Ok, before all the jokes start, in all seriousness, this does cause my wife and I headaches, so it is something potentially dangerous.

1971 XJ6, exhaust has been replaced, had the new battery replaced because it was defective with charging and filled the garage with the sulfur/rotten egg smell.

There are two smells: one it always has, and second after 20 minutes of driving/running.

The first is the old oil, greasy, exhaust smell.

The second is the first plus a little burning plastic sulfur smell.

The cooling system does not leak, and we are using the pet safe stuff. Oil is Mobil 1 synthetic, couple of drips here and there (typical 70's leaks Lol). Trans fluid was changed to type F.

The smell can be somewhat blocked from the interior by switching from fresh air to re-circulation.

The exhaust tips are factory straights, only using one gas tank, and the bad smell is only after warming up and a minimum of 20 minutes idle/driving time. The car was a barn find that sat for 35 years, brakes are original but put on new in 1980 when parked, parking brake DOES NOT work, and rear gear oil has NOT been changed.

Any assistance is appreciated.
Thanks, Paul
ps a few jokes are ok

 

The controversy between straight pipes and s pipes get batted around a lot in here, im sure someone will chime in on it, basically the theory, ( or so i have read on this and other forums) is that the s tips push exhaust into slipstream of car and away from the floor vents under the trunk, now whether this is true or not is open to interpretation... i dont even know if your car has the trunk vents, or what year the s tips came into being. But needless to say if its giving you both headaches, park it until its figured out. Good luck with it!!

 

The manifolds may be leaking.
If you've just replaced the exhaust the other smell could be exhaust sealant burning/ setting,

 

thanks for the replies!

It was doing this before and after the exhaust replacement. One good thing was after the exhaust replacement, that smell went away.

She does have the trunk vents.

 

Check the manifolds (headers) for leaks.
Check the crankcase breathing system is intact and not leaking.
The fact that it gets better when in recirculating mode leads me to suspect the engine compartment.

 

what he said

check that nothing is touching or leaking onto the exhaust manifold and pipes up front, and that they are tight, when it hot and running. Only takes a drop or two to create fumes boiling off and not be obvious when stopped.

 

Two ideas:


1. There are two vents on the rear valence of my SIII, which may exist on your car. Vulnerable to getting 'squashed". Mine were. Easily fixed by prying them open with an old retired really big flat blade screw driver Didn't even scar the paint!!!


2. There is an open vent in the boot in my car!!! I see it as a part of the cabin vent system. And, I've never checked them,. but there are vent flaps in the rear of the cabin that did have seals. Known as "cow bells". Odd, why not!! But, if those seals have failed, a back draft seems plausible. Fuel fumes in the boot are not unknown!! And/or exhaust from the "'straight" tips???


2. A past lister on another forum addressed this issue with a computer sourced small fan to vent the boot. Connected to the fuel pump as a source of 12v. Whenever the pump runs, the boot is vented. I saved one from a defunct unit. I've noted it is 12v powered.
A future project, amongst so many...


And, happy wife, happy life.... well worth solving it, whatever it takes...


Carl
C

 

Hi Paul,

My car had a similar smell to what you describe when I first got it..I totally covered engine bay in a degreaser solution and water-blasted it clean.. since then no more smell..well not from the engine at least !!

Cheers

 

Again, thank you everyone!

Here is what I have found:
1-Voltage regulator on the Butec alternator was turned high, battery was overcharging, sulfur smell after running.
2-Manifolds are not leaking.
3-the recirculating vents above the trunk lid have the "goat bell" sound when closing doors.
4-the cam covers have very tiny leaks along with the breather at the front of the block between the cams.

So..... I turned the voltage regulator down and so far the sulfur smell is gone.

I am going to check and repair the recirculating vents and other vents and see what happens.
Paul

 

Paul, you might be surprised how little burning oil from leaking cam cover gaskets it takes to smell up the environment in and around a car. (You can ask me how I know.) And it smells Just like old oil slightly too warm.

If it's not too much trouble (how much trouble depends on how annoying the smell is) you could change out the cam cover gaskets and see if that Finally fixes your problem.
(';')

 

Check the rear diff, the output shaft seals are prob leaking on the brake discs, 90w gear oil really stinks. Very common on Jag diffs. Pinion seal prob leaking too, it can be easily replaced but only by a competent mechanic that's familiar with the job, otherwise you'll be replacing the diff!

Btw... I pressure wash the engine bay on all my cars including the XJ6 with no problems whatsoever. Get all the greasy crud off the front of the motor and blast those greasy oil cooler lines, they leak and stink. Lines and cooler have to be replaced, cooler threads strip when removing the lines...

 

RSQ911:


1. Adjustable out put on that alternator. I've not heard of that for decades!!!
slick. Now is the time for the VOM! And better yet for a tap to connect the VOM in the cabin. Read volts in real time under various rpm and load conditions.


2. I can't think of an engine bay in an 'experienced" car that doesn't have some smelly vapors. But, how do they get in to the cabin?


Check the openings in the fire wall.


A. Throttle and cruise control cables.
B. Heater hoses.
C. AC at the Ranco.
D. HVAC vacuum spigots under the battery
E. A big grommeted opening under the battery for the wire harness.


And then the console? Is the big pad still there? Soaked in old oils?


Mine was so grungy that I "dumped" it.


But, as an old gear guy, I'm tolerant of a bit of oily odor. My jaguar seems relatively free from it. My Jeep does have a tinge of it at times???


Carl

 

Check this out Carl...

Volvo Adjustable Voltage Regulators

Older bosch alts are notorious for low output setting, common on bmw's and volvo's. This works a treat!

 

Many thanks. Although, there are no Bosch units in house, who knows about the future.


And, a lot of the information is generic. useful, absolutely.


And, a good start for the morning. I've known that generators needed polarizing at times. But, flashing the field in an alternator is new to me!!!


The table showed a Delco? My lump has a really big one. Plenty of volts as it is.


Not sure what critter my Jeep has??? Built in the days that MOPAR had a working relationship with Mtsubishi, so ?


Carl

 

Again, thanks everyone!

The smell is 100% for sure, the battery.

Apparently the Butec alternator's voltage regulator is over charging at times.

My question is this, does anyone make an updated version of the regulator c31526, or aftermarket? The reproduction ones are running around $200. Or this is the option of going to the GM Delco one wire.

 

If you are going to replace the Alt - try a Delco CS 130 - dirt cheap (I would not pay more than $ 75.00 USD - new ) Check Rock Auto for online availability plus it starts charging at very low RPM.
I buy them (used - in like new condition) at the local Pull a Part for 20 dollars ...pop in a set of brushes, and good to go for a long time...