May I ask, why in the world would her recomend it to me for my beat up old I6 then?!

 

He explained exactly why. He works in oil research so I have no reason to doubt him.

 

I see, Does not really seem worth the money to me though..

 

Why not just stick with what has worked for 241,xxx miles? I think sometimes people over analyze what do as far as brands of oil.

 

I just found out last night that the guy I bought the truck from always used a conventional 10-w40 year round. I think I'm just going to keep giving the old dog the same food.
It's and inline six it will run even without oil right

 

Damn right it will. Have you seen the youtue videos of dealerships "clunker bombing" the inline six? It hurts me to watch, but those things lasted a lonnnnng time before they finally gave in. That is a great motor. Just change the oil with in the normal intervals and I'd think you'll be fine.

 

i love my ol inline 6 241,800 miles and no ticks, weird noises and uses no oil between changes

 

Russo, sorry I didn't get back to this thread. The Rotella named oils are known as dual rated oils. They are rated for diesel and gas engines, not diesel alone. You'll find the base oils to be a lot more robust than any conventional oil rated at SL or SM which makes them ideal for your application. If you're uncomfortable in using the 5w-40 oil, there is also a straight 30 oil in Rotella. I would not suggest using any conventional 10w-40 oil. The difference is the base materials used in getting the viscosity spread. The 10w-40 will be loaded with polymers- the same crap that makes for a lot of sludge. The 5w-40 makes the spread via Viscosity Index and requires very little VIIs in the formulation.

You also find Chevron Delo 400 and Mobil Delvac to be dual rated oils so if you have preference, pick one. But most of the high performance guys are using Rotella due to the ZDDP (zinc) content in the formulation. While rated as an API SM oil, it exceeds the limits set by API for the SM rating. It tops the limits for SL as well. FWIW, your engine requirements when new as SG rated oils which had almost twice the ZDDP as the current SM oils. ZDDP is an anti-oxidant, friction modifier, anti-wear, extreme pressure, and metal deactivating agent. For the most part, it became popular in the 1950's as a cure all for engine wear. Engines from those days only lasted about 50,000 miles, some of the wear due in part by the leaded gas of the day. As we grew in technology to unleaded fuels, engine life has increased. But the older engines designed to use this agent in the oil formulation will suffer accelerated wear usually at the cam and lifters. Solid and flat tappet lifters are gone as a result- rollers are in. This an extremely abbreviated version of why I recommended the Rotella. I hope it helps you determine what is best for your truck.

 

Royal Purple THE END!

 

Labnerd brings up a good point re: 10w40, but there's also the "if it ain't broke, don't fix it" factor.

Re: Royal Purple - I'd be a bit hesitant about putting that into an engine that's been run a quarter of a million miles on conventional 10w40.

 

Thank you much labnerd, when I build up my new inline six i'm definitely going for this rotella or something like it.
Royal purple is a no it will probably clog that engine tighter than a bear in january.
Thank you to all that have helped though

 

OP- if it were me, I would put the same oil in it that you have always put in it.

 

I just bought the truck and I just wanted some opinions on what would be better but I'm sticking with 10-40 conventional like what has been used in it since day one.

 

I agree wholeheartedly with the recommendation about Rotella oil! I have a '99 4.2 with a 4R70W automatic with about 260,000 miles on it that I bought used a little over two years ago. The original owners (a company) had all their service receipts from new, and they had always put Rotella T 10W30. I have continued with this. The engine uses NO oil between changes, runs like a top (except for an annoying ignition problem that I have now solved), and just towed a 4,200 lb. travel trailer 2,000+ miles on a vacation trip to Key West. It maintained 65 mph on Interstates (except up hills!), and never overheated with outside temps in the high 90s and the a/c running. The oil level has not changed from where it was before I started the trip.

If the engine in your truck has NOT been using synthetics, do not start using them! They are much more likely to leak past old seals. All oils pass a seal compatability test, but leaks can occur in older engines that have seals which are varnished over from the inside and have become dried out. High detergent levels in synthetic oil can clear away the "false seals" and allow leakage. It can also lead to excessive blow-by and premature oil contamination because the detergents can clean deposits from the piston rings that are helping maintain compression.

Stick with conventional oil on your high-mileage engine, and as far as I'm concerned, Rotella T Triple Protection 10W30 is the way to go.