Very interesting thread and very educational. I learned the meaning of the word " Onanism" but I'm pleased I didn't ask the Wife to look it up

I have a shed full of classic motorbikes which sadly don't get used as often as they should and I tend to change the oil when it starts to look a bit dirty. I'm thinking I might adopt the same philosophy with the cars. I just changed the XK oil after one year and 3K miles. It was as clean as when I put it in. On the other hand I would have to change my wife's Range Rover diesel's oil every 5 minutes to keep it clean so you have to be realistic.

Great thread.

 

Mikey...if you checked my posts you'll see that i did extensive research within the forum and out to find out what the key factors in XK8 engine failures are/were...proper interval fluid renewal was one of the those key factors.
I'd be interested to find out what research you did to be able to factually state:

"The sheer number of owners who used the factory recommended type of oil and viscosity and followed the recommended interval without issue clearly points away from Jag having gotten it wrong."

What does this mean today?

 

I know that there are many that arbitrarily cut OEM intervals in half or even less- but that doesn't translate into proof that there was a need or benefit.

If you dig further- there's little evidence of lubrication related failure of any type on this engine series. This includes the many owners who followed the OEM recommendations for oil type and interval.

In other words, there's no real trend I can find of engines suffering reduced reliability or durability by following OEM recommendations vs. those who chose a more conservative route.

Unless you can show me otherwise.

 

I firmly believe that the failure of my original engine was from the IPOs over filling, which led to oil foaming. I routinely put over 200k miles on cars and I've never changed oil at less than 6k miles. My current engine has about 110k miles on it and is running SWEET. I change oil and filter between 6 and 8k miles. Once again though: I have no scientific reasoning for this. It just works for me.

 

The best we can do is gather the experience and comments of the forum members et al and try to determine what the evidence tell us is the "best practice"...there is no definitive right or wrong.
But, it is incumbent upon all of us to check our facts before we categorically dismiss any diagnostic tool (i.e. oil color) and publish it on this forum.

 

As you're relatively new here, please understand that the subject of oil intervals has already been thrashed to death countless times, and not once has anyone found any proof that the OEM intervals are inappropriate. So, 'we' in fact have done our research as suggested above.

I looked at your previous posts regarding oil changes and found NO examples to back up your claim that an abbreviated interval is required or of benefit. I did see an erroneous assumption on your part where and association of chain tensioner failure with oil type or change interval was made.

Using oil colour as an indication of appropriate oil change interval is about as accurate as Granny reading tea leaves in a cup. It's not the 1950s any more. A cursory search on the subject will reveal that oil darkening is a normal function, a sign that the additives are doing their job.

But- if you'd like to beat the horse again, I suggest heading over to the BITOG site. This is right up their alley.

 

Thank you Mikey...I can see you're a real gentleman, as you look down upon us "relatively new" guys. How dare we possibly challenge the Canadian guru with his six thousand posts!
Now, I'm finished beating the dead horse.

 

No need to get your shorts in a knot. If you've got some relevant info today or find some in the future, please share.