I run 15w40 diesel oil and a mopar or motorcraft filter, here the temperature ranges between 0 in the winter and 95 in the summer and it does fine.

 

You can't fight success can you?

 

You would think so and that is how it should be but it doesn't work that way. An engine also does a certain amount of external "air cooling" also. Especially the oil pan. So temp extremes really do make a difference in how this extra cooling or lack of cooling affects the oil temp aside from the coolant temp.

 

I've been using the T6 stuff for a couple of years, in my '94, like since I found the thread on this....No problems of any sort have developed....
OAT here rarely gets over about 94 degrees....

 

Rotella T6 formulation and code was changed about a year ago. Maybe less.

Attn: Salad--Any thoughts on this?

 

So been doing some reading, am I correct in thinking I need an adapter to run a wix 51515 in my renix? Is so can someone point me in the right direction? I already have to do an adapter repair as my o-ring has failed and I'm leaking >10drips/min, maybe closer to 20

 

Very interesting unit of measurement haha

 

Hey it's all I got

 

I like using the Rotella T6 for several oil changes. It has good detergent and cleans the engine's internals very well.

Then I switch to Mobil 1 5-30. Smoother, quieter and better economy.

Here in PA- 0*F to 100*F, engines runs 210* and good oil pressure.

 

The Royal Purple isn't going to HARM your engine... it's just friggin' expensive as ****! lol.... don't drain it and change your oil now, just wait until your next oil change and go with something more affordable that performs just as well!

Did you read the data on the first page? I don't see how you could say "Any good brand of oil of the proper weight will be fine" if you actually read it. According to the data provided, certain brands of oil provide ZERO protection against wear. Others have lots of the elements that are supposed to protect against wear but have so many detergents, they don't have a chance to do their job. I'm not saying "go with Rotella", but even the brand of oil is not a "one size fits all".

 

Thats actually an airplane measurement criteria if you can believe it. Too many leaks per minute and the plane can't fly.

 

Whats the best oil/weight for cold weather?

 

^This, Royal Purple is good oil, it just isn't substantially better than any other decent synthetic oil, and can't justify its exorbitant pricing.


In any case it doesn't make much sense to put super "high-end" oils (AMSoil, Royal Purple, etc.) in an XJ, since the 4.0L I6 tends to contaminate oil (being a 50 year old design it isn't as "tight" as modern engines) limiting any extension of drain intervals. While the oil may be good enough to last 15-20K mi+, it will likely be too contaminated with fuel and combustion by-products by ~5K-10k mi and need changing anyhow.

 

Check that first page... all the goodies are right there in those first 10 posts.

Seriously, it's a lot of reading, but it's WELL worth it.

 

Hate to bring this up again... But why is everyone stuck on expensive high mileage synthetic oils when it really should be changed every 4-5k anyways? Consumerism?