Recently had an oil change and I used the Castrol 5AW-20 that is recommended in the user manual and on the actual oil screw cap of my 2008 XJ.

However, I do realize that these corporate alliances do not necessarily result in the best choice for the car, although I would like to trust Jaguar on this one.

My mechanic suggested I use a 10W-30 full synthetic next time, such as Mobil 1.

Does anybody know what the best oil type and brand would be?

Thanks for any advice

 

Did not know the 2008 specs 5w-200 oil. My 2006 recommends 5w-30.
There is a European made 5w-30 Edge available here in the U.S. Several recommend it over the U.S. Blend. Downside is it is 55.00 for a 5 quart jug. The U.S. Castrol and Mobil 1 are half the price.
The Castrol Edge 0w-40 shows West German origin. It is 26 - 27 dollars for the 5 quart jug. This is what I am going to use.
With the 100 degree heat here, a thicker oil at high temp is a good thing. It is still much lower viscosity hot than cold.
My owners manual actually shows several weight oils can be used. But the recommendation is 5w-30.
In the grand cost of owning a Jaguar, using 80.00 in oil per change is not a huge expense. I am just too cheap.

 

Taco, there are a number of variables. As far as weight goes, today's oils are not the same as they were 2 or 3 decades ago. So as far as weight goes, a 0w may be too light in summer, and even a 5w can be on higher mileage cars. At idle, you must maintain adequate oil pressure. Only a pressure gauge at idle will tell you. If the oil you use is too heavy, you can also cause yourself issues with other systems like VVT operation. So in the end, if you use a 5w-30 for example, and you have low oil pressure at idle when warm, it would be better to consider a 5w-40 or possibly a 10w-30. But it is known that a 5w-30 provides better scuff protection and better flow characteristics than a 10w-40.

As far as oil brands, that's a debate I don't want to engage. What do I use? I have used Castrol EDGE and Mobile 1 over the years, but Shell's new synthetic oils condensed from natural gas, (sold under the Pennzoil brand) is what I currently use.
http://www.shell.us/aboutshell/us-me...tural-gas.html

 

I used to drive a lot of business miles in company owned vehicles. Went to the local oil change with free wash and detail place. With cheap oil from the barrels and the cheapest filter they could buy the motors would go 150,000 - 200,000 in 3 - 4 years and still none used any oil. Or suffered lifter or bearing issues.
But in my personal vehicles I am much more ****. I believe in 5K changes with full synthetics.
Hearing of cars going 300,000 miles with no mention of oil type and service intervals makes me think it is not critical. But I still use the best oil and filters for peace of mind.
Plus enjoy working on the cars. Better hobby than golf, fishing, or hunting. Plus much cheaper.

 

The relationship between Castrol and Jag is strictly for marketing purposes and not a reflection of the product's potential superior qualities.

Asking what's the best oil is like asking what's the best beer. Almost everyone has a strong opinion but yet not one person can demonstrate that their favourite brand actually results in more half-naked supermodels appearing around their swimming pool as promised in the adverts.

Despite the availability of synthetic oils for over 40 years, there's only scant evidence that they are superior to conventional oils in a real-world demonstrable context. Go back and ask your mechanic what he bases his opinion on. 99% chance it's hearsay or another case of just believing the marketing hype.

There is no reason to deviate from the viscosity(s) recommended by Jag. Many shade tree mechanics like to second guess the OEM using their own logic of why a heavier or lighter oil should be used but again cannot produce any real world proof of why they are right and Jag is wrong.

At the end of the day, use whatever oil type and viscosity fits the OEM's recommendation. Brand does not matter. Going beyond that into the world of tribology and boutique oils might make you happy, but the car couldn't care less.

 

Good quality oil and filter and regular oil changes plus checks on cooling system goes a long way to looking after a engine I'm a mechanic and advise all my customers this and never had one back with a blown engine ( touch wood)

 

Pennzoil Ultra Platinum full synthetic: made from natural gas, $28 for 5qts. at Walmart. In my opinion, superior protection for the price.

 

Thanks for all of your replies. Extremely helpful and I appreciate your time. Overall, it would seem that the best course of action is to stick with my OEM recommendation in the owner's manual for what Jag advises, which is what I'll do.

Cheers,
Taco

 

Hi Taco,

I can never resist a good motor oil discussion!

