Oil Change, 5w-30 or 5w-40?
 

Getting ready to change my oil since taking ownership back in October.

I've put about 5K on since purchasing and figured I'd change it.

After looking through the owners manual I noticed that 5w-30 is preferred but will only protect from -22F to +95F. According to the manual it is recommened for the best fuel economy, not that that is much of a concern as I would prefer protection over fuel economy.

I know the summers here can hit the 100's so I expect the 5w-40 would be better as it says it will protect from -22F to +122F.

they also have 0w-30 and 0w-40 listed which increase(decrease?) the low end to -31F.

Not really looking at brand of oil as I have been very happy with mobil 1 and used that in my 97XK8 and also my wife's Charger.

Expect I will change oil twice a year so summer/winter.

So what do you guys use or do?

I know you stated that you were happy with Mobil 1, but just for reference (and because you said you were looking for perfection) Jaguar has only recommended Castrol oil since at least the late 70s.

As for the grade, I use 5w-20 actually, as this is what is called for with the S/C 5.0L (2012 XKR-S). No alternatives are offered. The 5.0L engines require a very thin oil, and using ANYTHING other than the Castrol SLX Professional OE 5w-20 will void your warranty.

However, my 2005 XK8 has the N/A 4.2L, same as your 07. I use 5w-40 for the same reasons you mentioned above- better hot temperature range. I also use the Castrol SLX professional for this car, although the 4.2 isn't as picky as the 5.0.

Completely up to you, but I've read that some of the newer Mobil 1 products don't meet the standards set by BMW, Audi, and Jag/LR. Just some food for thought.

Use the viscosity that best suits your climate and the API rating required by Jag. Brand is irrelevant.

Twice yearly changes are excessive unless you're exceeding the mileage limit (unlikely)

Always important to read the fine print :)

In IL, you could probably run 15W40 Shell Rotella year round.

Castrol and Valvoline also have 15W40 HDEO's in their product
lines.

Unless you put on a lot of miles, annual changes would probably
be good enough since the engine has a big oil capacity to
disperse and hold contaminants.

edit: your sig and post only mention a 1997 XK. if it is one of
the other models requiring the 0W20, then all bets are off.

agreed

Got a reference?

Try this,
Castrol oil selector,
http://oilselector.castrol.com/c/uk/eng/search

I pay £28.00 for 4litres, what is the US price for this oil.

Interesting, the UK site and US sites give different answers (for an '07 XK), maybe its just a branding thing.

UK: EDGE 0W-30 A5/B5
US: Castrol EDGE Extended Performance 5W-30 or EDGE 5W-30

Can't seem to locate a seller for the UK answer in the US.
Looks like Walmart sells the Castrol EDGE Extended Performance 5W-30 in a 5 quart bottle (4.73L) for $28.68. The Castrol site says the car need 7 Liters.

Talking as a engineer I find a lot of the oil discussions amusing. Use what the manufacturer recommends, that's what they tested. Not all engines and not all oils are the same. I know manufactures can f### up but there less likely too than you or I are second guessing there extensive testing.
I've had great results with Mobil 1 on Porsche's and wouldn't run anything else but if Jag recommend Castrol then I'll go with that. My point isn't that Jaguar chose castrol necessarily because its better (it may well be a business / sponsorship deal) but because thats what they tested with.

Yes you are correct! The only reason Jaguar wants you to use Castrol is their business relationship with them.

Castrol is a plenty good oil just not the only one.
.
.
.

I like to drive my car good and hard, using the padels all the time, so i don't mind a bit of oil usage, i know the superchargers engines are pron to a bit. I used to use the castrol edge 5w30, and it used a bit. I decided to switch to castrol magnetec 5w30 and no oil usage, so i don't know.
My dad has a 02 Dihatsu jeep that he has used on contract jobs and pulls a trailer every day. He used castrol for the first few years and it burned some oil. He switched to esso and burned none, color didn't hardly change during changes.
As long it is the right spec that's the thing.

Thanks for the input guys and I'll look into the Castrol as they do recommend. It's funny, there was a bit of a heated discussion in the X100 forum about oils and wasn't trying to start something like that here just interested to see what others are using.

There were charts and all kinds of fun stuff and one member gave me crap because I was using royal purple at the time which worked very well, car ran silent, couldn't even tell it was running at idle, later switched to mobil 1 due to expense as I was up in mileage and loosing some oil between changes.

