To go with synthetic oil?

It is that time of year where I always do the maintenance on me coach and I was leaning towards going with synthetic oil for my ISL 400 Cummins. I have 30.000 miles on it.  But I am wondering if any of you have had any experience with this? Just talked to a gentleman the other day that did it and had to rebuild his motor because of it. So do any of you have any input? Thank you

I've not used synthetic in a MH however, I have used it for years in just about every other kind of motor and I'll keep using it in everything I own.

If the specs are the same as the mfg. suggested oil, synthetics are definately a huge step up from dino oil.
JMHO

Harley Davidson Motor Co. use to claim that it was to slippery and would cause flat spots on the bearings because they wouldn't roll, just slide.  Come on now.....I was born at night but it wasn't last night.  Years later they finally came out with their own brand of syn oil and now they say it's OK.

Just talked to a gentleman the other day that did it and had to rebuild his motor because of it.

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Synthetic oils can loosen accumulated sludge in older engines and soften seals in engines built before around 1999. Your ISL is newer than that and has seals & gaskets designed with modern oils in mind. I would not be concerned about that aspect.


Synthetic is good, but I prefer to change my engine oil annually, so it's not really cost effective for me. Would hate to throw away 28 qts of expensive synthetic oil every year, but cannot get comfortable with letting dirty oil sit in the crankcase for more than 12 months. I think a good quality dino oil, changed annually, is fine for an RV engine (I use Shell Rotella 15W40).

I do use synthetic in my tranny and rear axle, and I extend the change interval on both of those, using fluid analysis to verify the tranny fluid is still good. Perhaps it makes no sense that I am willing to do that on the tranny, but not do the same for the engine oil, but the engine oil accumulates soot and acids, even though it is still ok as a lubricant.

In my opinion, the large quantity of oil that a modern diesel engine requires doesn't justify the much greater cost of synthetic.  I don't believe that synthetic oil would extend the change interval either, so there is no advantage to using it.  Change oil according to the manufacturer's schedule, use a good grade of regular oil, and you'll be money ahead.  But I know of no problems caused by using synthetic as long as you keep to the normal maintenance schedule.

Like Gary, I have synthetic in my transmission and differential, but those do extend the change interval so are cost effective.

Thank you for the replies. Ned and Gary, thank you for all the information that you share almost daily it seems. The reason I was considering going with the synthetic oil is a new distributor that cares Shaffer oil just opened up close to home. I can buy 15-40 Rotello for about $16.00 per gallon and the Shaffer saleman will sell me the synthetic for $19.00 per gallon. I think that is a good price? Plus he told me all the selling points of it. The big point was the increase in milage that is picked up supposedly? He stated that it is about 9% for the trucking community.Oh well, I told him would consider it. Thanks again.

I agree with what others have said.  I would add the real benefit of synthetic oil is for those who live in or frequently travel in colder climates.  This is because synthetic oils do not thicken up like dino and begin to lubricate the internals much quicker.  Other than that, I do not see the benefit of synthetic.

Plus he told me all the selling points of it. The big point was the increase in milage that is picked up supposedly? He stated that it is about 9% for the trucking community

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I'd want to talk to that trucking company, because that sounds a bit far fetched in my opinion.  My mechanic has told me that he runs synthetic in all his vehiclals including his motorhome because the change interval goes from anually to every 10,000 miles.  But other than from some foum "experts" on other forums I cant find any literature to back that up.  The guy at Workhorse that I talked to actually laughed when I asked that question, and told me that is an oldie but goodie of a whopper.  He said if you want to spend the money go ahead but follow the change intervals in the book.  If they dont specifically say the change interval is extended using syn oil, then it isn't.  So I use it in the tranny, because the book says it gives me an increased change interval, but normal oil in the engine, because the book doesn't say so.

Jeff

Terry,
  I have been using Shaffer oil for several years because a friend started being a representative for Shaffer. I think for the price that would be their synthetic blend and not a pure syn. I have been completely happy with the oil in everything from race motors to farm tractors but it isn't anything better than a good quality oil just like the other major brands I've tried. I agree that dino oil or synthetic both have valid uses and benefits just don't buy into the sales hype. I'm getting a bit more cynical as I age. I've just bought one too many bottles of snake oil. 

