the oil cooler return line o-rings also. If it's the rear main seal then either the trans or engine needs to be pulled out. Wish I had known this issue before so I could bargain down the selling price. Well, I guess this is a wake up call to the costs of owning an AMG lol. I'd previously just considered if the headbolts had been replaced to gauge whether I should buy or not [The reason I bought this one because the headbolts had been replaced].
Most new owners of older AMG's probably didn't consider that these were $100,000 vehicles when brand new. And as such still retain the equivalent price when it comes down to repairs.
Just saying, that these things aren't cheap fixes, unless your doing the repairs yourself.
Enough said..... Here is the link to my upper oil pan leak, earlier this year. https://mbworld.org/forums/w211-amg/...mp-my-e63.html
As these cars continue to age, seals becomes dry and brittle and will start to leak. This is just the nature of all things, no matter what brand of vehicle it is.
The big issue is finding out where the leak is coming from first. Then diagnose how to repair the leak second.
I don't understand the dye thing, any competent mechanic can trace the origin of an oil leak, hell I can do that myself.
Everyday you drive the car, your oil is being depleted, are you checking it everyday? The one saving grace, is that the car will tell you when your a quart low on oil.
But oil usually leaks from the valve cover gaskets, oil filter housing, cam adjuster housing, oil cooler return line O-rings, upper and lower oil pan, and rear main seal to name a few.
With the last two being the most expensive. What I would have done, is spray the entire bottom of the engine, tranny and exhaust down with brake cleaner. Then use compressed air to spray off the remaining cleaner.
Lower the car on the lift, have someone get in and start the car, then raise it back up and search for the leak. Easier than using dye.
The beauty about my shop is they allow customers in the bays to look at the work that is being done. I actually assist in my repairs, and turn wrenches along with my tech.
Well, I hope your repair is cheap, as mine wasn't cheap or an easy fix.
Is there not also a "hidden" plug on the front of the engine that has an O-ring that can fail? This one comes to mind because it looked like a PITA to replace that one little O-ring...
Yeah, I had put aside another few grand for the next few years which is how long I plan to keep the car...just didn't realise I'd have to spend money as soon as I bought it when the PPI said it was good to go.
The mechanic I gave it to here in Houston did all you mentioned, minus lowering the car in the lift and running it again. Just told me to come back after a few hundred miles.
Drove the car again today ~50 miles, I mean it drives really well - pulls really hard and no rattles/squeaks. But the amount of oil I saw at the mechanic was worrying. Attached another picture I forgot to add on the original post. Will get some different opinions by different mechanics over the next few weeks. Fingers crossed it aint the little o-ring bbirdwell mentioned. Read the article, indeed looks like quite the intimidating repair for something that small.
My first advice is relax. I know it's not fun to have a problem right after you bought the car, but that's the chances you take with an older car.
You asked "is the engine worth saving", did you run on low oil? The M156 can take 9L of oil, so even if there is a big mess under the car that doesn't mean you damaged anything.
Lastly, if you are going to have a problem an oil leak is an expected and fixable issue. Yes, it may be costly depending on the source of the leak, but it is fixable and you will get back on the road. My last advice is to take your time, and get someone who knows what they are doing. If it is anything other than lower-oil pan leak, it may turn into a bigger job. You want someone experienced that will replace any other item that needs replacing while they are in there.
From the photo you've provided the oil is coming from the engine, possibly upper or lower oil pan. And it has been leaking for a while, for that amount of oil.
The absolute worse thing, you can do right now, is let your car run low on oil. Until, you get your issue fixed, check your oil level daily.
Like desertfrog stated, this isn't the end of the world, these things happen to well maintained cars, and can be fixed.
Most new owners of older AMG's probably didn't consider that these were $100,000 vehicles when brand new. And as such still retain the equivalent price when it comes down to repairs.
Just saying, that these things aren't cheap fixes, unless your doing the repairs yourself.
Enough said..... Here is the link to my upper oil pan leak, earlier this year. https://mbworld.org/forums/w211-amg/...mp-my-e63.html
As these cars continue to age, seals becomes dry and brittle and will start to leak. This is just the nature of all things, no matter what brand of vehicle it is.
The big issue is finding out where the leak is coming from first. Then diagnose how to repair the leak second.
I don't understand the dye thing, any competent mechanic can trace the origin of an oil leak, hell I can do that myself.
Everyday you drive the car, your oil is being depleted, are you checking it everyday? The one saving grace, is that the car will tell you when your a quart low on oil.