AMS oil was at the top of the list, then mobil1, etc. If you're really interested I'm sure you can do a search in that forum.

And yes it may be a little overkill to do twice a year but it is a daily driver for me and figure I'd just change the oil when I do the tire swap.

Plus it gives me a chance to get under the car and do an inspection, touch up or maintenance. It's not like the oil change is that expensive for the 4.2 unlike the 5.0l from the post I just saw $350.00 wow, bend over. I saw where they do have like 9qts in there though.

However, I will miss the ease of oil change on the 4.0L in the 97XK8. Didn't even have to raise the car, oil plug and filter were right in the front. Just slide a pan under, drain, change the filter and top off.

Thanks again for the input.

How about acknowledging that almost all engineering involves
compromises?

Often due to non-technical criteria such as budget or supplier
allegiance.

Agreed, All engineering is a compromise which leads to my point. I'm concerned less about matching specifications and more about test results. The problem is bearing design is almost never ideal (true of any design), this along with a wide variety of conditions means you choose your design, materials and lubricants based on specifications, date and experience then you test.
Any Engineer who has conducted a large amount of testing will tell you that test results can throw up some surprising results from superficially similar products.
I'm sure jaguar chooses Castrol because of the long business association as does Porsche with Mobi; etc. But that is is what they designed too and tested with.

You've made a very large assumption.

It is a assumption. But what ever the reason for choosing a supplier (as a engineer I am often frustrated by this) the choice of the oil spec will be a engineering decision and it will be what they tested with.

Yes 'spec', not necessarily 'brand'.

Did some research online and found 5w-40 isn't very easy to find. Went to the different sites for each oil and and used their selector, mobil, castrol, and even penzoil. Checked penzoil because I found some charts on the AMSoil site about 5w30 oil testing.

Here's the link if your interested

AMSOIL Performance Testing Archives

Mobil and Castrol performed the worst in the four-ball wear test?

Another site not related to penzoil or AMSoil actually like the Penzoil Ultra over all three, Ranked it higher than AMSoil because of cost. Sorry I don't remember which site but it was some independent thing.

Mobil site selector listed 0W-30, 5W-30 and 0W-40, no listing for 5W-40.

Castrol listed all the weights and recommended Castrol Edge

Penzoil didn't even have the 2007 XK but if I went to a 2006 XK8 they had listings similar to mobil 1, no 5W-40.

So if I want to use 5W-40 it looks like Castrol is the way to go. 0W-30 and 0W-40 was called a European formula by a few of the brands and all brands did carry that.

Also my car was considered severe duty as I found some fine print about less than 10miles trips are considered severe duty and mine is 6miles each way. Which would require more frequent changes as I may get moisture build up or contaminants because the oil doesn't get hot enough with short trips to burn of excess moisture.

Again I didn't want to start anything about brands as each person has their own preference as to what they use.

I expect all the major brands are fine but change interval is most critical IMHO.

Stopped by napa and couldn't find 5w-40 on the shelf and had a quick discussion with the guy behind the counter about oil. He was surprised when I mentioned the Penzoil Ultra as they don't even carry it. Said when it first came out they stocked it but the people preferred the standard penzoil so they stopped carrying it. He did mention that they change their fleet vehicles every 5-6K as 10K is way to long for most vehicles but I expect they are also considered severe duty.

Thanks again for the input and who knows, I'll probably stick with 5W-30 if I can't find the 5W-40 readily available. Owners manual just threw me for a loop when it said 5w-30 is only protects for temps below 95F degrees.

FYI as Audi recommends this VW spec oil it turns out that it is Castrol 5W-40 . This is all I use in my kids A4 and it is pretty available in most of our auto store outlets.

I'd almost guarantee that Jaguar did there testing with the spec and brand they recommend and not a different brand to the same nominal spec. I'm not sure I can recall the number of meetings I've been where some has complained about test or field failures. When you ask did they change material etc they say yes but the supplier assured us it met the spec. My point is there can be big differences between different supplier material or oil of the same nominal spec. The problem is when things past test you don't normally know why and there is never time to say well what if we change something to see if it fails. So unless you have test failures you don't normally explore in detail. Bottom line don't change things unless you have a good reason, and if you do redo your testing.