1993 xjs 6 cylinder puffing smoke on startup
 

just bought the car, had been sitting for many years, i'm sure it's the valve stem seals. anyone have any idea, oil treatments, whatever, aside from having to tear off the head. just a little puff on startup if it's been sitting for some time.

I used to replace the stem seals sitting on top of the engine cross legged on blankets and cardboard.

You can do the compressed air or the rope-through-the-sparkplug-hole trick to hold the valves.

The cams and cylinder head bolts must be removed and Jaguar has special tools to temporarily reinstall the bolts to hold the head without the cam caps or reinstall the cam caps temporarily.

You can use some hollow tubes the thickness of the cam caps to use the head bolts.

Jaguar also issued a TSB recommending re-use of the headbolts TWICE (TSB 12-62am) but that is up to your discretion.

Some guys in the shop pulled the head and some did the stem seals on the car.

If oil is seeping from the front-right area (common fault) then the updated head gasket should be installed and the HEAD-OFF method used.

OR you could just ignore it and go on with your life. It won't really hurt anything except some build-up on the valves.

bob gauff