Synthetic has some definite benefits if you live in a very cold climate.  It doesn't thicken quite as much in really cold weather (below 0F), which means your engine gets oil through those tight tolerance areas quicker.  Synthetic also has a longer duty cycle, allowing you to go longer between oil changes. 

Unfotunately, it picks up particulates at exactly the same rate as dino oil.  So you can keep the oil longer, but you have to keep swapping filters to keep that oil clean enough to avoid problems.

The long and short of it is that dino oil is good enough. 

Heat guys.....heat is where synthetic makes it worth it.  If you're traveling in high temp regions (or live in them) or traveling mountains a lot.....it's the heat issues where syn makes it worth it.

Do the research...it's documented.  What's the boiling point of dino oil?  What's the boiling point of syn?

Air cooled motors, Harleys....rode em all my life.  I've tore down more motors than I can remember.  Take a Harley that's run 60k-80k miles on dino oil and open that motor up and look at the flywheels, bearings, cylinders, pistons, rings.  Take a Harley that's run 60k-80k on syn oil.......it'll make a believer out of you. 

If you plan on keeping that vehicle and putting the miles on it, working it.....syn will pay for itself in the long run.

There's a lot of documented research regarding the two available now days....do the research, don't take anybody's word for it....it might be snake oil.

Here's a number of websites that you can read then decide for yourself.  Here's some info. (from some of those companies that produce dino oil) to help you get started on the research....

http://auto.howstuffworks.com/synthetic-conventional-motor-oil.htm

http://www.jdpower.com/content/detail.htm?jdpaArticleId=208

http://www.google.com/url?sa=t&rct=j&q=petroleum%20oil%20vs%20synthetic%20oil&source=web&cd=3&cad=rja&ved=0CFIQFjAC&url=http%3A%2F%2Fwww.articlecity.com%2Farticles%2Fauto_and_trucks%2Farticle_1304.shtml&ei=gy-6UKvhJOjoiwLBq4C4Cw&usg=AFQjCNHimQRNRVbukeFLahWj9UcRTw_pcA

http://www.mobiloil.com/USA-English/MotorOil/Synthetics/What_Is_Synthetic_Motor_Oil.aspx

http://www.thelubepage.com/learn/lube-notes/lube-notes-synthetic-versus-petroleum-oil

http://www.machinerylubrication.com/Read/23715/conventional-vs-synthetic-oil

http://www.minitruckinweb.com/tech/engine/0901mt_conventional_petroleum_oil_vs_synthetic_oil/viewall.html

And regarding that claim of increased mileage, I just found this.....  http://www.amsoil.com/performancetests/G2904.pdf

The trucking/oil company that I worked for switched to synthetic oil a number of years ago. I have only anecdotal information but our results were not anything to get excited about. In the year and a few months that we used it we had a dramatic increase in failed engines, some catastrophic. I can't blame the synthetic for the failures but it was interesting to note that prior to that we did on average one in-frame per year out of 35 trucks.

Remember that corporations feel (rightly so) that a static growth record is a bad thing, new and improved sells whether or not it's new or improved, synthetic oils are another way of generating additional sales in my opinion.

By the way, anybody got any idea what they make synthetic oil out of?? It's OIL!! It's not made from tree bark or toenail clippings or wheat chaff, it's made from oil in petro-chem plants just like good old Pennsoil. Sorry but it just drives me a little nuts when big companies play fast and lose with terminology while trying to entice us to spend more money on things that we might or might not need. Regular old oil has worked since the days of the steam engine and worked quite well in my opinion, I'll keep using that old fashioned lubricant so I can afford to spend my money on other more important things like seeing all that I can see before they plant me.

Our synthetic tests in the industrial world were typical of Joes, nothing to actually measure. There are other, far too many variables that make more difference IMO.
I will swear by synthetic for air cooled engines as that is where the synthetic or blend really shines. The synth has such a higher temp limit it will pay for itself in short order, especially on motorcycles as JCZ has said above.
The best I have found for my Cat and other diesels like ours (on the road) is 15 40 Shell Rotella T as others are using. It is easily found at any Walmart and goes for app. $13/gallon. JM2C

By the way, anybody got any idea what they make synthetic oil out of?? It's OIL!!

