battery venting??
 

Hey guys.. how can I tell if my battery is venting? I have a weird smell that almost makes me want to throw up anytime I get near the car when it is running... any help would highly be appreciated. I just started being a Mercedes fan last year. I have a 1987 560SEL, my wife drives a 1989 300SE, and we just bought our sixteen year old son a 1988 300E.

battery venting??
 

help!!! how can I tell if the horrible smell that I am getting from my 560SEL is from the battery venting or some other problem. If it is the battery, how do I solve the "smelly" problem?

Is the battery leaking acid?

I'm guessing the smell is in the interior of the car. My stab in the dark is leaking evaporator and smell is the oil in the system that has leaked into the evaporator box.

sure its not exhaust?

still looking...
 

I had the exhaust system checked out by three different shops and all of them said the exhaust system was perfect. Ron, how do I go about checking the evaperator? Where is it and how do I fix it if it has oil leaking into it? I know I sound kinda stupid... but... I am. Your help is greatly appreciated.

The worst smell I ever encountered on a car was when coolant was blowing past a bad head gasket and getting burned/vaporised and blown out the back.

That stench could have gagged a maggot.

Sure it's not that?

First of all, what is the odor? Overcharging batteries have a sulfur/rotten egg smell. Coolant has a maple syrup smell.

It almost smells like exhaust or oil burning or something, thats why I had the exhaust system checked. Could it possibly be that exhaust is coming in through the trunk area? I'm curious about the leaking evaporater theory. How do I go about trouble shooting that? The smell is on the inside of the car, and almost gets me high when I try to drive it. At this point, any suggestions are welcome ones. I bought the car and have had nothing but problems with it, but little by little I've been able to solve most of it's many quirks. I will not let it beat me!! I will not, I will not!!!

I had a similar problem with my M103 and the cause was a leaky valve cover gasket.

It was leaking down behind the motor, and by cylinder 6 and getting all over the exhaust manifold. The result was a noxious plume of fumes that would get sucked into the car every time I had the vents on.

Feel around behind your motor, there's a semi-circle cutout in the back where the valve cover meets the head. Feel underneath the semi-circle. If there is fresh oil there, replace the valve cover gasket.

Does the smell appear immediately or only after the car is warmed up? Does it disappear as you are driving and re-appear at stop lights? Are you running the vents at all?

I wondered...
 

I'll bet youre right about the valve cover gasket... Yes it seems to be at it's worst when I have the vents on. I was going to get around to the valve cover gaskets, I guess that now is as good a time as any. Thanks for your help!!!
JD

not coolant
 

Definately not a maple sugary smell. Very noxious

I think you found your problem.

Btw, I DID have a battery venting problem on my W124 years ago, and the smell was sulphuric acid vapor...VERY toxic AND dangerous, especially the propensity for the battery to explode at some point!!!

Turned out, the voltage regulator had failed, allowing the alternator to overcharge the battery. I put a test lead on it later and found it to be 17.5 volts!!! :eek:

A clogged CAT has a similar smell

Thanks guys!!! As soon as I find the vacuum leak, I plan on replacing the valve cover gaskets, then a brake job. Maybe I can finally see the light at the end of the tunnel, I just hope its not another train!!!

could your culprit be cheap gas? maybe your getting a sulfer smell from bad gas???