I bought my truck about a year ago and it runs great, but I'm not absolutely sure how well it was maintained by the previous owners. I have been entertaining the thought of switching to the pseudosynthetic Rotella, but I didn't know if it was too late to make the switch. It is nearing 200K miles and I was reading that if over 115K, it was best to stick with dino (regular Rotella) if the change wasn't made yet. I guess it has something to do with the synthetic loosening up too much gunk. Is this all true, or is it ok to make the switch? Thanks in advance for all of the help.

 

You are definitely taking a chance at 200k, I personally wouldn't do it.
Synthetic has a solvent effect that could wash away sludge that is presently blocking leaks.

If it's any consequence all of the million mile plus CTDs I've read of were run on dino oil.
What more do you want?

 

Kind of a depressing thought that maybe an engine is being held together with sludge.

I don't know what is so magical about 115,000 miles, or 200,000 miles as a turning point.

You can probably get another 200,000 miles out of it using dino, so is that enough? Is synthetic going to give you more than that and be worth the cost?

I've decided to stick with Delo 400. 110,000 and counting.


John

 

Good point guys! Dino works in the big rigs, so it should be sufficient in the little Cummins. I'll take the money saved and put it in the torque converter fund. Thanks for the perspective.

 

I switched mine over to syn at 90k. I change my oil every spring, yes that is right once a year. Even on the Cummins website for the ISB6 they recommend 15k on dino oil. Everything at my house that takes any kind of lube gets Amsoil.

 

If it ain't broke...don't fix it...

Seriously, I tried Rotella Synthetic 5w-40 on mine this summer, (yes with 330k) and the results were not ... positive. on me.

It's back to 15W-40 and happy with it.

 

I do the same every July 1st, Drain and replace with amsoil 15w40 heavy duty full synthetic diesel oil with a donaldson nano tech filter. I dont think I would bother to use it in an engine with 200k this gunk that synthetic loosens has probably already caused the wear that the synthetic would allegedly prevent. Even Amsoil comments on this leakage with hi milage engines. Another comment I have on Cummins engines with only 200k on them is; this is not a hi milage engine, it's a proven reliable engine.

By the way, this oil I drain every July looks so clean that I cant bring myself to throw it away soooooo I use it in an older madel ford 351 windsor gasser I have. Hasn't caused it to leak---yet.

 

I love synthetic oils.

But dino oils keep getting better and better, and the justification for going to a synthetic is an increasingly tougher to sell.

Cold weather used to be a strong selling point of synthetics, but even dino 15w40s are down to -40 as a pour point now.

I'm starting to think that additive package matters as much or more than than the base stock an oil starts with.

If you mod a Cummins, you'll soot up the oil much faster and you can't really extend the drains to take the edge off the cost of synthetic.

As for all the million mile trucks using Dino-- I don't take that to mean that dino is better-- just that's it's proven to be more than adequate. Would the same truck last longer with synthetic? Possibly, but we'll never know.

The million-mile trucks aren't all that impressive to me, because these engines are running almost continuously-- very few cold starts, very little stop-and-go. One of those million-mile trucks ran Delvac and changed very 30K miles! 30K miles on dino! That's tells me the truck is rolling on the hwy all the time, which is about the easiest mileage a vehicle can accumulate. Towing increases average cylinder temp, which reduces bore wear and helps the engine last longer.

So I don't think you can find a name-brand oil that will NOT work well in these trucks, provided it's the proper viscosity. Better to go a little thicker than too thin on thes trucks, but that's jmo-- no proof.

JH

 

Why not try cleaning the engine out with Auto-RX or something?

I personally use a product called Lube Control which dissolved sludge and varnish inside the engine and let it drain out at oil change. Oil got black fast as it went to work cleaning things out. This was on a Nissan with 150K miles on it. No leakage problems at all.

I like the Lube control because it cleans things slowly-- that sludge and varnish doesn't get their overnight, and trying to remove it instantly with a strong product is one reason I think leaks appear when efforts are made to clean the inside of the engine.

www.lubecontrol.com

*no affiliation with lube control*

jh

 

I just checked out the lube control website and it seems very interesting. Since I probably won't switch to synthetic, would it be good to use the lube control anyway? I am into anything that can help the ol' girl feel young again

 

I like the Rotella 5-40 synthetic for the slight increase in fuel economy and the easier cranking/faster starting in cold weather. If it also happens to make the engine last longer...that would be nice too. But, with a service life of half a million miles, I'll probably never find out if the synthetic would have made it last longer.

 

I had syn in mine. Now I have a Frantz oil cleaner and I run Dino. I was not impressed with the syn oil.

 

I used it on my Nissan with dino-- worked very well. Engine ran "freer" and all the varnish that was built up on the dipstick disappeared, as well as all the varnish on the valvetrain.

The oil got REALLY black, but that's fine because it's cleaning all the junk out of the inside. I love the stuff.

I'd wait to do an oil change with dino, then dump in a fairly high dosage of the LC20, then change the oil early-- like 3K or so.

Then go with another dino change and go up to normal oil changes-- 5K or longer as you see fit. Just keep adding the "maintenance" dosage periodically. The info is on their site.

It smells like nothing else I've ever smelled-- very interesting, but keep it away from teens!

 

hi
bought my truck at 276,000 unknowen histery ? and a stp oil filter ???

279,000 changed oil and filter to 15-40 penzoil and napa filter for 1000 mi then

swiched to 5/40 rotella syn <walmart > and a fleetguard stratopore filter .

oil stayed clean for long time , still not real dirty at 281,000

no new leaks have ocured !

i have some seaping at the vac pump where it mounts but it leaked there before , i been puttin off replasing the gasket , lazy me !

i plan a once a year oil change !

i am pleased with it as a oil and price !

there has been no change in oil psi !

 

While we re on the subject, IV got an 05 with 35K on the clock.
Would it matter which brand syn oil was used as long as it was full syn to begin using syn and then switch to another brand like Amsoil?