Took my 2007 XK convertible to the dealer for its first oil change under my ownership. 36,000 miles. Biggest reason was to be sure the correct oil would be used. A couple of days later, I noticed the reminder sticker on the windshield had 10W 30 for the oil. I thought for sure that 0W 30 or 5W 30 would/should have been used. My question is....on my next oil change, do I ask for 0 or 5W 30 or let them continue to put in the 10 wt. or take it somewhere else. May not be a big deal, but made me a little uncomfortable. Also, do you really know what oil they are using?

 

The 4.2L engine oil viscosity spec is 5W-30. I doubt that 10W-30 will do any harm except possibly lower fuel mileage. What does your invoice say? It's possible that the windshield sticker is wrong.
https://www.jaguarforums.com/forum/x...09-xkr-147625/

 

would say 5w30 is the correct oil for your car . full synthetic

 

Invoice only says Castrol GTX, no weight stated. Next time I'll specifically ask for Magnatec 5w30 or similar and hope they have it. Personally, I would feel better with a full synthetic. When speaking with the service guy, he did say that regular oil (not synthetic) is what is recommended. Seems to me if it was that important, they would have at least used the correct weight. I do agree with you Stuart, 10w30 would be OK, but if 5w is available, I'd much rather use it

 

Synthetic is not necessary for the 4.2 unless you want extended change intervals or drive the car hard and need better molecular stability. Although the cost of synthetic is fairly comparable to to conventional. I use Castrol 5W30 Edge with titanium full synthetic at less than $5 per quart.

https://recondoil.com/synthetic-oil-guide/

https://www.youtube.com/watch?v=tYkg...ature=youtu.be

 

Note that the choice of engine oil is far more critical for the 5.0L engine, which has an issue with premature wear of the timing chain tensioner ratchet. To improve lubrication at startup, and increase the life of that ratchet, Jaguar changed the recommended viscosity from 5W-20 to 0W-20. Note that this applies to the 5.0L engine, and not the 4.2L.
https://www.jaguarforums.com/forum/x...il-car-214892/

There's more to choosing the right engine oil than just the viscosity. Additives are critical, so make sure that whatever oil you decide to use meets the Jaguar specifications for your engine. The latest 5.0L oil spec is STJLR.51.5122.

 

I won't be driving hard at all. I always change at or before recommended intervals....3,000 mi max for conventional and 5,000 max for syn. I do think I'd like the extra protection at start up that the 0w or 5w would give. The 10w is the question I have. Why would a dealer use it?

 

The 0W-20 is for the 5.0L engines, not the 4.2L. Your 2007 is a 4.2L. Jaguar dealers usually buy Castrol oil in bulk, and probably have more than one viscosity/spec oil for different JLR engines. The 5.0L engines use 0W-20, not 10W-30.

You need to call your dealer and ask them why they used 10W-30 instead of 5W-30 as specified in your Owner's Handbook. Did a Jaguar new car dealer change your oil or some other dealer?

 

A Jaguar dealer. Before I take it back there, I'll ask if they have 0w or 5w. If not, there is an independent shop with really good reviews that I will check out. I know it's not the end of the world, but I would like to use what is specified.

 

When you take your 2007 XK back to that Jaguar dealer, I suggest that you show the service manager that 10W-30 window sticker and ask them to do an oil and filter change using the proper 5W-30 oil that meets Jaguar specifications at their expense. If they tell you that 10W-30 is OK, ask them to show it to you in writing from Jaguar in a Technical Service Bulletin. They used the wrong oil and should correct their error at their expense.

You probably paid over $100 for a $30 oil change, so they can well afford to eat that cost and still make a profit.

 

That I know of, no one has provided proof that Jaguar US has dictated a shift to 0W-30, so from anything posted on this forum (that I am aware of) 5W-30 remains recommended weight. Several other countries do drop to 0W-30, but I suspect it may be weather (cold temps) related.
Jaguar does state that 0W-30 is backwards comparable to older cars, but the "required" change is not official for US owners.

10W-30 should not harm an engine, and in hot climates (southern States), I would probably consider it myself. Fuel economy should also be negligible as once the block comes up to temp, your oil is warming to the 30 weight rating.




P.S. I buy my Castrol Edge at Wally World, and my filter from Rockauto so I know exactly what goes in and on my car. My local independent shop just charges me $20 to drain and fill with my oil.