• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Oil?

Share this page

tony barnhill

tony barnhill

Great Pumpkin - R.I.P
Offline
So, I've got about 600 miles on the '85 XJ & when I started putting it on the road changed the oil to Castrol 10w30...I'm about ready to change it again to see what it looks like.

What do you guys run?
 
20W50 Castrol, or Valvolene, or equivalent synthetic.
 
Well, I flushed the engine (remember: 65,000 original miles; that equates to about 2,000 per year!) & changed the oil with Castrol 10w30 as a kinda "break-in" oil since its been sitting for some time....so, this week, I'll change it again & go to Castrol 20w50.
 
Always!!
 
In years past, I performed some distinctly un scientific oil testing in a series of sprigets. I always found that the oil pressure was higher with the Valvolene. Nothing bad ever happened with the Castrol mind you, but it was a comfort seeing 5 more PSI on the gauge. It was hard to get Valvolene around here, but now NAPA has it. I use that in most customer cars. All of my cars get synthetic. The XJS takes 12 quarts, so oil change time is ..uh... painful. But, at light throttle cruising I get a repeatable 25plus MPG out of the V12 at 70 plus MPH.Same with the Audi. I get 32 MPG on the road with that car. Both of these figures are way above what was on the stickers. Having the cars tuned correctly(and a little trickery on the Jag) along with the synthetic oil seems to free them up a little bit. I think that 10-30 is too light a weight for an XK engine. They were designed in WW2, and want the heavier oil. Read that "seldom read" owners manual. Glad you are enjoying the car. Like I said, "once you go Jaguar, you will never go back..."
 
In Missouri we could never get the Series III XJ6s to pass emmisions on 10W-30 oil. Seems to vaporize into the manifold and double HCs. After we did a change to 20W-50 and drove it for a while passed with flying colors. In my 6s and 12s, if I drove them in cold winters I would use the 10W-40 but changed immediately on warm days to 20W-50. If heads were ever rebuilt with Bronze guides, synthetic was forbidden due to the cohesion of the fluidsto the metal, whatever that did. Figured it just pumped it out.
 
Back
Top