For the record, I have always used Castrol oils in our Jaguars, for no other reason than Jaguar's recommendation, which I agree is based on a long-standing marketing relationship. But it reduces the number of decisions I have to make in life.

In our '93 XJ6 (designed for high-viscosity oil), I use conventional Castrol GTX 20W-50 in the summer, 10W-40 in the winter. In our '04 XJR (designed for low-viscosity oil) I use Castrol Edge 5W-20 year-round (purchased at Walmart for about USD $27 per 5qt jug). Similar oils from Mobil 1, Pennzoil, Quaker State and Valvoline cost about the same.

I agree with others that any name-brand oil meeting Jaguar's published specifications will be fine. There have been reports of off-brand oils failing to meet the viscosity and other standards printed on their bottle labels, so it's probably best to avoid that bargain no-name oil at your corner gas station.

It is very difficult to find unbiased information on the debate over synthetic vs. conventional motor oils. Most of the published information comes from the oil companies, the American Petroleum Institute, and other interested parties, so it must be viewed with some skepticism. That's why the quote below is interesting to me. First, it comes from Phillips 66, a major oil company; second, it presents several purported advantages of synthetic oils, but then argues that those advantages are not typically important for use in aviation piston engines:

"Full synthetics and synthetic blend oils are marketed heavily to the automotive industry because of their ability to provide better performance at very low temperatures, better oxidation stability at prolonged high temperatures and longer drain intervals. We believe those advantages rarely apply to the needs of aviation piston engines using leaded fuel or specifying a SAE J1899 engine oil."

The quote comes from this page: Phillips 66 Lubricants: FAQs relating to aviation lubricants

Note that, as far as I have been able to determine, all or nearly all modern jet engines require synthetic oils due to their high bearing temperatures. Whether the purported advantages of synthetics apply to automotive engines is debatable, but for me, the extra cost is cheap insurance in engines designed for low-viscosity oils.

Cheers,

Don

 

Now we're directly in my field of experience.

Mandatory use of synthetics in gas turbine (jet) engines is very closely tied to bearing cavity temperatures as you mentioned but surprisingly not so much for when the engine is running, but actually after shutdown when 'heat soak' becomes the primary concern. By nature of their design, the bearings most at risk are in close proximity to the 'hot section' of the engine meaning immediately adjacent to the turbines powering the compressors or fans.

While the engine is running, the bearing cavity temperatures are moderated by a constant flow of fresh, cool oil and also with (relatively) cool air bled from one of the intermediate compressor stages. If an engine were to be kept running non-stop 24/7/365, virtually any oil better than whale blubber would be suitable as the temperatures would be within reasonable values. The problem arises after the inevitable shutdown where the flow of cooling oil and air immediately ceases, while conductive heat from the turbines continues for many hours. Many internal engine components are 'burning hot' even 24-36 hours after shutdown.

The result is carbonizing or 'coking' of conventional oil inside the cavity which can block oil passages and jets leading to serious bearing issues in short order. Synthetics provide additional thermal 'headroom' so that coking is reduced or eliminated.

Such capabilities are an absolute waste on piston engines- either aviation or automotive- as such engines would be seized up solid from thermal distress long before such headroom would come in to play.

If there is some demonstrable advantage to synthetics, most are suitable to be kept in service for a longer period of time/distance than conventional oils. Given that many Jag owners apparently can't or won't take advantage of the standard OEM change interval when using conventional oils, it seems unlikely that this pattern would change when using synthetics.

Each to his own.

 

While thermal distress may be one of the many considerations, it is by far not the only consideration for using synthetics. I won't paint the current horizon of some of the advantages of using synthetic base stock with such a bleak outlook or with such a broad and superficial brush.

It's when you step into attempting to market synthetic blends. There is no regulations concerning this claim, as it may be 1% or 99% or anywhere in between to qualify. Synthetics certainly have their place, and they do provide significant advances over simple cracked base stock.

 

So we've been told for the last 40+ years. This would seem to be more than sufficient time for hard evidence from the field to surface en masse supporting such claims. And yet.........

Statistically, there's more indication that travelling salesman snake oil health remedies are of more benefit. I haven't compared Budweiser against Coors to see which nets me more bathing beauties by the pool so the jury is still out on that one.

