hi guys newbie here. intro myself charlie keeper of jaguar xk 4.2l 57plate . ive small prob and its this .on the odd time that you get to floor the cat i some times get a smell in the cabin wouldnt say its a clutch smell but it could be. but it stinks only lasts for a min or so then goes away. but its only now and then it happens. ive had machanic on test drive with me floorded it no smell. it only happens now and then and its bugging me any advice WELCOME THANKS

 

(For our US cousins, '57 plate' = 2007)

I've never smelt (or heard anyone talking about) burning clutches with an auto box. There are clutches in there, but the whole thing is pretty well sealed. When the front clutch went on my XK8, there was no smell. Maybe you're just burning off accumulated crud in the exhaust, which then gets drawn back into the car because of the suction effect behind it. Next time, look in the rear-view mirror - if there's a cloud behind you, summat's burning off.

But I may be talking out of my ****, so take it with a pinch of salt.

 

I get an exhaust smell in the car from time to time if I give it heavy boot. We have unleaded fuel here, so it doesn't smell that good at all.

 

It's unleaded everywhere these days. What tends to lead to bad exhaust smells is sulphur - the mix of higher-sulphur fuels & catalytic converters creates one of the 'eggy' sulphur gases (can't recall if it's H2S or SO2). Maybe sulphur content is still high in Oz? It was lowered significantly here in the late 90s, I think, which is what saved the Nikasil engines in the 4.0 XK8 - if the engine survived the brief period when it was exposed to high-sulphur fuel, it was OK after that.

 

Yes, I was going to say it smelled like farts, but was too genteel. We have normal unleaded (91 octane), 95 octane, and 98. I think the Jag is recommended to run on 95, I run mine on 98 though I dont know whether it makes any real difference.

 

Recommended octane level is 95 RON "or higher", minimum is 91 RON. But, as I said, it's the sulphur content that causes the stink.