I took off my cam cover and noticed something strange, the spark plugs were submerged in oil! I was wondering if this could be the cause of my oil burning? If so, would switching out the cam cover spark plug gaskets fix it?

 

I don't think it would cause oil burning but by the sound of it the rubbers are leaking into the spark plug recesses - easy fix though, just change them when you fit the new cam cover gasket.

Larry

 

I remember replacing valve stem seals on dozens of 1994 XJ6 AJ16 engines back in the late 1990s. The engine would 'puff' smoke on startup and many car warranty company policies would cover the stem seal replacement. This could contribute to your oil burning.

You might also consider using 15W40 or 20W50 oil to slow the oil consumption if you are not already doing so.

bob gauff

 

Hi jaguarguy13,

Are you just losing oil somewhere, or are you certain it is burning in the engine?

As Larry mentions, replacing the spark plug O-seals is a simple fix when replacing the cam cover gasket. Replacing the exhaust valve stem seals as Bob mentions means the cylinder head must be removed - a much bigger job. I agree with Bob's suggestion to run higher-viscosity oil. In our '93, I run 20W-50 most of the year and 10W-40 in the winter to make cold starting easier. I've tried 5W-40 but the car seems to lose it at a faster rate, both by leaks and making its way past the valve stem seals and probably the piston rings too.

Cheers,

Don

 

The valve stem seals can be replaced with the head in situ but most people opt to remove the head.

I used to replace the stem seals (all 24) sitting cross-legged on top of the engine with padding and cardboard under me. I weigh around 140 lbs. so I never broke/crushed anything.
You need to have a way to keep the valves closed either with compressed air or feeding rope into the cylinder etc.
Then you will need to re-install the bolts with spacers to simulate the cam caps once a cam is removed for access to keep the head clamped.

Then a valve spring compressor will used to remove/replace the 'keepers' for the spring 'hats'. I use a VW spring tool modified to hook into the cast webbing in the top of the head.

It is probably cheaper to just buy oil and add when the level gets low.
You can but a lot of oil for the time/money spent on valve stem seals.

bob gauff

 

Thanks all for the help! Does anyone have any advice on replacing the stem seals? I already have the cam cover off (basic enough), now i'm not quite sure where to go next for fear of damaging parts. I've done an engine restore on a '69 Mustang so I have some experience with engines.

 

How much oil are you using/losing?

If it's just the puff of smoke on startup, I'd just let it be ...if you're using a quart a week or something like that then maybe it's time to either find the leak or find out where it's going?

Larry

 

IMHO its a cost vs value and you need to determine that for yourself. How much time and effort to save a $10-12 between oil changes every 5000 miles.

I work on cars for a living and havent tackled this job either. Because in my mind its just not worth it. It burns a couple of qts between oil changes and I live with it.

The 4.0L vs any OHV v8 is a world of difference in complexity. You could probably pull the motor on the old Mustang in less time to pull the intake on the Jag. If you could handle a rebuild on the Mustang you could do the valves on your XJ. While it all comes apart one bolt at a time, some bolts are just harder to get at.

I did fix the cam cover and plug seals as they hardened up, filled the plug holes and in general made a mess and then started leaking on to the exhaust and causing a stink at idle. Because it was worth it but a little smoke on start up not so much.