Undertaker

Is there any advantage to running synthetic oil in my cummins opposed to dino oil?

nelrod

Not unless you put in a, Bypass system, do UOA's and run extended OCI's, that is my opinion. JD 15/40 plus 50 (as they call it) is a really good oil at a good price and is also CI. If you have 6.7L you need CJ. Ask this on Bobistheoilguy.com or research it and you will get some more info.

Fiftygrit

I like to use it as I tow lots and feel synthetic doesnt break down as fast when hot, I use it in my harley my quad everything.

.boB

Synthetics have two big advantages over dino:

1. they handle heat better. This is usually not a big problem. RPM's heat oil, and a diesel just doesn't see that many rpm's. With low rpm's, the oil tends to be about the same temp as the coolant, which is well below it's service limit.

2. Longevity. Synthetics easily last 50-100% longer than dino. If you don't drive it that much, and change the oil once a year, dino will do the same job for a lot less money.

A true synthetic oil starts with a PAO base stock, not dino oil. AFAIK there are only four true synthetic oils on the market: Amsoil, Royal Purple, and Redline. I can't remember the 4th one, but it's not Mobile 1. The rest are all modified dino oils. Not a bad thing, as long as you're not paying synthetic oil prices for them.

hector

I can't say that I completely agree...Synthetics provide superior wear protection over dino. Not to mention better flow & starts at lower temps. Longer drains are just an xtra benefit

SundayMoney

You're right...Mobile 1 isn't one of them.

Mobil 1 is though.

Schaeffer also makes Group IV oil.

ljutic ss

Also a big advantage of synthetic is it's ability to maintain viscosity in extreme temperature conditions such as saraha/artic weather.

DirtEater

Motul is also PAO(I know, it's French). I'm not so sure anymore that RP is a "true" synthetic though I have used it in the truck for 3 oil changes in the past. I switched to Mobil1 simply because it available in 1 gallon jugs, and easy to find in that size, and not overpriced like RP. Not sure really if one's better than the other, but the gallon jugs at wallyworld are a bonus.

Also use RP 10W40 in my '09 YZ250F, and their TCW3 in the 2 strokes, and their ATF in the 2 stroke trannies. Good stuff. But I'm not sure why they choose to make 15W40 their Diesel oil, rather than 5W40 like others.

Using RP for oil change costs $30 more than using Mobil1. Not sure why either. Amsoil and Redline are even more ridiculous!!!

hector

Qualty usually cost a little more.. The higher priced oils usually have higher quality ingredients

DirtEater

I agree somewhat. I don't mind paying more for quality most of the time. But there probably isn't anything that truly shows RP is a higher quality oil than Mobil1. It's merely a persons opinion of what is "best".

Like I said, I used RP for 3 changes. What really irks me about them is they raised their prices significantly when oil hit $147, yet they have still not lowered their prices now that oil is half of what it was. That's pure greed. Meanwhile, Mobil1, Rotella, Delo and others have lowered their prices by about 15-20% or so, since the barrel costs dropped.

DirtEater

Another company that quickly raised their prices when the barrel shot up, yet still hasn't lowered their prices now that the barrel is around $70, is Power Service. Before oil rose, you paid about $12 for a 96oz jug. Now, it's about $17 for an 80 oz jug. Did anyone notice they did that? That's right. In addition to raising their prices, they shaved their container size by 16ounces down to 80 oz jug. Pure greed!

Hvytrkmech

I run LE monolec 8800, 10k change, if my next UOA is like the last one I will go to 15k change and so on. 8800 is 100% paraffinic grp3 oil. It out performs almost all other oils, with the only exception being in arctic climate cold start flow rate.

Schaeffer also makes a great product.

DirtEater

I'd use Schaeffers again if I could find it locally. I used their 9000 series 5W40 for one oil change. Good oil, not outrageous like the "boutique" brands.

DirtEater

Also, I've never heard of the Monolec. I'll have to check them out.

Hvytrkmech

Lubrication Engineers, Monolec 8800.

Some interesting reading, here you go


http://www.le-inc.com/index.jsp