Has anyone had any experience with Royal Purple synthetic oil? What is the best synthetic oil?

 

Some people swear by the smaller "boutique" oil suppliers like Redline or Royal Purple. I've always had more confidence in the bigger names - Mobil, Castrol, Penzoil.

 

I didn't think ANY synthetic was on the list of recommended oils for Jaguars.

 

Using oil analysis we run Amsoil in our 2002 XKR with 20,000 change intervals.

 

+1 on the oil analysis. With engines as expensive as they are on these cars, I think the twenty bucks extra for the test is well worth it.

You really go 20k? I was only planning to go 10k on Mobil 1 5W-30 (with a filter swap at 5k) but maybe I can stretch it.

...and if I had a nickel every time I read about what some manufacturer recommends....

 

That is true for any late model owner's manual I've read (Haven't read them all, but many). Jaguar has either been silent on synthetic oils or specifically warned against them. Here is a copy paste from a 2002 MY:

Recommended engine oil

When the oil level is at the lower dipstick mark, add 1 quart (1.0 litres) of oil.

Oil specification

Note:

SAE Viscosity Rating

It is recommended that you use only approved engine oils to meet the SAE viscosity range/ambient temperature scale shown below.

For maximum fuel economy, 5W/30 oil is recommended.


Although it caused a lot of controversy the last time, I'll chance a restate -

I very much believe in the oil analysis and the interval in my XK8 is 12K with an extra filter only or two interim change at 4K or 6K miles. The last oil analysis I had done showed I could have extended the change to 20K miles. Most of my customers have gone to analysis with extended changes and I have had some of these cars in my care since warranty end. I only have a couple of clients still doing 3K or 5K changes, but they also don't "buy" the oil analysis for some reason. Old habits die hard.

 

Oil analysis technology has it's place, but must be used properly to have value. I do not believe that a single sample will necessarily give an accurate picture of an engine's health each and every time, much like a single blood pressure reading will not confirm whether a person is/is not in good health.

I am retired from a 31 year career in the aircraft engine business, primarily in the customer support engineering end of things and frequently observed that individual oil analysis readings gave false results, either positive or negative.

In the case of a car engine, the cost of the testing would outweigh any potential savings achieved by extending the oil change interval.

 

Yes, using Amsoil Series 3000 0w-30. Started off with a 10k interval and gradually worked up. Our 98 XJ8 likes to be changed around 12,000 though.

 

Woe is me no common answer

 

I have never believed the hype from oil products and I have real world proof to back it up.

My 95 Volvo T5R went to 356k miles and was still going strong when I sold her, engine had never been cracked.

93 vette was at 203k when I sold her, was leaking at rear seals, but could still hit 130 mph (did this twice, once right after I bought it and 2 months before I sold it), car ran great.

All total, I have had 6 cars go over 200k miles and none have ever had synthetic oils or boutique oils.

You ask how I put that many miles on my cars, I worked for just over 10 years at a job about 120 miles from my house.

 

It really doesn't matter what kind of synthetic, or dino oil you use. All that really matters is that you regularly service and maintain your car.

Which method is better? The one that you can follow the best.