Petrol Fume/Smell in W126 Cabin

[ymsin]

I have this little problem which I am quite unsure of.

Whenever the 300se gets stuck in a BAD jam which hardly moves for more than 10 minutes or so, I am able to detect a whiff of petrol-fumes smell seeping into the cabin.

Though not frequent that I get jammed so often, I have had this checked by the a/c expert thinking there could be a leak somewhere, and also by the MB tech. who dismantled the air-filter component to check the fuelage. I even got the rear checked to be sure the boot passage is secured. Checked also the entire exhaust line which was excellent.

Anyone with any other possibilities or experience?

[JCE]

Y. M. Sin:

If you have checked everything on your car and it is all in order, and the problem only occurs in traffic, it may not be from your car. Atmospheric researchers have determined that if a car is stuck in traffic for more than 5 minutes, even with the air conditioner on recirculate the air inside the cabin will become much more polluted than the outside air. It seems that pollutants and fumes seep into the car past the foam AC seals and rubber door and window seals, and concentrate inside the car.

You could test for this by taking the car into the country or the top level of a parking structure away from other cars, and simulate a "1 car traffic jam". If there is no odor when away from traffic, you may have found the problem. If this is it, let me know, as I have been investigating adaptation of a hospital HEPA and activated charcoal unit for use in the car when the air is on recirculate, and would be happy to send you the plans. Good luck on the problem!

(By the way, I saw on ChannelNewsAsia that Minister Lee Kuan Yew and the mercurial Gus Dur seem to be on cordial terms again, at least until next time!)



[Edited by JCE on 02-18-2001 at 12:21 AM]

[ymsin]

John - thanks for your suggestion. Did as suggested and found no problems. However, shall anxiously wait for your product as am all for clean air.

Ps. Its heart warming to hear of SM Lee and GusDur on cordial terms isnt it?

[JCE]

Y. M. Sin:
I emailed you a description of the air cleaner system I am looking at adapting. If it doesn't get through (Electrical shortages in California have been playing havoc with our ISP/internet service) I have provided a link to the company below.

The device I am thinking about using for traffic situations is an Austin Air Jr. Air cleaner - http://www.austinair.com . I checked with the factory, and they said it should run fine off a power inverter, and those are only $30-40 for a 150 watt 12V to 120V model.

The whole system would be rather like installing a stereo amp and subwoofer.

I have used these in my home for several years, and they are extremely good at removing dust, odors, and vapors.

[JoeB]

The problem you describe is a common one for the W126 series, including my 420 SEL. A much cheaper and quicker solution is to buy a new gas cap. Worked for me; has worked for many others.

JoeB

[JCE]

A new gas cap is cheap and couldn't hurt. However, if there is no gas smell in the car while idling for 10 minutes in a parking structure surrounded by parked cars, and the odor is only there when idling in traffic jams near other idling cars, then he probably isn't smelling gasoline from his car, IMHO.

[JoeB]

good point. I was basing my reply on the smell of gas fumes (as opposed to exhaust fumes).

JoeB

[ymsin]

JoeB - I am very delighted to share a common experience with our beloved W126 - but do tell me more of your experience and how changing a gas cap helped solve the problem (I am quite loathe to address this as a "problem" coz I believe its a minor dis-customisation - as I would like to think that owning a MB is acquiring part of a auto-history and thus there shouldnt in theory be any problems).

Was your gas cap really worn out? I don't think mine is.

[Bruce B]

I too am experiencing gas fumes inside my Benz but only if the sunroof is opened (either flipped up or slid back). It is more noticeable after making a left turn or sharp left curve when the tank is half full or more. I've been under the hood, checked the fuel pump/filter area under the boot (trunk), and it has a good gas cap seal. Any more places to look anyone?? I LOVE riding with "the top down" but can't for very long due to this.

[Larry Delor]

I had also experience unburned gasoline fumes in the car on occasion. Turns out that it was a slightly leaking EHA.

Check it out... that could be it.

-Larry

[Bruce B]

I have checked fuel pump and filter behind rear wheel, no leaks. I don't see any fuel dripping or puddled under car after sitting overnight. Where is the EHA located, no detectable gas smell under hood but worth a check even though car runs great w/no driveability problems other than odor when sunroof is opened.

[Larry Delor]

Bruce,

The EHA is located under the airfilter housing on the drivers side. It is a little black plastic rectangular shaped piece, with a two wired plug that is on the firewall side. I was usually able to smell it after I shut off the engine and got out of the car. (Sometimes while driving slow too) There was no evidence of a leak under the car. Once I opened the hood, and located it, I put my fingers under it, and they got wet, and smelled of gasoline. I might have been able to get away with just buying new o-rings for it, but at the time had no idea that those were available by themselves. At least this way, by replacing the whole thing, I was sure not to have it drip onto the manifold again.

-Larry

[G-Benz]

The answers so far regarding exhaust fumes while in traffic has merit.

Gas fumes on the other hand require further investigation...it will only get worse!

I have had two experiences with this...the SL had a tremendously bad gas smell at one time (especally with the top down), but it was easily detected as gas trickled out from the bottom of the car. Replaced a bad fuel hose clamp and everything was fine.

Just in the past month, the same occurred with the 300E. But could not detect a leak and nothing dripped when I started the car and inspected the fuel pump area. So I cleaned everything up and tested a few days later. This time, I saw a very small damp area on one of the fuel hoses. So I replaced it and now the fumes are gone.

It's amazing how little gas it takes to announce itself!