Using oil
 

1996 XJ6 VP.
Will drive 200-500 miles and uses 1/4 quart of oil.
Dip stick a M level
Gets below after road trips.
No leaks.
Any ideas?
Going to add some BG products before next oil change.
102k miles on the OD.

Hi Godspeed,

For comparison, modern engines with low-friction piston rings can use as much as one quart of oil every 1,000 miles or so. The owner's manual of a Mercedes E550 I service states that, depending on driving conditions, the engine can use a quart of oil every 640 miles. So by modern standards your oil consumption is not excessive.

If you feel your oil consumption has increased, the first question that comes to mind is whether you are using the correct oil viscosity. I am attaching a TSB with Jaguar's revised oil recommendations. For most temperate climates, summer oil viscosity should be at least 10W-30 and ideally 10W-40 or heavier. Use of lower-viscosity oil can promote increased consumption.

Another possibility is that your crankcase breathing system is obstructed, causing positive crankcase pressures and oil being forced past the piston rings. The crankcase breathing system is designed to maintain a slightly negative pressure in the crankcase to reduce windage and other issues, but if the system becomes obstructed, combustion blow-by gasses can cause high positive pressures in the crankcase.

Cheers,

Don

Hello Godspeed, Have you cleaned your throttle body lately? There is a hose that connects from the cam cover to the bellows before the throttle body. In the fitting on the bellows is a brass dish that causes the depression that
Don B the moderator is speaking of. If it is missing after a throttle body service, Up goes your oil consumption. Also, Changing your oil sooner rather then later can reduce your oil consumption.

Larry Louton

Thank you Don.
I am going to take the PCV off and clean it out.

Thanks Larry.
I am going to clean the PCV and I am unsure if the TB has been cleaned as I have has the Cat for 3 months now.
I am using 10w 30 Mobil 1 oil for the summer months.

I took apart the PCV and throttle body plumbing. Cleaned thoroughly. Wasn't terribly oily but much better now.

Good job, Godspeed!

For the benefit of other readers who may find your thread and go looking for their PCV system or valve, Jaguar does not use the term Positive Crankcase Ventilation, nor does the AJ16 engine have a PCV valve. Jaguar uses terms like "Engine Breathing System" or "Crankcase Breather System" in the parts diagrams and Workshop Manual.

Please let us know if the cleaning seems to have made a noticeable difference.

Cheers,

Don

When I worked at the dealer here in Texas, we used bulk (250 gallon tank) Mobil 15W40 for all the old inline 6 and V12 engines.

5W30 for the later V6 and V8 engines.

I used Castrol 20W50 in all my 4.2 liter XJ6 and 4.0 AJ6/16 engines.

bob

Interesting choice on the 20w50 oil.

20W-50 was Jaguar's recommended viscosity for the AJ6 engines in most climates, and it makes complete sense for use in the AJ16 in Bob's home state of Texas. As I mentioned earlier, I'm an advocate of using the heaviest viscosity recommended by Jaguar for your climate.

When I obtained my first AJ-16 in 2010, I promptly accomplished an oil change, putting in Valvoline, 10w-30 synthetic. Ever heard the phrase that ends in "...Like (excrement) through a goose?" After talking to Bob, I've been a happy camper on 5W-40 synthetic ever since.

Update,
Driving down the interstate at 80 mph with a red Lexus behind me I noticed exhaust smoke from the tail pipes in
my rearview mirror. (possible cause of oil consumption 102k miles AJ16)
What is a common cause of this?
Valve cover leak?