What oil do you use?
My 2004 XK8 says Castrol 5W-30 on the oil fill cap. I don't know if that means synthetic.
I live in Oklahoma. Hot summers. Somewhat cold winters.

 

Supertech 5W30 full synthetic.

 

Isn't that Walmart oil?

Also, tell me about the LSI pressure release valve.

 

Supertech is Walmart oil.
Here is a link to Gus's site for the LSI pressure release valve.
JagRepair.com - Jaguar Repair Information Resource
While I respect the folks on this forum having differing opinions for both engine oil and devices to cope with the convertible hydraulic pressure transient response and limits, this post reflects my opinion.

 

I run Castrol GTX 5W-30 conventional oil. The car has 122,500 miles with no engine issues....

 

According to the oil guildlines in my owners manual for a temperature swing like my Northeastern Oklahoma, the suggested viscosity is 0w-40. I use the same oil (Mobil 1 0w-40) summer (+110 F) and winter (0-10 F).

So far I’ve used it for the 51,000 miles the car has been in my garage. I have zero oil consumption with oil change intervals of 5,000 miles. According to the Blackstone Lab reports, the oil has about 50% of the additive package left when changed at that mark.

total mileage on the car is 169,511.

Z

PS the excellent wear characteristics of a quality synthetic oil make choosing Mobil 1 0w-40 a no brainer.

 

i use 0w-40 all year. My preferred products are Castrol Edge European Formula, Mobil 1 European Formula, or Amsoil European Formula. The last is an expensive proposition, while the first has all of the same detergent benefits. having great results with the Castrol Product. No wear indications in the oil analysis. I wrote a few comments here explaining the European Formula. Take a look, might be interesting. For filtering, i use the Royal Purple branded filter.

 

Are those European formulas easy to find in a local auto parts store?
Regarding the 5W-30 Castrol Euro, I see a 5W-30 C3 and a 5W-30 A3/B4. Which one, if I chose to use this weight of oil?

 

one can find them anywhere. Use the A3/B4, however it will say European Formula. Be careful if experimenting with other Euro spec oils as these have lower SAPS than the ones that i mentioned, defeating the purpose. See my other posts elsewhere. Think of SAPS like the old Zinc, solids that help with boundary layer lubrication. If i said this wrong, please someone correct me. You get the idea anyway.

 

I'm kind of an old sap.

 

I get the Mobil 1 0w-40 European formula at Walmart-. About $23 for 5 quarts.

Z