dawson1331

For the last several months, my 2019 S560, has occasionally given off a very strong gas smell. It happens once or twice a week. The problem was not reproduced at MB Service. I left it there for several days at a time - twice. They could not find anything and eventually wanted their loaners back. In addition to a bad smell, I worry that this could be dangerous. Any ideas are welcomed - no matter how crazy!

Here are two typical scenarios:
1. Car parked in garage, not driven since yesterday noon. Leave the house through the garage vehicle door for a two hour walk at 2pm. No smell. Get back a little before 4pm. Strong smell in garage. Seems to be strongest in engine compartment passenger side but hard to tell. Maybe twice a week since November.

2. DrIve car in morning short distance (less than 1/2 mile). Stop at traffic light or final destination. Twice gas smell strong in car - windows rolled up. Two other times walked around car in parking lot - strong gas smell. If I continue to drive smell goes away. Only noticed this 4 times since November.

More info:
There is no gas on garage floor underneath the car or otherwise.
No other gas sources in garage, except 2017 SLC43. Ruled that out.
Seems to happen most on Thursdays.
Seems to happen most between 3:30pm - 5pm.
Seems to happen most on sunny days where the temperature increases in the afternoon. So not necessarily the absolute temperature but a change in temperature.
Also seems to happen more often on windy days.
Smell lasts an hour or so.
Smells like an ounce or two of gas was spilled. Very strong - no question it is gas.
Not a function of gas tank fuel level. Happens at full tank and 1/2 tank. Originally MB said I over fill the tank when refueling but that has been ruled out.
During pandemic, I refuel about once every 3 or 4 weeks.
I have been keeping a log since March. Date and time, temperature in garage, weather conditions, gas tank level, etc.
Three car attached garage, with two cars and storage space. Garage vehicle door faces west (sunny side).
I am technical but not a mechanic. I do not work on cars.

Thanks,

Bill D.

Streamliner

Please know that I can understand your frustration with this. That said, you need to remove the “Seems to happen most on Thursdays” from your list.

chassis

There is/was a problem on W212 where the fuel pump sealing ring and gasket fails, allowing gas smell. Unfortunately it seems this might also affect W222.

User ​​​​​@39039 has some great YouTube videos on how to repair W212.

If you have EPC you can dig through the part numbers for the fuel pump, sealing ring and gasket and compare between W212, W213, W221 and W222. If there are common part numbers chances are the experience will be similar.

39039

Thanks Chassis recommend. Actully I was tired dealing with dealers, so I have to do it myself, even in the period of warramty. If I were you, I'd find it out by self and let the dealer fix it.

39039

Here are the two video for repair the gas leaking of W212:
Replacing the sealing:

And replacing the cap of the gas tank:

MBNUT1

This member (2012 merc amg) has had fuel smell issues with his as well. Sounds like this is an issue for the S560

https://mbworld.org/forums/s-class-w...erience-5.html

2012 merc amg

Yes, I'm still going through it. Had the car at another dealer yesterday and was waiting while they looked over the car. They were not too happy with me for bringing the car in and wanting to wait for such a big problem but I just felt I needed another dealer to check the car over as I've been told 3x by the other dealer they cannot find anything wrong and all system are functioning as normal on the work order sheets. The dealer that looked over the car yesterday claimed one of the fuel lines was slightly loose and they tightened it and said maybe it would fix the issue. The service writer told me if it does not fix the issue that he was going to need the car for at least a week and they would then try to replicate the issue. What I have learned is that starting on the 222 model there is no longer access to the fuel pump from under the seat as they had issues with the plate that covers over the fuel pump assembly on the older cars leaking and leaking gas or fumes into the passenger compartment not good. More than likely mechanics not installing and sealing the plate properly. But now the only way to access the fuel pump and lines is to remover the fuel tank. What I've found is that all conditions the the dealers try to avoid doing that as much as possible but that is more than likely where your problem and my problem lies. I still have the issue, verified it earlier tonight, I kinda figured it was not fixed sounded too simple. Looks like at this point with my car I may have to get Mercedes involved. This has been going on for 4 months or so since I bought the car used Certified. I can sympathize with what you are going though, I've never any problem like this with all the cars I've owned. My car only has 20K miles on it. 2018 model S560. I guess worse comes to worse I may end up having to get an independent shop to fix the car and I'll send Mercedes the bill. What the service writer told me yesterday is that there are 2 fuel pumps in the fuel tank and the fuel is transferred around in the tank. I think maybe it has something to do with the low pressure lines that go to the low pressure pump which would make sense to me but I don't know for sure.

chassis

Need to call BS on the dealer. Mercedes appears to have a problem. O-ring and locking ring (bayonet coupling) are the same between W212 E350 and W222 S560.