But oil usually leaks from the valve cover gaskets, oil filter housing, cam adjuster housing, oil cooler return line O-rings, upper and lower oil pan, and rear main seal to name a few.
With the last two being the most expensive. What I would have done, is spray the entire bottom of the engine, tranny and exhaust down with brake cleaner. Then use compressed air to spray off the remaining cleaner.
Lower the car on the lift, have someone get in and start the car, then raise it back up and search for the leak. Easier than using dye.
The beauty about my shop is they allow customers in the bays to look at the work that is being done. I actually assist in my repairs, and turn wrenches along with my tech.
Well, I hope your repair is cheap, as mine wasn't cheap or an easy fix.
Originally Posted by Yuille36
From the photo you've provided the oil is coming from the engine, possibly upper or lower oil pan. And it has been leaking for a while, for that amount of oil.
The absolute worse thing, you can do right now, is let your car run low on oil. Until, you get your issue fixed, check your oil level daily.
Like desertfrog stated, this isn't the end of the world, these things happen to well maintained cars, and can be fixed.
Thanks, will keep this thread updated on fixing this leak.
Check your power steering fluid. If it is low, fill up, turn the steering wheel all the way to left/right few times, drive and make a few sharp u-turn then check your fluid again. I had a small leak under the engine before, it turned out the PS pressure hole was leaking.
Updated 2: returned to the mechanic after driving 160 miles. They said it's definitely not rear main seal, and said oil is likely coming from higher up in the engine bay. Quoted me $330 to remove the intake manifold to get a better look.
I have attached a YouTube video for anyone interested (
) . I've also attached a photo of the underside plastic, which contains 160 miles of oil leaking. I think the actual amount leaking is more as it'd get blown away by the wind while driving.
EDIT: mechanic also said oil is "coming from out of the oil drain channels"
I was also just thinking, this car had a recall for the fuel tank. If I take it to the dealer and have it replaced, I guess they could also diagnose any other issues? (I don't actually smell any burning fuel, but previous owner said its the original tank, you can take it to the dealer if you smell anything and they'll replace the tank for free).
Last edited by MbBiturboFan; 11-10-2020 at 07:16 PM.
From these photos, it looks like you have either a valve cover gasket leak, or the cam adjuster housing are leaking, and a lower oil pan leak. I would also check your oil lever, to determine just how much oil your leaking out. The absolute worse thing you can do is let this engine run low on oil.
From these photos, it looks like you have either a valve cover gasket leak, or the cam adjuster housing are leaking, and a lower oil pan leak. I would also check your oil lever, to determine just how much oil your leaking out. The absolute worse thing you can do is let this engine run low on oil.
Thanks for the response.
If it was a valve cover gasket leak or cam adjuster leak, wouldn't I be able to see the leak just from looking at the engine bay? It looks clean to me - no leaks when I view the engine bay normally.
And yeah, I was suspecting a lower or upper pan leak. Due to the way the oil kind of stained the engine on its way down, I suspect it could also be the upper pan. For now, I bought some Liqui Moly 5w-40 oil and will top up here and there to maintain correct oil levels.
Either way, this kind of stuff is disheartening after just having bought the car. Had it been before, I could have negotiated the price a bit.
Hmm, I didn't catch that. I had a look at the video again, I don't see any leaking PS hose...Could it be a bad PCV valve? [crank case breather valve] after researching some more, it could be that, not sure. In the service records, the pcv valve isn't mentioned, and it now has nearly 138k miles.
Hmm, I didn't catch that. I had a look at the video again, I don't see any leaking PS hose...Could it be a bad PCV valve? [crank case breather valve] after researching some more, it could be that, not sure. In the service records, the pcv valve isn't mentioned, and it now has nearly 138k miles.
I had my son lock the steering wheel while I was underneath the car, oil sprayed out from that hole. Have you checked the PS fluid?
I had my son lock the steering wheel while I was underneath the car, oil sprayed out from that hole. Have you checked the PS fluid?
Haven't checked the power steering fluid, which hole are you referring to exactly? The image Yulie36 posted was a hose. I just went and had a look from up top, I see no fluid leaking anywhere...
If it was a valve cover gasket leak or cam adjuster leak, wouldn't I be able to see the leak just from looking at the engine bay? It looks clean to me - no leaks when I view the engine bay normally.
And yeah, I was suspecting a lower or upper pan leak. Due to the way the oil kind of stained the engine on its way down, I suspect it could also be the upper pan. For now, I bought some Liqui Moly 5w-40 oil and will top up here and there to maintain correct oil levels.
