Er... so you'd stick to dino oil?

To me, Mikey was quite specific but you weren't. The point being?

 

Not at all. I can think of only a few engines that have that need and certainly our S-types do not fall into that category.

The first piston engine that I ran across where synthetic oil was mandatory was a low/moderate performance 'old school' pushrod V8. No DOHC, no turbo, just a design decision to specify synthetic versus replumbing the engine compartment for an oil cooler.

 

Are you replying to me? My point being that the reasons for using synth in certain turbocharged engines apply to some degree IMO, to most modern high-spec engines.

 

But not to ours, apparently, since Jag specified non-synth and 10K mile intervals.

 

I always use SYNTH oil for all my cars anyway. I used CASTRO GOLD bottle one the 5w30 SYNTH and K&N oil flter for 10k oil change.

 

Guys, what is the deal with Jag not recommending synth oil for the S Type? Has anyone ever had an issue with this? I would rather use synth than petro oil (but the service mgr told me it was not recommended).

 

The following appears in the 2002 owners manual

"Note: Jaguar does not approve the use of synthetic engine oil in the V6 engine."

and does not appear in 2003 and subsequent manuals.

 

As far as I know, local Jag dealers use Castrol Syntec Blend 5/10W-30 for most (if not all) jags they work on.

 

I always thought synth oil only necessary in turbo engines since the oil helps cool the Turbo in most applications and Dino oil can't handle the temps.

 

Hmm. The Driver's Handbook for the 1999 3.0l does not mention synthetic as opposed to mineral, and has this to say regarding the oil type:

Oil Specification: API SJ / EC and ACEA A1-98 or A3-98

..together with the usual SAE viscosity/ambient temperature table, with 10W-40 recommended for hot climates and 5W-30 covering most usage.

 

The Brits dont have the Padantic historic folklore about oil changes as the USA ( Yes a 55 straight 6 Stove bolt Chevy may have need an oil change every 2 weeks or 2000 miles ) BUT Modern engines , oils & filters preclude that old notion .

With anycar I have had for the last 10 yrs its been the usual British Interval --every 12 months or 10--12.000 miles .

I just sold a 1.6 THP 140 turbo Peugeot 3O8 ..Recommended oil change 2 years or 20,000 miles . & this engine is more complicated than any Jag engine .

 

hehe, you're right we're not so pedantic about oil.

I'm sure synth is OK, just not required (for the petrol-fuelled cars - the diesels are so very very different that I'd be wary).

I figure Jag tested the (petrol) engines with dino oil and know they're happy with it.

 

And there's part of the mystery- the cars over here never actually needed frequent oil changes either. I can only put it down to garages trying to upsell their customers with needless maintenance.

One of the corner garages where I used to live tried doing a guilt act on me because I was not doing 3000 KM oil changes on my cars. They suggested that not only do I need to change the oil at that interval but would require a complete engine flush each 6000 KM 'just to be sure'.

I went out of my way to steer business away from them as much as I could.

 

Finally! Someone who reads the entire specification and not just the throwaway blurb about "best fuel economy".

 

Of course it is. As long as it meets or exceeds API SJ / EC and ACEA A1-98 or A3-98. That's pretty much every synth sold.

I'm quite satisfied with Shell Rotella 15W40 conventional heavy duty oil which meets API SJ along with its diesel ratings. The 10 quart jug is just right for a complete change and available at heavily discounted prices.

 

Standard dino is more than up to the task-while the engine is running and the oil is recirculating. The problem is after the engine is stopped and the residual soak back heat in the turbo unit tends to carbonize the oil. Synthetic has the extra head room, dino sdoes not. Such conditions do not occur inside the engine itself, so this characteristic of synthetic is of no real value.

Even if a person were to read and memorize the entire spec-it helps little when choosing an oil for purchase only to find that the spec is out of date and the product is no longer being manufactured. Later owner's manuals reflect the discontinuation of API SJ oil and recommend API SL instead. The SJ spec in turn is also out of date having been replaced by API SM.

Is SM backwards compatible with SJ and SL? The API says yes, yet it is know that the reduced concentrations of zinc and phosphous can be detrimental to flat tappet camshaft engines (not a concern on our S-types)

Just adds another layer of complexity to the subject.

 

I remember Saab strongly recommending synth oil when I had my Aero 9000 turbo, for that very reason. And I also see that Jag makes no mention in the manual of the need for synth oil in the S-type or STR.

So, Jag says that a supercharged STR does not suffer from oil coking or heat soak-back problems after a hot shutdown. Even if they are 99% correct, the increased oil-change intervals and more stable viscosity makes me prefer to use synth oil. Am I wasting my money?

 

The more stable viscosity, even if true, has no apparent benefit in engine reliability or longevity, so that has no value for me.

An extended oil change interval might help save money or avoid waste- but what interval have you chosen and how did you determine that it might be appropriate? Jag gives no credit for those using synthetic vs. dino.

Given your ongoing admonishments to those that discuss deviating from Jag's octane requirements, reading your comments above is a surprise.

 

The API and equivalents are far better qualified to make that declaration than any one on this forum. And it is their declaration to make since it is their publication.

API SJ/SL are still currently available, notably in heavy duty conventional oils such as the above mentioned Shell Rotella, Valvoline Blue, Mobil Delo and Castrol.

There is nothing complicated about the Jaguar specification at all. It is one line referring to an industry specification. What adds complication is people swanning about insisting that their opinion couched as pseudo-science is somehow more relevant, exacting and learned than the specification and the mandated laboratory testing.

Since you have not bothered to point it out, any oil rated at greater than W30 has relaxed limits for ZDP. That includes W40. So for those insisting on thin winter weight, the vendor data sheets to look at would be the 5W40 heavy duty oils like the Shell Rotella 5W40 synthetic.

Finally, if someone needs to ask what oil to use, then they are not qualified to deviate from the specification found in the owners manual. Following the specification is perfectly safe. Listening to the advice found on the internet without critical evaluation is not perfectly safe.

 

Yes, that is annoying isn't it.