On 2018 W222 S560 the fuel pump, locking ring and o-ring are accessible from inside the vehicle in the normal way, shown in the videos from @39039

See attached.

W222 2018 S560
Locking ring/bayonet coupling: A0014711430
Gasket/O-ring 135.5x6: A0259971845
Feed unit: A2224700094

W212 2016 E350
Locking ring/bayonet coupling: A0014711430
Gasket/O-Ring 135.5x6: A0259971845 (was A0149978945)

2012 merc amg

Wow, the Service guy bold faced lied to me yesterday. He insisted that the fuel tank had to be removed in order to do this repair and that they would need the car for a week at minimum. It's really starting to sound like I'm going to have to find a good independent shop to do this repair. Its become obvious to me at this point that the mercedes dealers at least here in Florida cannot handle this repair. Maybe they just don't have qualified enough personnel to do the job. I may be able to wait until I get back up north and have the dealer I use in Rhode Island handle this repair for me, I know they do have some really good techs in that shop. Florida is just unreal. I use have hot rods here and I became not capable of working on them myself due to disability and found I could not rely on any of the mechanics I used here and finally had to get out of that hobby. Thanks for posting that PDF Chassis, things are becoming very clear to me now. I'll bet even if they could take the time to pop off the right side seat cushion and take off that fuel pump cover they would see the problem, more than likely one of those fuel lines is leaking. Think about all the damage this is doing to the environment too all these car releasing gasoline fumes, thats really bad. It has environmental lawsuit written all over it.

Streamliner

If the one dealer says they will fix it, but need the car for a week, GIVE IT TO THEM! If that does not do the trick, I am strongly saying, once again, IMMEDIATELY contact MBUSA and open a case on this. Leaking gasoline is a problem that could cause huge problems for them. They will jump all over this.

2012 merc amg

I'm very nervous to give the car to the dealer for a week, might get the car back with the carpets all greasy and they may have driven the car a real lot for no good reason. I'm trying to figure out the best way to duplicate the issue right now so they cant say yet again they don't notice anything wrong with the car. I left the car in the garage for about 15 minutes with the key turned to the on position without the engine running hoping that the fuel pump might pressurize and I'd get the gas smell. Nada. It seems like the main time it does this is in the morning when the car is cold and the trunk or door is opened and the fuel pump primes up. It must be also that the secondary transfer pump in the fuel tank comes on and maybe thats where the issue is at. In these cars there is a pump that moves the gas from one side to the other side of the fuel tank. The tanks have some kind of separator down the middle of the tank. Who knows maybe I have a bad fuel tank? It's a really weird issue. Chances are tomorrow morning if I go out the garage and open the trunk I will get a really strong gasoline smell from the back of the car. It comes after opening a door or the trunk and I hear a pump motor running in the fuel tank. I guess the key would be for the dealer to have the car overnight and maybe a few days to duplicate the problem.

chassis

The next time you smell gasoline, go directly to the right rear (passenger side rear) seat area and note the smell. Then go outside the car and into the left rear (driver's side rear) seat area and see if there is a difference in smell. Note time of day, ambient (outdoor) temperature and engine temperature (hot or cold), and vehicle location (garage, driveway, etc.).

Report back.

2012 merc amg

Thats when I really notice it in the morning when the car is in the garage when I pop open the trunk or either of the drivers side doors cant go around to the other side as I back the car in the garage and the passenger side is against the wall. I had to drop something off at a friends house yesterday and he noticed the smell when he was talking to me with the car running. Normally outside I don't notice the gas smell too much. So I guess the car being cold before started would be the main time it does it. That would mean if the dealer could check for it first thing that would be good. The other intermittent problem is the seat massager cuts out and stops working generally after driving the car at least a half hour, another intermittent problem where the dealer could easily say they could not duplicate. I leave Florida back for up north (1450 mile drive) in about a month and am debating on just driving the car back as it is as I have a really good dealer right near me in Rhode Island and by that time the car will be getting closer to oil change time too so I could get everything done at once. Still not sure what I'm going to do. It makes 4 times here in Florida I've tried to get this issue fixed and now two dealers have not been able to find the issue. I cant waste much more time on it around these parts.

dawson1331

Here is the report on the "experiment" from my log:

3/15 Monday 1:45 pm, parked in garage. Medium strong smell. Did not drive S560 today or since yesterday lunch. Around 12:30pm opened S560 rear door to smell back seat as suggested in MB World forum. No smell. Did same to other back door. No smell. Went in and ate lunch. Noticed strong gas smell in garage at 1:45. Smelled back seats - all good - no smell in cabin. Neighbor came over and concurred. Smell from engine compartment - passenger side - strong. Today is cloudy, slight wind. Garage door closed for an hour. Garage temperature 68. Gas tank level at 5/8. I did not expect there to be a smell today. The "weather" did not seem the same as the other days when the smell appeared. But maybe it's not the weather.

