slight whiff of gas inside car-should I worry? - PeachParts Mercedes-Benz Forum

the300 · #1 09-07-2007, 09:59 AM

Hi all:

I just bought a great 1992 300 te which was really well maintained. It was a guys wife's car, and he basically did anything to it that was needed. I purchased it 2 weeks ago and drove it about 1000 miles over that time.

He had not really driven it for the 6 months prior, and now I get an occasional whif of gas coming from the vents when on "EC" but not on full climate control. And I noticed a slight gas smell from under the car but localized to the real right passenger door.

I am taking the car next friday to a local Mercedes shop for a general diagnostic to develop a punch list for things I want done, and things that might come up.

Do you think the car is safe to drive a little until then? I live in NYC, and won't have it out much, but do need to drive about 20 minutes north to White plains on Tuesday.

The smell seems to come and go, too.

Nice to meet you all, and thanks for the kind advice.

G-Benz · #2 09-07-2007, 10:09 AM

You should NEVER be smelling any gas odor on these cars...unless you have a blown 500 ci drag motor residing up front!

What you are smelling is a pinhole leak on the rubber fuel line...the fuel pumps reside just in front of the rear passenger tire...you can hear the "hiss" in that location when the car is running. Even a small leak will emit odor, even if the leaking gas evaporates and doesn't seem to leave any trace of gasoline.

New line runs around $70. can be done at home with the proper wrench...the A/N brass tool is optimum, but Vice Grips will work too...

michael cole · #3 09-07-2007, 10:20 AM

make sure your gas cap is fully closed.i had this problem for awhile when i started filling up at a full serve station

LUVMBDiesels · #4 09-07-2007, 10:34 AM

Quote:

Originally Posted by G-Benz

You should NEVER be smelling any gas odor on these cars...unless you have a blown 500 ci drag motor residing up front!

What you are smelling is a pinhole leak on the rubber fuel line...the fuel pumps reside just in front of the rear passenger tire...you can hear the "hiss" in that location when the car is running. Even a small leak will emit odor, even if the leaking gas evaporates and doesn't seem to leave any trace of gasoline.

New line runs around $70. can be done at home with the proper wrench...the A/N brass tool is optimum, but Vice Grips will work too...

I agree... I had the same issue on the BMW. I would have this fixed as soon as possible. I did drive my car with the gas smell, but if I were you , I would not do it. That was dumb of me.

fahrgewehr2 · #5 09-07-2007, 10:53 AM

Check your EHA valve.

It is located on the rear (towards trunk) side of the throttle body. It is a small black box. They leak an the only way to fix is replacement. You can try the O-ring replacement, but I have never heard of that working, and it didn't for me.

picture:

http://catalog.worldpac.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=26B0N9GQI26B0N9PHZ&year=1992&make=MB&model=300-TE-001&category=C&part=E.H.A.+Valve

the300 · #6 09-07-2007, 12:50 PM

Hi--

Thanks for all the help-I don't mind replacing the line myself, if it isn't a difficult repair. As a novice, I need to get under the car, right?

What merchants do you folks like for parts?

E150GT · #7 09-07-2007, 01:16 PM

Quote:

Originally Posted by the300

Hi--

Thanks for all the help-I don't mind replacing the line myself, if it isn't a difficult repair. As a novice, I need to get under the car, right?

What merchants do you folks like for parts?

We like to buy from this great site here

POS · #8 09-07-2007, 02:23 PM

Start with a new gas cap - it's cheap and effective. It's common with the SLs, perhaps it'll work for an Estate.

G-Benz · #9 09-07-2007, 02:33 PM

Quote:

Originally Posted by POS

Start with a new gas cap - it's cheap and effective. It's common with the SLs, perhaps it'll work for an Estate.

Good point. Although for my W124 and former R129 both issues were fuel hoses...on the SL, it was a loose clamp.

Btw, "the300", when you venture underneath the car, there is a black ABS plastic cover protecting the fuel delivery system. You have to remove that first...4 - 3mm allen bolts I think?

the300 · #10 09-07-2007, 03:02 PM

I am grateful for all the help. Thanks guys. I think I'll work backwards. Gas cap (which does show some corrosion) then if the smell, which is intermittent, persists, I'll get the fuel line done. I am taking the car in for a diagnostic next week, so he can do it.

I hope I can be as helpful in the future to you all as you are to me. Thanks!

the300 · #11 09-14-2007, 12:31 PM

Hi guys--

Ok, took the car into the garage for a checkout and they gave me the list of things they would do over time, and one is to replace the fuel lines. If I get the proper directions from here, the proper parts, and just follow the directions, can a newbie who has worked on cars before but doesn't have a lift do it. Or am I crazy?

When it come to gasoline, I don't mind leaving it to the pros, but if it is something I can do, why not.

Thanks

Falsapartenza85 · #12 09-14-2007, 01:40 PM

Let me tell you! I went nuts with a gas smell on my mother's 1996 E320 that would not go away! One day, it was so bad, it filled the entire garage with the foul odor. To my surprise, the answer was very simple. The rubber seal on the gas cap had a split in it and was leaking gas vapor. To my surprise, this never triggered a Check Engine Electronics. Oh well! So i replaced the cap and VOILA! No more gas odor!

And yes, the odor was coming from the right rear passenger area. The reason? As small amounts of gas pushed their way through the cap (from heat expansion) the fuel would drip down the syphen tube by the rear wheel well.

Just remember, because it is a Mercedes Benz, doesn't mean its any more complex than another brand. KISS! =)

bhatt · #13 09-14-2007, 02:41 PM

Check the flexible rubber hose that goes from the fuel tank to the hard metal lines (the lines that run from the back of the car to the engine).

My wife's SL had exactly this same problem, and the hose looked fine to me. I drove the car around for 20 mins, put it back in the garage, and the hose was all wet with gas.

Hose is rubber covered in fabric. The rubber cracks but the fabric holds it together. Paid $50 at the dealer, but I'm sure I could have taken the two metal ends to a hydraulic shop and had them replace the rubber for just a few bucks if I had more time.

Neal

the300 · #14 09-14-2007, 02:55 PM

Thanks I'll do that! I am going to get under the car tomorrow. Phil in the parts link has been very helpful, too.