Foul exhaust like smell from rear of XKR (not the exhaust) - RESOLVED
 

We have owned our 2002 XKR 4.2 for only 6 months and we are still working out what everything is and how it works. It has been many years since I last worked on my own cars (such as rebuilding the engine in a 1956 Wolseley 4/44) so I am not quite up to speed with everything. Please be gentle!


We did a 400km round trip today and on the outward trip we noticed a foul sulphurous exhaust like smell when we opened the windows, even at speed. On arrival at our destination we noticed the smell was also strong in the boot (trunk). When we got back home the smell was so strong we had to vent the garage to try and get rid of it. On crawling under the back of the car I noticed that there was steam issuing and water dripping from a flexible tube just behind the rear right hand wheel and inside of the right hand exhaust pipe and this appears to be where the smell is coming from. The pipe is in the middle of the photo attached below. Other than this smell the car is going beautifully. Any ideas what the issue is and how I can fix it? Any help would be much appreciated.


https://www.jaguarforums.com/forum/d...o6UUD1zQB//9k=

Sorry, couldn't get the picture to come up.
Wonder if the smell may be a leak from something that is going onto the exhaust.
I can't tell if you have the convertible, but the rams have been known to leak and stink like you know what, but the rear axle grease is a real eye burner when heated up.


Wayne

The picture did not post correctly, but it sounds as if you could be describing the battery vent. Remove the right hand floor panel in the trunk (boot) and see if the flexible line from the battery into the floor is the same one you are describing.

If it is, be careful, because the wetness is sulphuric acid and your battery is boiling over. You should check that your voltage across the battery is no more that about 14.5 volts with the car running. If it is, your voltage regulator in the alternator has failed and the high voltage is boiling the battery over. If the voltage is OK, your battery just may be defective.

The picture want open but it sounds as though you have located the battery vent tube. You can verify by having someone push and pull gently on the tube from the trunk and watch it move.
The tube may be damaged if you are getting the smells in the trunk.

The larger problem is why is the battery boiling. You need to check the voltage with the engine running to see what the alternator charge rate is.
I think it should be max at about 14.5 volts right after start up and hold around 13.6 while running.

If the alternator is good you need to replace the battery. Be sure to reinstall the vent tube. The battery if correct for the vehicle will come with a new tube and fittings.

Thanks for the pointers fellas, it is definitely the battery boiling. The voltmeter in the car does not register over 13 volts when running so I am thinking that the issue is the battery is on the way out. Is this a safe bet or do I really need to put a meter on the alternator?

You can only trust the gauge to show you alternator is charging. The most accurate is taking a reading while running across the battery.

Thanks Vern, I'll do as you suggest and let you know the outcome.

I have checked the voltage at the battery terminals and have 12.67V when engine off and cold, 14.3V at hot idle, remains at 14.3V when revved to 3000rpm and 14.26 at idle with the lights on. The workshop manual suggests the voltage at the battery on a hot start should be between 13.5 and 14.3V. The battery is rated at 90AH and up to 14.8V. I noticed the battery appeared to be warm to touch but not hot after running the engine up to temp and doing these tests. Would you agree that the alternator is not the issue? Perhaps a fault with the battery? Out of curiosity, if the battery is thought to be at fault, what would cause this?

Your readings would make me think the alternator is OK. Time for a new battery.
I have no idea why it has gone bad.

I believe that the most usual cause of a battery boiling is overzealous charging, or possibly dud cell(s), although I tend to agree with Vern that the voltages you are recording don't indicate the former. Strange that you're not experiencing other issues such as reluctant starting that manifest with failing batteries.

Either way, the gassing is a potential fire hazard (hence the vent) and needs to be addressed quickly.

Load test first, as its a low/no cost step. If it fails, obviously renew the battery. As a practising paranoid, I'd also want to know how much the alternator was putting out to be on the safe side. - Whatever happened to the good ole' ammeter?

Difficult to say what why the battery may be dud - perhaps the car stood at some time in the past and it went flat and sulphated, or it may just be old - you may have a date stamp on the ground terminal that shows the week and year of manufacture. Five years or so and it's on borrowed time...

HTH,
Mike


PS: A bit late in the day, but I've recovered your picture:

An belated and final update on this issue. I finally got around to replacing the battery a couple of weeks back and today has been my first decent trip with the new battery. After nearly 4 hours of varied driving the acid smell has gone. The new battery is behaving itself. It looks like the problem has been solved. Out of curiosity I put the meter on the old battery yesterday and the voltage had dropped back to 10.8V, even though it was fully charged when I took it out, so it looks like it was on the way out. Thanks to all for your help with this. I would be interested to hear any theories as to what caused the old battery to overcharge - a short perhaps?

how old was the old battery? There should be a date code on it but most batteries are good for 3 -5 years.

I know that these batteries are supposed to be maintenance free but in my experience I find that over time the liquid evaporates and eventually the lead plates are exposed. This can cause premature failure and could cause the boiling in a good battery with a good alternator. I would pry the caps off the top and see if you can see the plates in any of the cells. You can top off the liquid with distilled water. When I bought my latest, I had to add 10 oz. to bring the level up to spec.

I had to do the same as Rick when I bought mine. It took about 8 oz. of water.

That's why I only use AGMs now. I had a battery overheat and crack and the acid ate through the plastic side skirt on a Honda I had in high school. I just didn't like the idea of liquid filled batteries being in an interior compartment, especially with the amount of modules around the battery in the Jaguar. I'll do the same for the Lincoln at some point.

I have only owned the car since April so I don't know when the battery was installed and there is no date stamp anywhere on it. It was made in the Philippines and has a stick on label with the name of the supplier, no manufacturer name so I am guessing it was a cheapo. Anyway, the new one is behaving and the car is driving well so I'm happy.

glad to hear all is working well with the new battery. I've changed the title to reflect this issue is resolved

Does your car sit for long periods of time? I had a 2005 XKR that I stored every winter and used a battery maintainer while being stored. The original battery has lasted for over 10 years now.

Hi Bman, we only use the Jag and the MX5 occasionally. They don't get laid up as we don't get really bad winters here on the NW coast of Tassie, very rare to get snow and ice so we do get some use during fine weather in the Winter. They are really an indulgence for a boy racer and his wife who couldn't afford a fast car when they were younger! However, we do keep the batteries topped up with trickle chargers when not in use for a week or more. The chargers effectively hibernate when the battery is fully charged.
The battery that went tits up was overcharging on trips rather than on trickle charge. I couldn't find out how old the battery was but I know it was a cheapo. I checked the voltage a few weeks after swapping it for a new one and it had dropped back from near fully charged to about 7v. Also noted the sides bulging. No problems since swapping for a new quality battery.