*** I am now wondering if opening the car door or the trunk on a parked car will “wake it up” and somehow and cause gas to be pumped. Each time that we go on a walk, I would always open the trunk (that is where I keep my hat). When we come back from the walk 1-1/2 hours later the garage would smell like gas. Happens one to two times a week.

Other log entries:

2/28 Sunday, 10:10am drove to X (1-1/2 mile), strong gas smell in car when stopped. Also outside of car mostly on passenger side front. Half tank.

3/2 Tuesday 10:30 drove to X, strong smell in car at first intersection 1/8 mile until destination (5 miles away). 45 degrees Sunny. One quarter tank.

3/4 Thursday 2:30pm parked in garage. Did not drive today. Full tank of gas. No smell before 2pm. Windy. 72 degrees in garage. Strong smell. Garage door closed. Engine compartment, passenger side, vent in top plastic cover.

3/11 Thursday 4:50pm parked in garage. Strong smell. Did not drive today. Drove 20 miles yesterday at lunch time. No smell before 4:30pm. Windy. Sunny. Very strong smell at 4:50pm. Garage door closed. 74 degrees in garage. Engine compartment, passenger side the strongest. Smell started easy and grew over 20 minutes. Gas tank three quarters full.

3/15 Monday 1:45 pm, see above.


I am taking the car into MB Service Wednesday morning (3rd time). I don't know what is going on but I do have more information. Thanks to everyone who has commented. I will post an update when I get my car back.

DaveW68

For some reason, the voice of Joe Friday came to mind as I was reading this post.

MBNUT1

It sounds like it is not a function of the pump operating or engine running for that matter. Sounds like just the increase in temperature during the day can cause the fuel to expand and find a place to leak out.

chassis

The smell needs to be definitively narrowed down to inside the vehicle, or outside the vehicle.

If the smell is not inside the vehicle, particularly the rear seat area, it's unlikely the fuel pump bayonet ring and o-ring are the issue. Although those part numbers are shared with W212 E-Class where the issue has been reported.

The diagnosis observations noted above point to underhood fuel vapor. Time for more detailed observation of the underhood area.

Do the following tests on a dead cold vehicle (first use of the day), and then after the engine has been started the first time in the day, and report back:

1. From outside the vehicle, note presence of gas smell, or not, without starting the engine.
2. If presence of gas smell outside the vehicle, stand on the left (driver's) side and the right (passenger) side, and note the smell difference.
3. Open the hood and note difference of gas smell on the driver and the passenger side.

If you have affirmatively ruled in the engine compartment as the source of the smell, look closer at the high pressure pumps. There are two pumps, one at the rear of each cylinder head. They might be visible, but if not, try removing the cosmetic engine cover, and use a bright light near the rear of the engine. Note the presence of gas smell at the rear of the engine, on driver or passenger side. There are two main tubes connected to each pump. The supply to the pump from the tank could be leaking, or the lines between the high pressure pumps and the injectors could be leaking.

I haven't noticed this complaint on other M176 vehicles on this site. (E63, GLC63, etc.).

2012 merc amg

Thanks for the info Chassis, you've been a big help trying to determine the source of the fuel vapor smell. At least with my car one thing I have determined is that it seems to produce the very strong gasoline vapor smell when either the trunk or one of the doors is opened when the car is cold and has sat overnight. From the back of the car when I open the trunk when the car is cold I hear a pressure release sound, much like the sound a can of spray paint makes when you push down on the valve, but it's just for a split second then I hear the fuel pump run for a few seconds and turn off, it is at that time I get the very strong Gasoline vapor odor, as if Gasoline was spilled on the floor, you no leakage under the car, it's bone dry. This really leads me to believe it's something to do with one of the tank fuel pumps. From what I've heard I believe there are two fuel pumps in the tank, as there are two compartments in the fuel tank, one pump is a transfer pump that pumps the fuel to the other side of the tank. I really believe it may be the transfer pump and maybe a low pressure fuel line where the problem exists. It never seems to make this fuel odor that I've seen once the car has been driven the rest of the day and when the car is warmed up which makes me feel a little more comfortable about driving the car around knowing there is something going on with fuel vapor smell. Had it looked at by another dealer last Thursday and they said maybe a loose fuel line which they tightened still has the issue though. What I do now knowing that I'm stuck with this problem is I open the door quickly and start the car ASAP and that does seem to help. Fuel pressure must be reduced when the car is running and therefore cuts down on the amount of leakage. The original dealer that had told me in Sarasota that they could not duplicate 3 times is not even returning my phone calls now. I'll wait until the next oil change when I'm back up north and hopefully they will pull the rear seat or drop the tank or do whatever they gotta do. They don't have the time here in Florida to do this kind of thing. Not enough qualified mechanics either, too many people out with signs begging for money and getting it, why work? Kinda pisses me off to tell the truth. I owned a chain a Quick Lubes and was always providing top notch service for my customers for a long time, now I gotta chase everybody down with everything and near impossible to get anything done these days. Just how things are now I guess, not the good old days anymore, long gone.

