So i think im going to make the switch to rotella 15w40, becuase i've heard so many good things about it. I have been running Penzoil 10w30 high mileage for the last 1500 miles and i havent been pleased. Is anyone running Rotella? Do i have to flush my system before i make the change? Or can i just drain the oil and make a direct switch? Thanks. My 96 cherokee has 167000 miles on it.

nothing special, just regular oil change..

Why are you not pleased with the 10w30 HM?

I don't think you actually need something that heavy but I will say I bet you'll see some cooler operating temperatures. I use the Valvolines equivalent in my 500hp turbo 4cyl. but that's a different story obviously. I don't see why you NEED to go to it. If you're wanting something heavier just use a 40 weight. Regionally, where are you located?

Well ever since i started using it ive heard an extremly slight lifter tap at start up. Its not a problem but i just dont like it. lol

Unles you're putting it in a newly rebuilt motor that hasn't been run yet....save your money.

Rotella (or better still, Chevron Delo400) has alot of zinc in it. Great for preventing cam failures but no practical benifit to a motor that's already been run and is broken in.

Im located in North East Georgia. And ive also heard that this oil still has the proper amount of Zinc in it becuase diesel oil isnt regulated as much by the EPA or somthing like that. And of course zinc prevents the breakdown of oil, so you get the proper protection.

Ive actually heard that its very good on 4.0s with high mileage. what would you recommend running?

I would decrease your initial # go to a 5w-30 or 40, or even a 0w-30 or 40. That is going to provide your internals the oil they need quicker then 10w and definitely quicker then 15w and reduce or eliminate that tick. Everyone has there opinions or preference so go with what you would like but that initial # is very important when it comes to internal wear @ start-up (where the majority of wear happens) the higher visco you go the thicker the oil is @ crank and longer it will take to flow to all parts and lubricate.

Whats a good 5w40 out there? Im not sold on the 0's ive heard that they break down quicker.

Are u sure all those good things u've heard are about the 15w40......and not the 5W40?????????

Positive i actually read about them on this exact same forum

I use Valvoline 5w-30.

All Synthetics
Mobil1 0w-40 European, T6 5-40, Royal Purple 5w-30 or 0w-40, Valvoline SynPower 5w-30

These are great choices year round but these are really just my preferences in oil. I always try to stick with a brand and just stock up when it goes on sale as the DIY Oil Change Special.

Ok......if you're positive......'cause the 15W40 is plain ol' thick conventional motor oil, while the 5W40 is synthetic.

Rotella 15W40 is not plain 'ol gas burner oil.

It is a diesel motor oil with a high zinc content. The EPA mandated the removal of zinc from gas engine oils years ago but it is still available in some diesel motor oils.