Regular oil over synthetic oil

[satboyz]

What is the advantage of using synthetic oil? I have two gas motorhomes I rent one out and use regular oil and change the oil every 3,500 miles and the oil gets changed every month to three weeks. If I use synthetic oil, when should the oil be changed, or is there no advantage in using synthetic oil?

[wolfe10]

What is the advantage of using synthetic oil? I have two gas motorhomes I rent one out and use regular oil and change the oil every 3,500 miles and the oil gets changed every month to three weeks. If I use synthetic oil, when should the oil be changed, or is there no advantage in using synthetic oil?

What is the recommended oil change interval per your chassis Owners Manual?

I would suspect that using a synthetic oil (of viscosity recommended by your engine manufacturer) you should be able to cut oil change interval in half (so somewhere around 6-7000 miles/6 months.

BTW, I use synthetic oils in all my gasoline engines, but not the diesels.

Brett Wolfe

[NWJeeper]

What is the advantage of using synthetic oil? I have two gas motorhomes I rent one out and use regular oil and change the oil every 3,500 miles and the oil gets changed every month to three weeks. If I use synthetic oil, when should the oil be changed, or is there no advantage in using synthetic oil?

Many RV owners who only use their coach on a limited basis will change their oil based on time rather than mileage (like once or twice a year). For this reason synthetic oils would be just a waste of money over a good regular oil. For vehicles that get driven all the time, synthetics are a good way to go.

[jmonroe]

NWJeeper, I'd respectfully disagree.

I use synthetic for a number of reasons. One, it does seem to give me a slight increase in mileage. In my case about a .5mpg increase (I typically got 6 to 6.5, changing to synthetic increased mileage to 6.5 to 7). Second, it is my belief that the synthetic will "cling" to the critical parts better than a conventional oil, giving me better protection during engine start and better corrosion protection during long periods of storage. Maybe not so critical in my daily driver, but in a vehicle that can go weeks to months between trips...

Like most, I pull a 'toad' behind when travelling. While the combined weight of our rig is within limits, the engine will still get very warm/hot when in the mountains, or pulling into strong head winds. The synthetics offer far superior longevity and protection under these conditions and are not likely to turn to 'sludge'. I see it as some additional insurance.

The time limits recommended, as an alternative to mileage limit recommendations, I've always taken with a grain of salt. If you commute only 10 miles to work and back, especially here near the arctic circle ( ), the engine never gets to full operating tempurature and is continually building up moisture and other contaminants. In that scenario I'd agree with a time limit. Few of us use our motor homes for short commutes, however. If run at least 15 - 20 minutes past reaching full operating temp (this can be up to an hour total around here in the winter) any built up condensation or combustion contaminantes will have evaporated out. Eventually even a synthetic will wear out and/or acumulate potentially harmful contanimates, however, so nothing lasts forever! I do go 15k between changes on my daily driver though. I've got a 45 mile, one way all freeway speeds, commute every work day.

[NWJeeper]

NWJeeper, I'd respectfully disagree.

I use synthetic for a number of reasons. One, it does seem to give me a slight increase in mileage. In my case about a .5mpg increase (I typically got 6 to 6.5, changing to synthetic increased mileage to 6.5 to 7). Second, it is my belief that the synthetic will "cling" to the critical parts better than a conventional oil, giving me better protection during engine start and better corrosion protection during long periods of storage. Maybe not so critical in my daily driver, but in a vehicle that can go weeks to months between trips...

Are you using actual scientific results here or just your feelings? Perhaps there may be a slight increase in mileage but that is hard to quantify based on the fact that no one ever drives the same streach of road with their RV under the same conditions on a repeated basis to be able to say for sure. If you want your oil to "stick" to internal components then add a quart of Lucas Oil Modifier to regular oil, this stuff causes oil to stick like crazy.

Beyond that consider that most manufacturers call for oil changes from between 5000 and 7000miles or 3500 miles if driven in harsh conditions or extended towing. Now consider that most RV owners will struggle to put 3500 miles on an RV in a year and you can see why it becomes a "once a year" maintenance item, rather than a mileage based one. A good quality oil is not going to go to pieces on you in 3500 miles. In this case you could change your oil twice a year which would equate to a mileage of between 1500 and 2000 miles per oil change for the same price as doing it once with synthetic. However to me thats a lot of extra money spent for synthetic for no real advantage and would actually be overkill for no aparent reason.

However if if makes you feel better than do it. I just don't see the "economics" in it. If I were driving my rig 10 to 12K a year then I most surely would.

I will agree to disagree with you on this one...

Cheers...

[phylandmac]

To Wolfe10, why would you not use synthetic oil in your diesel ?

[wolfe10]

To Wolfe10, why would you not use synthetic oil in your diesel ?

With annual oil changes (based on time, not miles) it is not cost effective.

And the well-known diesel motor oils like Chevron Delo 400 and Shell Rotella T have proved millions of miles of trouble-free service in these engines.

I am not against using them in a diesel, just don't find them cost effective for the number of miles we drive between changes.

Brett

[smokeater75]

My wife Susan and I have made the round trip from Winnipeg to Palm Springs California 5 times in our SUV twice with regular oil and three times with synthetic. I averaged about 75 mph. and travel the same road there and back. I got 1.5 mpg. better with the synthetic oil. I have synthetic in all of my vehicles and the cold starting in -35 is not even close. When we purchase our 1st. motorhome this past August, I talked with a Cummins mechanic here in Winnipeg. He told me that starting a diesel in -35 was like driving it a 1000 miles as far as wear was concerned. He felt that in those conditions tha synthetic was offering more protection. That was good enought for me and I proceeded to change all the fluids in our coach to synthetic. I'm not saying that synthetic is for everyone but until we can head south for the whole winter, it will be in our coach. Smokeater 75

[wolfe10]

My wife Susan and I have made the round trip from Winnipeg to Palm Springs California 5 times in our SUV twice with regular oil and three times with synthetic. I averaged about 75 mph. and travel the same road there and back. I got 1.5 mpg. better with the synthetic oil. I have synthetic in all of my vehicles and the cold starting in -35 is not even close. When we purchase our 1st. motorhome this past August, I talked with a Cummins mechanic here in Winnipeg. He told me that starting a diesel in -35 was like driving it a 1000 miles as far as wear was concerned. He felt that in those conditions tha synthetic was offering more protection. That was good enought for me and I proceeded to change all the fluids in our coach to synthetic. I'm not saying that synthetic is for everyone but until we can head south for the whole winter, it will be in our coach. Smokeater 75

I agree. Starting in extreme cold is an excellent reason for going synthetic.

Brett