Either way, this kind of stuff is disheartening after just having bought the car. Had it been before, I could have negotiated the price a bit.
The reason, I say this is because from your video, you can see oil residue right below your headers. So how did the oil get there? From leaky valve cover gaskets.
Not all the leaks will be visible from up top, it could be leaking from the back side. Regardless of location, you have a oil leak on your hands.
Ok, oil leaks typically come from oil filter housing gasket, valve cover gaskets, cam adjuster gasket, front or rear main seal, front engine cover, upper/lower oil pan gasket, oil cooler o-rings.
I'm very knowledgeable when it comes to oil leaks, as I have replaced everything except from front engine cover and front and rear main seal over the last three years.
this is the photo he sent me...they added white paint to identify what is a new oil leak. basically AMG as smart as they are designed an access port that is behind the timing chain cover.
I assume this failed because they used the same o-ring material as the failed o-rings at my oil cooler hard line coming off the block. I had my mechanic change those o-rings last week. they were hard as rocks and brittle as hell. at that time was when he discovered the valve covers were leaking as well as something near the AC compressor. dealer gave me green replacement o-ring for the oil lines after calling the magical Mercedes hotline where they have all the answers. not sure what material they use but I've never dealt with a Japanese built engine where any o-ring ever failed even over 200k miles. only on the coolant side, but never on the oiling side of the engine. I'll have to inspect as they tear down the front of the engine. really a shame, I'm sitting at 121k at the moment...the only thing that could happen next, crossing my fingers would be a head bolt failure. really hope I don't have to deal with that. these ticky tack repairs are putting me farther away from being able to do a head bolt job.
looks like you may have a few leaks. when i had my car serviced, i had a bunch of things changed including resealing of mid oil pan and lower oil pan as well as front timing covers. my lower most oil pan cover seems to be leaking once again. rear main seal looks fine and hasn't been updated to my knowledge on my vehicle.
When I had my upper pan leak, that was a big expensive job. As the whole entire engine sub-frame, steering rack, suspension had to be removed to gain access to the entire upper and lower oil pan.
If it was a valve cover gasket leak or cam adjuster leak, wouldn't I be able to see the leak just from looking at the engine bay? It looks clean to me - no leaks when I view the engine bay normally.
And yeah, I was suspecting a lower or upper pan leak. Due to the way the oil kind of stained the engine on its way down, I suspect it could also be the upper pan. For now, I bought some Liqui Moly 5w-40 oil and will top up here and there to maintain correct oil levels.
Either way, this kind of stuff is disheartening after just having bought the car. Had it been before, I could have negotiated the price a bit.
I can relate.
Bought my E55 last year and have spent thousands fixing it. I wish I would have made a lower offer as well, but I didn't know the previous owner was being dishonest until I got it home.
I just had the gaskets and oil filter housing replaced. Thought the leak was fixed until today when the car told me to add a quart of oil. It isn't leaking on the ground, so I can't tell where the leak is. Ugh...it never ends.
Bought my E55 last year and have spent thousands fixing it. I wish I would have made a lower offer as well, but I didn't know the previous owner was being dishonest until I got it home.
I just had the gaskets and oil filter housing replaced. Thought the leak was fixed until today when the car told me to add a quart of oil. It isn't leaking on the ground, so I can't tell where the leak is. Ugh...it never ends.
I agree. It's very disheartening.
Unfortunately, most oil leaks can’t be detected by looking from the top of the engine. You have to use a lift, and remove the underbelly engine trays to really look for leaks. The trays tend to catch any leaks, so you can’t see any leaks from looking under the car. That why it’s so important to get a PPI, before you buy.
Alright, decided to go to the dealership to get it diagnosed once and for all. After 2/3 mechanics said its the rear main seal, the dealership wanted $64.50 to identify the oil leak. They confirmed that it is the rear main seal that needs replacing, and also pointed out another small leak from the upper oil pan.
The RMS was $1892.44 and upper oil pan leak is $2174.56 at the dealership here in Houston.
Since the RMS is the one spewing out the most oil right now, I'm going to get it fixed at an indy, for which after calling 9 places, the lowest estimate I got was $850. I'll go ahead with that I think, which seems like a fair price considering the transmission needs to be removed to get to the seal. I'm ignoring the upper pan leak right now, which the dealership said to be quite minor and nothing to worry about for now.
One of them also suggested to get the "crankshaft position sensor" replaced as well, as oil around there can short it out. Is this necessary? (He quoted an additional $180 to do that, parts + labour).
10-27-2020, 04:05 PM