 

My wife had a 2006 Geo Tracker. Did the oil at 3500 miles. Did an oil change at about 15,000 miles and switched from conventional to Castrol Syntec. She asked me later what I did to her car. Said it ran faster and smoother. This was primarily highway use.
Recently started doing her Toyota Sequoia oil changes myself. The local oil change/detail place always used Havoline 0w-20. At 85,000 I switched to Mobil 1. It always races on start up. The revs drop after 2 seconds to idle. During the cold start up it always made some low level banging noises. Figured it was lifters pumping up. The noise would stop after a couple seconds.
After going to synthetic it still revs up on start, but the engine noise is gone. On the second oil change with synthetic. Much quieter on cold start. Seems the same once idling.
I want to say my 2006 XJR idles quieter now with 0w-40 Edge compared to the 5w-30 Mobil 1 this was in it. The previous owner did an oil change as a pre-sale condition. They used a Mahle oil filter and the specified viscosity oil. But this might be wishful thinking on my part.
The Geo Tracker example was real. The wife did not know I had changed her oil. She just knew the car ran better.

 

Well, one bit of arguably hard evidence is that not all that long ago, auto manufacturers specified oil change intervals of 3,000 miles/3 months. Yet, for our '04 325i, BMW specified the use of (Castrol) full synthetic oil and a change interval of 15,000 miles/24 months. BMW recently revised their recommendation downward to 10,000 miles/12 months for cars produced from July 2013, but that is still significantly longer than the intervals recommended when conventional oils were specified.

And on the topic of marketing agreements, in November 2014 Shell announced that it had been selected as BMW's recommended oil supplier and that from January 2015 its full synthetic oils would be available at BMW dealers, but in May 2015 Pennzoil made the same claim...

 

Pennzoil is the US subsidiary of Shell, (Shell owns both Pennzoil and Quaker State) and in the UK it is marketed under Shell's branding. Same stuff.

 

3000 mile/5000KM oil changes have not existed in decades.

My '03 S-type has a 10,000mile/16,000KM change interval when using conventional oils, as do all Jags of the era. No synthetics required or recommended. My '04 Lincoln SUV has the same interval and requirement.

SWMBO's 2011 BMW X3 also has a 10000mile/16,000KM interval but specifies synthetic. No option to use conventional. Progress?

 

Actually, for our 2005 Town & Country, Chrysler specifies 3,000 mile oil change intervals for many if not most drivers. When you get to be my age, 10 years is "not all that long ago."

 

I presume that 3000 miles is the severe service interval and 6000 would be the standard. This

Tech Feature: Family Ties - Servicing Chrysler's Versatile 3.3L and 3.8L Engines

seems to agree.

Something interesting:

"In 2004, Chrysler revised the recommended oil change interval for normal service to 6,000 miles (which is probably still too long for most urban drivers). "

Comparing the severe interval on one car to the standard interval on another is apples and oranges.

 

Actually, our owner's manual does not use "severe/standard service" terminology.

It states:

"Check the following list to see if any apply to you:" The long list includes such common conditions as "Day or night temperatures are below 32F (0C)," "Stop and Go driving," "Short trips of less than 10 miles (16km)," and "Extensive idling." Those conditions hardly seem "severe," and Chrysler doesn't treat them as unusual. They all apply to our family and probably to millions of North American drivers, if not the majority.

The manual continues, "if ANY of these apply to you (ANY is capitalized in the manual), then change your engine oil every 3,000 miles (4,800 km) or 3 months, whichever comes first.

If none of these apply to you, then change your engine oil every 6,000 miles (10,000 km) or 6 months, whichever comes first. NOTE: Under no circumstances should oil change intervals exceed 6,000 miles (10,000 km) or 6 months, whichever comes first."

 

Yup, that's similar to most OEM's definition of 'severe service. Here's an interesting article on the topic:

Are You Normal or Severe? Learn Which Oil Change Interval is Best for You

Given the high percentage of owners who apparently unknowingly or deliberately ignore the severe service schedule, it seems strange that the failure rate of engines due to lubrication issues is almost zero.

I know from my own work in the aviation field that the suggested intervals are conservative to the point of being painful. I wonder of the same applies to the auto industry?

Maybe this sheds some light

Changing Definition of Severe Service | Passenger Car Motor Oil (PCMO) - Gasoline Cars/Pickups/Vans/SUVs | Bob Is The Oil Guy

Wherein Ford, Toyota, Honda and others have modified their definition of 'severe' to the point that almost all drivers now qualify for 'normal' interval.

Maybe Chrysler is overdue for a review?