rotton egg smell

tomt · 10-12-2002, 05:06 PM

I've noticed a slightly sweet smell in my car now and then (sort of like that bad heater core smell in a water cooled car), but today it turned into a full fledged rotton egg smell. STRONG!

It doesn't seem to come from anywhere in particular, but rather seems to be everywhere. It is stronger in the cab and boot.

I thought it might be a cat going bad, but it doesn't really smell at all in the exhaust or engine compartment.

There are no leaks, and I'll full up on all fluids (not sure on Freon actually, the AC sort of works, but that's pretty standard).

This may not be related, but while searching around for the source today, I found my battery was quite hot, and even had a bit of a burning smell... although not the rotton egg smell. I'm guessing that these are not related and that the battery is in need of replacement. I'm not sure how old it is.

Any idea? Thanks.
Rgds,
TT

Face · 10-12-2002, 06:02 PM

I'd bet it was the battery being overcharged or in need of replacement. There isn't any fluid leaking out is there!?

pwd72s · 06:12 PM

I'm still betting on the cat...short drives, not getting hot enough to control the sulphur...but, just a guess. You might try changing brands of fuel, go for a long drive to get everything hot, see what happens. That's not to discount that you may have a charging system problem...easily checked with a multimeter...year of your 911?

mike f · 10-12-2002, 06:23 PM

I had the exact same thing happen. Check out the voltage regulator. It is probably overcharging the battery. Do it soon before you cook the battery beyond repair(not to mention the possibility of destroyng relays, etc.).

pwd72s · 10-12-2002, 06:26 PM

I agree with that...1st, check out the charging system...it's relatively easy to do.

BlueMax · 10-12-2002, 06:35 PM

I also had these same symptoms. It was a bad voltage regulator overcharging the battery. This eventually boiled the battery. The smell comes from the sulfuric acid (battery electrolyte) boiling.
Couple weeks ago a friends battery actually blew its top off (nasty mess).

autobonrun · autobonrun's Garage

The rotten egg smell is typical of any sulfur based material. In oil refineries it is Hydrogen Sulfide; in your car it would be the Sulfuric Acid in the battery. As stated by the other guys, check for a bad voltage regulator. Also check the level in the battery and add water as needed since some probably evaporated.

tomt · 10-12-2002, 07:57 PM

The batterly just took 8 cups of water! Yikes.

The meter read 13.6 VDC... is that too much over 12?

Obviously I didn't think it was the battery, so I maybe left out some important details (hey, just like on car talk

)...

About 6 weeks ago my stereo want wacky and drained the battery completely dead. I removed the battery and trickle charged it over night, and it didn't hold the charge. I gave it a full charge for a few hours and then it held... I don't rememver what the voltage was, but maybe I overcharged it?

I topped up the water level before putting it back in, and I think I remember it taking 2-3 cups.

Also, the little month bubbles aren't punched on the battery, but I looked closer and there is some printing on the lable indicating that the battery was made/installed in 93. It's a 60 month battery, but I'd say it has served its useful life.

How do I check the regulator?

Thanks much guys. Again, this board is awesome.
Rgds,
TT

------
85 carrera targa

cstreit · cstreit's Garage

If your battery was dry, it is probably boiling and would give off a rotten egg smell. Boiling typically occurs during overcharging, often due to failing voltage regulators...

Being a Ducati owner, I'm quite familiar with this syndrom, all early ducati water cooled bikes had this problem.

Bo · Bo's Garage

I'm having the same problem with my 86':

Shot my old battery due to low water level and boiling.
Installed a new battery last week. Water-level is ok, I'm getting a charge of between 13.2 - 13.9V and the battery *still* smells when I take long drives (say, from 45 min and up).
It doesn't get hot however (just luke-warm).

The battery is just a 60Ah and I know this is too "small" really, could this be the problem?

tomt · 08-26-2003, 06:50 PM

The end of the story for me was a bad alternator... this cured both my hunting idle and battery problems -- overcharging!

cary · 08-26-2003, 08:06 PM

Get that trunk cleaned out with water and baking soda. Over and over again. The battery acid went somewhere ?????????? You'll thank me later.

B.Lane · 08-26-2003, 10:50 PM

cat