Synthetic Oil vs "Dino" Oil

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.

Fizzban

Well-known member
Joined
Jul 31, 2006
Posts
60
Location
Memphis
I have been researching Synthetic oil....The reason, is my wife was told that the last time she had an oil change the receipt said they used Synthetic, and the oil guy said she shouldn't because the seals have been used to regular oil for the 60K miles she has had the car.  He said that using Synthetic would cause the seals to leak.

I found some reference to this, but most say that synthetic should be used anyway because the synthetic will still give more protection to the engine.  This is true because not only is it a better lubricant, but that it coats the pistons all the time so you get no wear (or less wear) upon start up.  It also works better at high temps that you may get when the engine is under strain.  Reports of better gas mileage and higher power also surface.

I have on vehicle with 60K miles, another with 85k miles and another with 110k miles...I am thinking about changing all of them.  Some say you should, but do engine flushes first in order to get all "contaminated" regular oil out of the car, others say the idea of a engine flush is bunk because on older engines, the deposits in the engine may just be solving problems and you should leave them there. 

Does anyone know what is really true?  Also it appears that Amsoil, and Mobile 1 are the preferred choices.  Your thoughts are appreciated!

THANKS
 

jamesnaddie

Active member
Joined
Aug 9, 2006
Posts
41
Location
College Station, TX
Have a look at Royal Purple oils.  We use their products in everything we build or use.  Changing to their gear oil lowered operating temperatures in planetary gearboxes by 20 degrees.  www.royalpurple.com  is their website and NAPA stores here in TX carry the products.  I switched to Royal Purple synthetic years ago in a 1997 Tahoe with 56,000 miles.  No problems and about a .5 MPG increase in average milage over the next 40,000 miles.  I run it in everything I own even the lawn tractor and next oil change it will go into my new Foretravel Nimbus.
 

John From Detroit

Well-known member
Joined
Apr 12, 2005
Posts
25,231
Location
Davison Michigan
There are a lot of folks who are spreading myths about synthetic oils "Oh you should not use synthetic because__________"

Well let me run down a few fill ins for that blank

It costs more:  This, is the ONLY true item on the list, THE ONLY ONE

You can not mix them:  Ever hear of Durablend (Synthetic an dino mixed)

You cant change back, (See last comment) this is pure bull

Seals may have absorbed the othe rkind: So, see previous comments, they can be mixed

It is thinner, sure, at zero degrees, thus providing superior lubrication

It's thicker, Sure at 200 degrees, thus providing superior lubrication

And as for the cost, well, that is short term, long term since it provides superior lubrication your engine lasts longer and thus it costs LESS over all.

Oh yes, Top end synthetics can last longer between oil changes

So when a man who makes his living fixing or replacing engines that have worn out early due to poor lubrication tells me not to use Synthetic.... I tend to ignore him.  Likewsie when a man who makes his living changing oil tells me not to use synthetics I tend not to listen.  After all, If I use longer lasting oils, they loose business, lots of business.
 

Ron

Moderator Emeritus
Joined
Jan 29, 2005
Posts
18,082
Location
Home is where we park it
I am a firm believer in Synthetic oil.  We have used Amsoil since around 1974.  It is my firm conviction that Amsoil is the very best synthetic available for automotive use.  My second choice would be Mobil One and I would go back to Dino oil before I would ever use a Castrol product.  As for synthetic oils damaging seals that is hogwash and I sure wouldn't let the guy that said that ever touch any vehicle I own.
 

Gary RV_Wizard

Site Team
Joined
Feb 2, 2005
Posts
74,619
Location
At our Silver Springs FL home
Synthetic oil is outstanding stuff and, as John says, the "you can't..." stuff is mostly bunk. However, I would question the economics of putting expensive synthetics in an old engine.  Even the best oil won't reverse the efects of 100,000 miles of wear, so you may as well continue with the less expensive dino oil on them.

It is true that synthetic may leak around old seals. It's not because the seals are acclimated to dino oil - it's simply because the seals are old and leaky.  The molecules in synthetic are more uniformly small and can move though places that the mostly larger dino oil molecules does not (that's one of the reasons it lubricates better). Therefore you may observe a leak where it was probably unnoticeable before. You can change back to dino oil if you wish.

I also recommend synthetic fluid in the transmission & rear axle.  There the superior heat resistance properties of synthetic has value at almost any age of transmission.
 

Shayne

Well-known member
Joined
Jan 22, 2006
Posts
4,324
I've used Mobil 1 for many years and never even bother to check the oil in ant of my vehicles.  Restored antique cars and trucks and used it there  Synthetics are great. The last car of mine had over 370,000 miles on it, Daughter drove it 2 years and sold it to a neighbor, now has exce3ss of 500,000 miles on it with no major repairs.  It's an 89 Gran Marquis Mercury. My 92 Lincoln has over 200K on it and the wife's 2001 has over100K  Go for it.
 

Fizzban

Well-known member
Joined
Jul 31, 2006
Posts
60
Location
Memphis
WOW....

