After searching the owner’s manual and service recommendations from various Jaguar sites, there seems that oil change service intervals are not well defined. I have had a practice of using 5W30 conventional on a 2500 mile interval with conventional filter over the last 25 years.

I do use synthetic on the boats and a corvette that is driven rarely, in that I feel it maintains stability over long periods of inactivity. I have seen the acid development on the bottom of boat engine oil pans and oil connections.

I also have driven 5 vehicles over 400000 miles by using the above interval and conventional oil, what I find is that at 2500 miles I can really feel the weight difference in new and old filters when I change the oil, and when I go much over 3000 miles the oil begins to thicker and sludgy.

Looking here to see what I need to know, what experiences other X Type drivers have had and what recommendations you might feel important to bring to the discussions. To those that have newer cars which are recommended to the high mileage frequencies and Intermediate filter changes, I understand the need for 0W40 synthetic oils, piston ring clearance concerns, and oil ring lubrication … but in my mind we are not dealing with these concerns on the X-Type. Please adjust my thinking if you feel the need.

 

My experience is with 3 X-Types. I change the oil and filter once a year, which represents about 6000 kms of use and I use only the Jaguar-specified Castrol 5w30. The oil stays pretty clean, and I have never had an engine problem of any kind. I use only the Jaguar OEM filters.

But you mention the difference in weight between a new filter and your used filter and you imply that this difference is the weight of dirt trapped by the filter. I suggest that it is much more likely to be the weight of the oil absorbed by, trapped by the filter element.

 

The factory oil change interval is 10K miles or annually when using conventional type oil. The recommended viscosities are shown in your owners manual.

There is no evidence indicating that this interval is in any way adventurous or excessive. 10-15K miles is very common amongst modern day cars.

There is also no evidence that using synthetics on cars designed for conventional oils has any benefits.

 

Terry, when I had my X-Type, I ran just about everything out there. I did not see any difference in the oil at the oil change or in mileage when switching between full synthetic, a blend, and straight conventional oil. So, what you use is up to you.

As for interval changes, some members here believe in the 10K mile oil changes, others have adopted 5K mile changes. I kept and eye on the mileage of the car and I noticed mine would start to drop slightly when I hit 4K miles. So, that was the interval that I went with. With my XJ, I have bumped it up to 7500 miles between changes.

As for weight of oil, with the variable valve timing, sticking with the recommended 5W30 oil is highly recommended in my book. Jaguar has come out and said that running 5W20 oil is fine too. So, that is up to you. This also assumes that you don't put in any oil additives. These can thin the oil or thicken it. So, know what you are putting in the engine. This engine can start developing issues if you get too thick of oil into the engine.

 

Spot on Chris.

 

"There is also no evidence that using synthetics on cars designed for conventional oils has any benefits."

This is my personal experience. My 1997 Ford Explorer 4.0L SOHC that I have owned from 30,000 miles (1999) and serviced it myself every 3 months. Around 150,000 miles it developed many problems, loss of power (50%) poor economy , rattles and pinging. This all pointed to the hydro timing chain tentioner, a common problem. I bought a new motor ($2K). What the heck lets try some Mobile One 5W-30 oil. With in 1,000 miles everything went back to normal, but still has a 25% power loss. The oil must have freed the chain piston up. I have put 60,000 miles on this motor for it to blow up so I can install the new motor. The new motor sits on the stand in my shop waiting for its day.

I use Mobile One in everything. It can't hurt.