When I had my upper and lower tensioners + chain replaced last year, one of the mechanics torqued on one of the front pulleys too hard and it's broken the seal. Now my car leaks 1 quart of oil every 620 miles. Does anyone have a parts diagram of the front so that when I ID the specific pully I can order a replacement? Do I need to remove the entire front end when I do this?

 

I just replaced the timing chains & tensioners in my 98 XJR this winter, and I'm trying to remember which pulley bolts through the timing cover and into the engine block. It must be the alternator belt idler pulley. Are you saying that the timing cover is cracked behind that pulley?

It is possible that the mechanic didn't install one or more of the O rings inside the timing cover, where the pulley bracket bolts pass through and into the block. If the O rings are missing, it could leak some oil, although the leak you describe seems excessive for this. I think it's more likely that the timing cover gasket got misaligned during installation, and is not sealing against the block, allowing oil to run out.

How sure are you that it's not leaking past the harmonic balancer seal? Perhaps the mechanic forgot to remove the plastic seal liner before he installed the timing cover, which means the seal will not fit correctly around the balancer. The plastic would be chewed up by now, likely damaging the seal.

If any of these things are the problem, then yes, you will have to take the timing cover off to fix it. In any case, replacing any of the pulleys will not fix the problem, unless I'm missing something here.

 

Aquifer, if you check out his profile, his vehicle is a 99’ XJ8. Those o rings you’re speaking of is for the supercharged engine only.

 

Indeed. I kinda thought so, but my car wasn’t handy for me to check. I’m sure there isn’t any way an over tightened pulley could be causing the leak, especially since the XJ8 would not have the pulley I mentioned.

OP, I think you need to keep looking for the leak! Timing cover seal or crank seal are the only things I can think of that would let oil out of the front of the engine, or maybe a cam cover, but you’d notice that I would think.

 

On my 2000, there's a thin o-ring that goes between the crankshaft and the crankshaft pulley. Its separate from the much larger front main lip seal that goes between the pulley and the timing cover. It's pretty common to forget or miss replacing that thin o-ring. You'd have to know it was there or you'd never see it. I think earlier models had a different front pulley, but don't know when it changed to the collet design. The idler and tensioner pulleys don't attach to anything that would leak. So more likely either missed that o-ring or didn't install the front main lip seal properly (its got to be set in perfectly square or it will leak).