A lot of information quickly.  All seem to be pro...as I actually expected.  The Royal Oil Company is one that one of my relatives worked for back in the 70's I guess...they had this synthetic that was purple!  Imagine....I don't think too many people bought it then.  What a change since!

I think I'm gonna try it in all vehicles.  Even if I put it in the older vehicles, I can't help but believe it will still extend the life due to much better lubrication.  Thank you all!
 

Karl

Moderator Emeritus
Joined
Mar 3, 2005
Posts
5,154
Location
Elkhart Lake, WI for the summer. Work at Road Amer
What Gary Says!

Engine flushing? Hogwash! There are many small oil galleys in an engine crankshaft, camshaft, lifters, etc., that are not drained thru regular means. The only way to do a complete job without disassembly is to drain all oil, replace the filter, fill with new oil, run 15-20 minutes, then drain and repeat the process. Years ago we used to get the engine up to operating temp., drain, replace filter, do the initial refill with a 50/50 mixture of engine oil and kerosene, and then ran the engine for just a few minutes, drain, replace filter again, refilled with 100% oil, ran for 15-20 minutes, drained and repeated. The kerosene did a nice job of removing deposits and some of the varnish, but at some risk because of the lesser lubrication properties of the mixture; therefore the short run time. Synthetics are almost 100% compatible with regular oil.

Ron,
I've run Castrol in all my vehicles for many years, more recently full synthetic, and have never had a problem. About 7 years ago I tore down a 12-cylinder Jaguar engine with 140,000 miles on it, and miked the cam lobes, bearings, crankshaft throws and mains, piston skirts, etc., and found absolutely NO wear and no ash or sludge in the pan. I wouldn't use anything else. Did you have some problem that you could directly attribute to Castrol oil? I'd be interested to hear what it was ???
 

Lowell

Well-known member
Joined
Aug 15, 2005
Posts
2,221
Location
Tempe, AZ
I've been using Mobil 1 in all my vehicles since about 1977 after reading an article in Popular Science or Popular Mechanics on sythetic oils..  They had run a Lincoln with Mobil 1 for 100,000 miles as I recall.  The engine was then tore down and checked, much like Karl did, and everything was still within new engine tolerances. 
Jake
 

Shayne

Well-known member
Joined
Jan 22, 2006
Posts
4,324
Years before mobil 1 I used RPM motoroil in everything.  Worked much the same way 5000 milr change oil and filter.  When I worked as a Sales Rep in the 70's we had 2 Lincoln Town Cars, I switched cars with the wife every other week so she could have it serviced,cause I drove neaqrly 500 miles most days.  St Louis to Indy7 and  back, St Louis to Chi and back,  To KC and back, Memphis RPM used to be purple and as was Havoline in those days.  You could take an old car and change the oil and filter and let it idle and within 20 minutes you could hear the difference in the tone of the engine.   It would quiet down and Prrrrrrrrr like a kitten.  Good stuck Joe  was the old saying.
 

TheDude

Well-known member
Joined
Sep 12, 2006
Posts
45
Synthetic Oil

Advantages
The industry recognizes the following benefits for synthetic motor oils:

Improved viscosity at low temperatures. Mineral oils tend to include wax impurities which coagulate at lower temperatures. A typical 10W-30 oil remains liquid at -50 ?C (-58 ?F)
Better high temperature performance. Synthetic oils have few low molecular weight hydrocarbons which evaporate at high temperatures.
Higher purity
Decreased oil consumption
Reduced friction and engine wear
Improved fuel consumption through better engine lubrication
Resistance to oil sludge problems
Crude oil doesn't have to be used for the production of the lubricants
Some synthetic motor oil producers offer extended intervals between oil changes (extended drain intervals)
Reduction of environmental impact (due to lower oil consumption)
[edit]
Disadvantages
The primary disadvantage of synthetic oils is that they cost significantly more than mineral oils. Some manufacturers of synthetic oils, such as Amsoil and Mobil1, however offer extended drain intervals which allows for running the oil by over 7 times the length of conventional petroleum oils. This extended drain interval actually causes synthetics to be more cost effective over the course of 2 to 3 oil changes. However, with the recent rise in the price of petroleum the gap between the cost of a typical liter of petroleum motor oil and the typical liter of synthetic is almost negligible.

Anecdotally, synthetic oils can cause problems with older seals which are prone to leakage. As long as the vehicle or equipment in question is in sound mechanical condition then using synthetic oils should not be an issue.

full text can be found here.

http://en.wikipedia.org/wiki/Synthetic_oil
 

Gnuman

Active member
Joined
Oct 13, 2006
Posts
25
I have a 92 Subaru that I just switched over to synthetic, for many of the reasons mentioned above. One further advantage to synthetic oils (and a lot of the reason that they are said to make old seals leak) is that they have a greater detergent action, so a lot of the old deposits in your engine get washed away over time. This also means that they do not tend to build up inside your engine. How this causes the myth that synthetic oils damage seals is that, with time, the operating temprature of your engine will bake the seals to a consistancy of plastic, reducing it's ability to seal. With "dino" oils, there is a layer of varnish and other deposits between the oil and the seal. That is what is actually keeping the oil from leaking out, as the seals are already long dead. With the higher detergent function of synthetics, this layer gets washed away, and the defunct seal is seen for what it is. All of this to say that if you have considerable milage on the engine, it would probably be a good idea to replace your old worn out seals with new ones when you switch to synthetic.

