Weird problem: Sulphur smell from heater

[spressomon]

Ok...this is just bizarre. Ever since completing the 90k work I get a rather obnoxious sulphur smell inside the cabin when the heater is on. I get wafts when I stand in front of the engine bay when the hood is up and the rig is hot and idling; but most intense in the cabin. And there is no scent of sulphur in the cabin when the heater is off or the A/C is on. And the exhaust smells normal...no sulphur smell at all. Oh yeah...on a 5-hour highway roundtrip this weekend I need to use the heater (it snowed!)...and the sulphur smell was obnoxious as heck as long, once again, the heater was on. But today when coming home (up and over Donner Pass) it was snowing...so I had to run the heater...and it was sulphur obnoxious again...until I got on the downhill side of Donner Pass and the smell vanished (even with the heater on!).

The only thing I can imagine is one or both of the batteries (Exide Orbitals) are venting for some reason (sulpheric acid) after the engine gets hot and it's being carried into the cabin...but why just when the heater is on?

 

[SWUtah]

What did you have for dinner?

 

[spressomon]

I knew this thread was going to be risky

 

[Greg B]

What did you have for dinner?

Fish, scrambled eggs, milk, and beer.

I never combine any three of these items. Any two items, no problems. Combine three of them and the sulphur smell is horrible!

Sorry Spresso, I got nothing on this one.

 

[e9999]

dead critter?

 

[Dandon]

Ok...this is just bizarre. Ever since completing the 90k work I get a rather obnoxious sulphur smell inside the cabin when the heater is on. I get wafts when I stand in front of the engine bay when the hood is up and the rig is hot and idling; but most intense in the cabin. And there is no scent of sulphur in the cabin when the heater is off or the A/C is on. And the exhaust smells normal...no sulphur smell at all. Oh yeah...on a 5-hour highway roundtrip this weekend I need to use the heater (it snowed!)...and the sulphur smell was obnoxious as heck as long, once again, the heater was on. But today when coming home (up and over Donner Pass) it was snowing...so I had to run the heater...and it was sulphur obnoxious again...until I got on the downhill side of Donner Pass and the smell vanished (even with the heater on!).

The only thing I can imagine is one or both of the batteries (Exide Orbitals) are venting for some reason (sulpheric acid) after the engine gets hot and it's being carried into the cabin...but why just when the heater is on?

Sulphuric acid reacts with metals, forming a salt which contains the sulphur (metal sulphate) and hydrogen gas, both of which are odorless. So I don't think the smell can come from the battery. A well-known source of sulphur dioxide (SO2) smell (like rotten eggs) in modern gasoline engines is the catalytic converter when cold, but I don't see how that can be related to your problem.
I wouldn't discard e10^4-1 's suggestion of some dead organic matter inside there.

 

[Dandon]

A well-known source of sulphur dioxide (SO2) smell (like rotten eggs).

Sorry I meant hydrogen sulfide (H2S).

 

[rusty_tlc]

Demons have possesed your heater.
Call a priest.

 

[NMuzj100]

Gear oil spill or diff vent tube splatter ?

Cooked and rotting birds nest with eggs?

 

[AATLAS1X]

Cabin filter?

 

[rusty_tlc]

....But today when coming home (up and over Donner Pass) it was snowing...so I had to run the heater...and it was sulphur obnoxious again...until I got on the downhill side of Donner Pass and the smell vanished (even with the heater on!).

....

I was thinking about this last night and it occurred to me that the smell either went away all together (Has it come back since?) or it goes away when the vehicle is running in compression rather than under a load. So could it be related to the emmissions control system?

There is still the possiabilty that your 100 is possessed.
I have this spycam pic of the inside of your heater radiator which supports that theory.

 

[spressomon]

I was thinking about this last night and it occurred to me that the smell either went away all together (Has it come back since?) or it goes away when the vehicle is running in compression rather than under a load. So could it be related to the emmissions control system?

There is still the possiabilty that your 100 is possessed.
I have this spycam pic of the inside of your heater radiator which supports that theory.

Fungai...YOU are the fungai . I was thinking about EGR too...maybe time to look at it tonight. With upper 70's and 80's forecasted for our Nevada Ghost/Mining Town tour I might be able to breathe a little easier on the explore .

 

[spressomon]

Ok...drove the rig yesterday (no heat, with heat, with A/C) and the sulphur smell was gone. However the second/aux battery (Orbital Deep Cycle) was down to 6.98V! After pulling the battery and putting it on a charger for 12+ hours I could only get the battery to 7.04V. And the battery had a mild sulphur smell to it. So...since I can't locate any other source for the sulphur smell I am assuming the battery had one or more cells short out and caused out-gassing? FYI: This is the second Orbital Deep Cycle in two years...same experience both times. When they're out of warranty I think I'll go back to a non-deep cycle type battery for my aux power battery.

 

[whays]

I once had a nasty egg smell while driving my beater pickup truck. It ended up that the voltage reg was bad and my battery was overcharging. Overcharging to the tune of 16+ volts. After a new Regualtor and bettery the problem was gone.

Later.

 

[uHu]

After all a happy ending.

Let the cruising begin !