My '91 XJ has been diagnosed with the dreaded 'cracked header'. Lately, my XJ makes some rather nasty smell.. I just passed it off as the leaking header. I have gotten no engine codes or anything, just that smell. Would a cracked header cause a sour smell?

 

Not being able to smell it myself I couldnt tell you. But if the crack is large enough, and it hass a good route into the cab you could be smelling unburnt fuel or just regular untreated exhaust fumes. However I have a crack in the collector of my 97 and I cant smell anything.

 

sour smell is more than likely the cat. I would just cut it off, hollow it out and throw it back under there, or buy a high flow cat.

 

^thats not exaclty legal and frowned upon, you will make us jeepers look bad, but it works great on older XJ's

 

I think there may have been a recall and cat converter replacement for that year XJ. Does it smell like rotten eggs?

 

I dont smell it in the cabin except when my windows are down. And when I park, turn off the key and get out, I smell it. Plus, when its stationary and running, the exhaust smells kinda like rotten eggs when some unburned gas on them. Not truly excrutiating, but it's there.