Again, for all the reasons above, as well as the better cleaning action it provides, I emphaticly recomend synthetic for any engine you plan on keeping. . .
 

blueblood

Well-known member
Joined
Mar 16, 2005
Posts
1,082
I'm sure to be in the minority here but I have run the old fashioned oil for decades and mileages exceeding 200,000 on several vehicles and no problems so I just ignore the whole thing except for my diesel engines where I run only Valvoline Premium Blue.
 

Karl

Moderator Emeritus
Joined
Mar 3, 2005
Posts
5,154
Location
Elkhart Lake, WI for the summer. Work at Road Amer
IMHO, it's being penny-wise and pound-foolish to try extending time between changes to any great degree. While the syn. lubricants will last longer under higher heat conditions, they are still circulating products of combustion (moisture, smoke particles, etc.) and raw fuel from blow-by, and while the filters may catch the majority of particulate matter, you still have to drain it to replace the filter. Personally, I use either Castrol synthetic or Amsoil, but wouldn't run much beyond 7.5k before changing it. Thirty bucks worth of oil is still pretty cheap insurance. Heck, you burn that many gas/diesel fuel dollars in an hour or two of driving!
 

Gnuman

Active member
Joined
Oct 13, 2006
Posts
25
Karl, I have to agree there. The limiting factor in extended change intervals is the filter, which will wear out long before the oil wil. 'course, that opens up the whole "which filter is best" can of worms. . .  ;D
 

BernieD

Well-known member
Joined
Mar 1, 2005
Posts
5,877
Location
Goodyear, AZ
Gnuman said:
Karl, I have to agree there. The limiting factor in extended change intervals is the filter, which will wear out long before the oil wil. 'course, that opens up the whole "which filter is best" can of worms. . .  ;D

Gnuman

Not sure about your rig, but for diesels the limiting factor is the oil additive package. The filter does it's work but most contaminants are held in suspension in the oil by the additive package. After about a year, the additive package is either worn out or depleted, thus the need for an oil change. That is why the diesel engine manufacturers don't suggest the addtional cost for synthetics, you still have to change the oil within the same time period. The oil is still good and can lubricate just as well as new, but damage can be done to your engine by the contaminants, even with a new filter. As for "which filter is best" I only use the OEM filter. I'm not going to risk a $10-20k engine to save a buck or two on the filter.
 

AlGriefer

Well-known member
Joined
Mar 24, 2005
Posts
300
Location
Las Vegas, NV (when not traveling)
I recently sat through a series of seminars presented by Cummins, Cat, and Allison/Detroit Diesel reps.  The short summary of the comments on synthetics are:

1. Use synthetics in transmission, and differential without fail.

2. Synthetics are generally better than Dino oil and provide more uniform lubrication.

3. Do not, repeat, do not extend change times without instituting a program of regular oil analysis.

4. With analysis, generally, pleasure use owners can extend the change intervals on both types of oil.

Me, I'm staying with Dino oil in the engine and synthetic in the trannie.

Al
 

Ron

Moderator Emeritus
Joined
Jan 29, 2005
Posts
18,082
Location
Home is where we park it
I have used Amsoil in all my vehicles since around 1974 with very good results.  Had a Chrysler that we bought used in Canada with 40K miles on it.  Changed to Amsoil, installed bypass filter, never changed oil again but did change filters and had oil analysis done after 50K the 100K and 150K.  Sold the care to m,y nephew and the car had over 250K miles since new when they sold it. Have no idea how many miles the next owners put on it or if they ever changed the oil.

I am a firm believer in good synthetic oil like Amsoil or Mobil 1.

While I have never extended the milage on the Eagle the recommended change interval is 15,000.  I change the oil once a year regardless of milage since we never exceed 15K a year anymore.
 

BernieD

Well-known member
Joined
Mar 1, 2005
Posts
5,877
Location
Goodyear, AZ
AlGriefer said:
I recently sat through a series of seminars presented by Cummins, Cat, and Allison/Detroit Diesel reps.  The short summary of the comments on synthetics are:

2. Synthetics are generally better than Dino oil and provide more uniform lubrication.

Al

I have been to at least 3 Cummins/Spartan seminars this year at which oil was covered. While benefits of synthetics were acknowledged, the cost differential for engine usage was not deemed worth the benefits .


3. Do not, repeat, do not extend change times without instituting a program of regular oil analysis.

4. With analysis, generally, pleasure use owners can extend the change intervals on both types of oil.

I have never heard Cummins approve of extended oil changes. Oil analysis will indicate impurities in the oil and engine damage, but it won't provide information on the oil additive package. That was the primary concern of the seminar presenters as to oil change timing. The basic Cummins position was that if you used extended oil change timing due to either using synthetics or oil analysis, Cummins may not honor the engine warranty if damage was due to oil.

Me, I'm staying with Dino oil in the engine and synthetic in the trannie.

Me too :)
 
Top Bottom