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Certainly true for the vast majority of synthetic oils on the market today, though they could be made from other, non-petroleum, base stocks if needed. The key thing about synthetics is that they are engineered oils, made to have consistent types and lengths of molecules for maximum effectiveness at their job: lubrication and cooling across a wide range of operating conditions.

I guess I'm just a skeptic when a company is trying to sell me "New & Improved" and I have a hard time switching off of something that has worked well for so many years.  Having worked in the transportation industry for the last decade or so has given me a few insights into just how long the typical diesel engine can actually function and function well.  When I started off my driving career I worked for a municiple transit system, we had two dozen bus conversions that used the PowerStroke 7.3 engine. Although everything on the bus except the steering wheel had a tendency to fall off or break, those engines were bulletproof and were fed a steady diet of petroleum based Shell Rotella. Most had in excess of 750,000 miles of Arizona city driving on them before they were taken out of service, that's a pot load of miles on an itty bitty engine driving a heavy bus chassis around in very EXTREME temperatures five months out of the year, not to mention the very long idle times they experienced.

Then of course you have the Class 8 trucks like I now drive that can easily hit the million mile mark running old fashioned motor oil, I just don't see the "need" for the fancy stuff. Our Freightliner FL50 is powered by a Cat 3126 (250hp) and has to date logged just over 350k, I'd be paranoid in the extreme to attempt to change that old girl over to synthetic simply because she might just die from shock.

On modern motorcycles I can see how it might not be such a bad thing but here again, I've put north of 100k on a half dozen bikes in my 38 years in the seat all on the old fashioned oils so I just can't justify it.

You don't have to convince me, Joe. I use Rotella in my 8.9L diesel and change every year. I like synthetic in the tranny and rear end, though. Primarily for its resistance to heat plus I don't change those often anyway. I have almost 9 years on the synthetic tranny fluid and it still tests out as fine for continued use.

Personally I'm another not sold on the synthetics either. When I see more Cummins diesel trucks crossing the million mile mark with petroleum based oil than synthetics it tends to say a lot about the petroleum oils. 

hes4all said:

It is that time of year where I always do the maintenance on me coach and I was leaning towards going with synthetic oil for my ISL 400 Cummins. I have 30.000 miles on it.  But I am wondering if any of you have had any experience with this? Just talked to a gentleman the other day that did it and had to rebuild his motor because of it. So do any of you have any input? Thank you

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First off if you believe the guy you just talked to about this change what else do you want to hear?

So think of it this way, most no one here or even most any shops will not know what is better for your engine than Cummins! The amount of testing done by them and for them is an unreal amount, (I know this from working in research of a major oil company for 20 some years) use just what they re comend for their engine design! That oil will also be available just about any where you may be also when it is needed. JMHO

JCZ said:

Heat guys.....heat is where synthetic makes it worth it.  If you're traveling in high temp regions (or live in them) or traveling mountains a lot.....it's the heat issues where syn makes it worth it.

Do the research...it's documented.  What's the boiling point of dino oil?  What's the boiling point of syn?

Air cooled motors, Harleys....rode em all my life.  I've tore down more motors than I can remember.  Take a Harley that's run 60k-80k miles on dino oil and open that motor up and look at the flywheels, bearings, cylinders, pistons, rings.  Take a Harley that's run 60k-80k on syn oil.......it'll make a believer out of you. 

If you plan on keeping that vehicle and putting the miles on it, working it.....syn will pay for itself in the long run.

There's a lot of documented research regarding the two available now days....do the research, don't take anybody's word for it....it might be snake oil.

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Um, the oil in your engine doesn't get any hotter when it's 120 degrees outside than it does when it's 85 degrees.  Internal engine temperature is determined by how your coolant system is set up.  If your thermostat opens any time the coolant goes over 180 degrees, outside temperature is irrelevant unless you overload the cooling system.

You will never reach breakdown temp on either dino or synthetic.  Not unless your engine is about to grenade because you ran the coolant out of it, that is.