Hello,

I've recently started tracking the oil consumption of my '92 Sovereign and after topping up today with about .6qt after 580 miles, I'm wondering where I stand.

The only oil burning I notice is immediately after startup, lasting approximately 45 seconds until the exhaust is completely clear. I've never noticed any oil burning while driving after that point. My engine is (thankfully!) bone dry with no external oil leaks on the block. I do, however, have some oil collecting in the spark plug wells (even after replacing the o-seals, half moons and valve cover gasket with OE Jaguar parts...)

I'm using Castrol GTX High Mileage 10W-40.

Is this normal consumption for an AJ6? IIRC, my engine doesn't have guide seals on the exhaust valves, correct? What would a rough estimate be to pull the head, have them installed, and reinstall the head?

I'll keep tracking the numbers but I have a feeling the biggest variable is how often the car is started from cold. Frequent short trips would give me more consumption, right?

Thanks,
Nick

 

45 secs does sound like a lot, I only get the occasional puff which maybe lasts one second or so - however mine does have seals (but of course they are probably hardened and shot at 210,000 kms) ...

If you have no leaks as you say, sounds like the oil is being consumed by that 45 second push of blue. Fitting seals should fix it for a while, but eventually it will behave like all of them with that distinctive little puff.

Apparently you can fit seals without pulling the head if you have nimble fingers and read up on the procedure in the archive ...

Larry

 

Hi Nick,

You should not have any oil collecting in the plug wells after the new cam cover gasket set. You should be completely dry now. A few questions come to mind: are the cam cover screws too tight or too loose, and did you thoroughly clean the gasket mating surfaces of all residue before reassembling? The torque spec for the cover screws is pretty low, and since they're Phillips head screws it's tempting to want to really crank them down under the assumption that it's more difficult to get them tight enough. But overtightening them can distort the gasket and create leaks.

For winter 10w-40 is a good choice, but in the summer you might want to consider 20w-50, which is Jaguar's recommendation for most climates.

Modern engines with low-tension piston rings routinely burn 1 qt. per 1,000 miles, but that seems high in an AJ6. One possibility is that your piston rings are gunked up and sticking, allowing more combustion chamber gas blow-by, pressurizing the crankcase and forcing more oil into the crankcase breather system to be inhaled into the intake. It might be worth replacing 1 qt. of oil with 2 bottles of CD2 Oil Detergent over the next few oil changes to see if things improve.

Hopefully others will have some better ideas.

Please keep us informed,

Cheers,

Don

 

My 92 does not use oil, although the bottom end is rather slimy. The Moneyfunnel gives an embarrassing puff and uses about 1/2 qt to 1000 miles- its slimy too, although less so since some leaks were plugged. Yet another project on my back burner is the valve seals. We shall see about that..

 

Thanks guys, very good info.

I really should take a startup video tomorrow after the car sits overnight. I say 45 seconds because that's about how long the cloud of smoke usually lingers, but it may be shorter if I focus on what's actually coming out of the exhaust pipes. Stay tuned for that.

I'll definitely try the oil detergent, Don, and see where that leads me. Is this something that is added *after* an oil change, or something I would be adding perhaps 100 miles *before* the oil change, then filling the engine with new oil only?

Back in High School, I remember my shop teacher mentioning adding a quart or so of ATF just before an oil change to clean up engine deposits.

Before I purchased the car in 2013, my great aunt ONLY drove the car in the Summer, meaning here in Rhode Island, the car sat garaged and lifeless most of the year for 18 years. While she and her husband were very good at auto care, I doubt they did anything like "fogging" the engine or dropping a cap full of oil in each cylinder before storage.

Not sure if that would cause ring issues, but it seems to have always consumed oil; it was the first thing my great aunt told me when I wanted to buy the car. "You do know that it uses a bit of oil, right?"

Any improvement will be great. I appreciate all the help

Nick

 

You can do it either way: add CD2 leading up to an oil change or at the time of the change. Since your car is using oil, you could just wait till it's 1/2 quart low and add a bottle of CD2, then repeat when it's 1/2 quart low again. I usually use two bottles of CD2 as a replacement of 1 quart of oil when I change the oil in our '93, but only 1 bottle of CD2 in our other vehicles that only hold 5 quarts of oil.

 

As mentioned, gummed up rings is a distinct possibility.

You might want to consider using Shell Rotella 15W40 for a
couple of changes. It is good oil, and high detergency. The
oil will come out BLACK. No worries, that is stuff suspended
in the oil that would have stayed in your engine. It is at
least as good as the Castrol GTX and probably about the
same price.

You might also want to search on the usage of TC-W3 two
stroke synthetic marine engine oil as a fuel additive at a
concentration of 1:500. It must be TC-W3 rated. There are
many stories of it clearing up smoking vehicles by freeing
up sticking rings and acting as a top end lubricant.

 

I had a Supra like that.

I called it automatic rust proofing and left it at that.

I also figured I was getting a defacto oil change and only
added oil ... no changes.

It was pulling like a freight train when I sold it. Still miss
the 5 speed, LSD and turbo.

 

Whenever I "rehome" a vehicle, I always have a twinge. They are so complex as to have near- personalities. And the puff of smoke, while its embarrassing, is to the right rear of my back burner (I'm left handed) and under some other stuff like getting the furnace ducts cleaned and clearing the weeds from the Ivy bed under that tree. Its a very cramped place, my back burner.

 

As promised, a cold-start video of my XJ6:


Nick

 

Nick,

What was the ambient temperature when the video was shot?

Don

 

you can borrow my trick ... stack 'em higher using milk crates and cardboard boxes

 

40 Degrees Fahrenheit. You can hear the engine rpm surge up and down until the last of the oil is burnt.

 

I don't know if the rpm surging would have anything to do with oil in the combustion chambers but I suppose it could. I would tend to first suspect that the Idle Air Control Valve is gunked up with carbon - have you taken it apart and cleaned it? Here are some photos of the one in our '93:

Welcome to Jag-lovers - Members Photo Viewing Page

Have you pulled a spark plug or two to see if they are fouled with oil?

Cheers,

Don

 

Nick that surge sounds to me like a gunked up intake/throttle butterfly ...

Larry

 

The surging only happens when the car first starts. If I hold the accelerator to the floor (putting the ECM into flood-clear mode) and crank for maybe 5 seconds before starting the engine, effectively purging the oil out of the cylinders, the surging doesn't happen and the oil burning is much much less.

If I turn the engine off just after the last of the oil is burnt, engine still cold, then restart shortly thereafter, there is no surging or oil burning.

Nick