Donnymac

2112 and Dawson, in all departments you have my sympathies. As well as you have documented the circumstances. I would find one or two car guys to witness the leak event. That might be enough "proof" on your side to get serious response, especially if you have to climb the MB ladder.

i wonder if your cars were built "together"?

Im going to bounce your leak off a local indy and will report back.

chassis

@2012 merc amg You really need to narrow down the location in the vehicle, where you notice the smell. It needs to be pinpointed. Candidates so far:

- underhood: fuel delivery system, e.g. high pressure pump and lines
- vehicle interior: fuel pump-tank bayonet connection
- rear of vehicle: evaporative system

You need to be confident and precise about the location.

2012 merc amg

Thanks guys. It’s not at all in the interior otherwise I’d be really worried. It does seem to come from around the back of the car. Maybe it is a leak in one of the evap lines or something although if it were I should be getting a check engine light for evaporate leak unless somebody with a scanner turned off that code warning. Seen that happen with used cars when someone tried to cover up a problem because they don’t feel like pulling a fuel tank or dealing with the problem. I bought the car certified about 4 months ago. Had this issue since I’ve owned it.

dawson1331

I took my car to MB Service today for the gas smell problem. I have hope!

I talked with the lead tech/shop foreman. I described the problem as outlined in the above posts. I showed him where the strongest gas was. He said he has seen this once before and then he removed the plastic engine cover. (I wish that I had known how easy that was. I probably would have seen something earlier.) There was no liquid gas - since the engine had been running awhile. But he did see where the may have been some liquid residue (on a metal surface) and possibly previous wet spot on a rubber gas hose. He said the previous case was intermittent and depended on things like the temperature (like my problem). He would try to reproduce the leak and take a picture for this forum. A very short rubber hose will be replaced - which is not in stock and will have to be ordered. This is a low pressure gas line. The high pressure lines are all metal. So we will have to wait a couple more days. If this is the problem, I will send pictures. I know where to look now. If it's not the problem, I will also post that.

I also confirmed that when you open the car doors or trunk (in my case), the car will wake up. It thinks you are going somewhere. It will pump gasoline (among other things) - even if you don't go anywhere or don't start the engine. I guess that's a good thing - as long as there are no leaks!

2012 merc amg

Bringing my car in later today, well that's good at least you got somewhere. I don't really have much hope with my car after just talking with the service advisor there. They have not been able to find anything the last 3 times I mentioned it. Seems like as long as the car runs and drives everything is fine. In the meantime I have leave my garage doors open for quite a while to air out the garage. I can only imagine what all these gas vapors are doing to the environment and me. Does not sound hopeful they are gonna do anything with the seat massager not working right either. He said they will only do a reflash of the seat module when there is a update issued by Mercedes so I'll probably just have to live with a broken seat massager too. I guess if nothing gets done this time about both these issues I really need to get mercedes involved at this point.

Interesting though about the low pressure fuel lines, I have heard this can cause issues from the e class forums. I'll mention it today when I drop the car off. Sounds like you're guy really knew what he was talking about and gave a damm, thats always nice.

2012 merc amg

I agree, really seems like the back of the car which would be the Evap system. I don't get the feeling they are doing any technical tests at the dealer, just park the car around the back and then put it up on the lift and look under it for leaks which of course it is not leaking raw fuel. It seems to me something trips and just pisses out fuel vapors, to the point where I need to open both my garage doors to air out the garage as my eyes are watering. The dealer does not seem to have much of an interest in fixing it. The car is there now and I have a loaner. I'm thinking of calling for a MB area Tech rep tomorrow anyone have a good phone contact number? It would be great if he could meet with them there any make some suggestions. The customer should not always have to be the one to make the suggestions which the dealer then discounts. They are so busy, it's like a 3 ring circus. My suggestion would be to trip off the evap self test with the star diagnostic tool and see what happens, is that when the strong vapor smell appears, if so then it's time for the smoke machine to seek out the leak in the evap system, but what do I know.

MBNUT1

What circuit is the low pressure line part of?