Synthetic oil or not?

[Journey32]

I bought a 32t Winnebago last Sept. with the 275 hp cummins. Does someone out there have any advise on whether I should go with synthetic gp IV oil or not? Also what kind of mileage or time frame between oil changes? Tnx, Gene

[John-D]

I have read a lot of posts talking about Synthetic and regular oil and frankly

I'm convinced of the benefit.

Now: Should you go with it? Can not say. But if your engine is in good condition (no more than 1-2 quarts addced between oil changes) It might just be worth it.

However be aware that not all synthetics are created equal. I have come across a study ranking several different brands and it mentioned that some brands were, for example, better for Indy Style racing, and others for Whorkhorse type jobs (as it turns out my local Workhorse Authorized Service Center uses a synthetic that came out very well for the type of service I use it for)

I was surprised by some of the ratings though.

[KIX]

I don't think the cost/benefit is "there" for diesel RV engines. The reason I say that is because the very popular ISC Cummins requires oil chage at 15,000 miles or 6 months. Most RV's are not driven anywhere near that mileage in the alloted time. I do think synthetics are more appropriate in an RV in the differential, hubs and transmission. Of course, your mileage may vary.

[oldvectra]

Cummins says synthetic oil is not necessary and for most rv diesel engines it doesn't make much sense to spend the extra money on 5 - 6 gallons of oil synthetic oil. I
believe Cummins recommends 15,000 miles or 1 year for my ISC and I might get 6000 miles in a year. So if I use synth oil I still have to change it after the 1 year. Cummins also states that using synth does not increase the oil change interval.

[GaryKD]

Hi Gene,
I've never used synthetic oil. Dino oil has performed perfectly for me for over 44 years. Consider putting in the correct Dino oil and change it according to the manufacturer's recommendation.

When an engine comes with synthetic oil and the manufacturer recommends continuing with it, then I'll change my thinking too.

[read & learn]

I have used synthetic in my cars for years only because I can go 7,000 miles between oil changes. I know a lot of MFGs say you can go that far on regular oil, but how and when did oil get that much better.
Would I use it in the Motor Home the anwser is no at this time.
I have been watching a freind who has switched to Amsoil with a by-pass filter system and has not change his oil in 3 years. Every 6 months he takes a sample of the oil, ships it a lab and than gets the results telling him what has to be done to maintain the oil at it current level and or if it will need to be totally replaced. The flters also have to be replaced on a regular schedule.

[The Danes Are Coming]

Quote:

Originally Posted by oldvectra Cummins says synthetic oil is not necessary and for most rv diesel engines it doesn't make much sense to spend the extra money on 5 - 6 gallons of oil synthetic oil.

When we were given "the grand tour" of a Cummins facility in Oregon, this is exactly what they told us. They say if you stick to the recommended intervals for the oil change, then they recommend the use of standard oil.

[raycon9]

I have been using synthetics for years and have no "proof" of anything.

there is nothing wrong with the dino oil at mfg intervals.

But, with "Real" syn like Mobil1, Redline or AMS. i think the engines will last a little longer, run a little smoother, be cleaner inside, perform better at high temps and less change in viscosity with use.

i would not spend my money on the other syn's.

JMO

[Journey32]

This has been my first experience with iRV2 and I want to thank you all for your responses. They have been helpful--many different opinions and that's what we need to be able to make our decisions. Tnx, Gene

[EngineerMike]

I started using full synthetic in a motorhome w/25,000 miles on it. Seals started weeping, and I found others had the same experience. I changed back & the weeping dried up, the same as was reported by others. This was with a GM 6.5 diesel. The Delo 400 recommended for the engine worked great thereafter. And like most here, I never did the bruising volume of miles that professional truckers accumulate, and will never get close to a major overhaul on my current rig. I'll stick to dino oil.
The Allison came w/Transyn, and I'll stick w/that so there are no flushing issues.

[Sixpack98]

I just don't see the value of running synthetic in a diesel. I run synthetic in my wifes car because the manufacturer covers the first 60k miles of service and synthetic is what they use. Since Cummins says dino is what they recommend that is what I use.