Home Forums Gear Hunting Trucks and Four-Wheel Drives How many of you guys use synthetic oil?

I have Amsoil synthetic gear lubes installed in diffs front and rear, plus transfer case and 5 sp. tranny. I have used the Amsoil engine oil in the '96 Dodge Cummins diesel, but currently use 10-30 Rotella in winter and 15-40 Rotella from April to November. The Amsoil is pretty good stuff....especially at -30F.

I use Castrol Syntec in my Ranger. It has 235,000 miles on it.

I use mobile 1 in my wife's Accord, and pour it into every hole I can find on my pickup. I've got 147K on my Tacoma, and figure it's about a third worn out. I a mechanic adjust the valves at 130K and he told me there was zero wear in that part of the engine. It's worth the extra money to run good oil.

I used nothing but Pennzoil 10w-30 in a '97 dodge dakota that I had. It was run all day without shutting it off in the gas patch. When I got rid of it it had 160,000 plus miles on it. I had the oil pan off of it once and it looked like new inside the engine. I used to be a believer in synthetic oil but after performance like I experienced with just plain old Pennzoil I don't think the extra cost is worth it for synthetic. The main thing no matter what you use is to change oil often.

Running an engine all day is much easier on it then multiple start stops, especially cold starts.

I use Syntetic in a vehicle after its broken in would not use it on a brand new vehicle.

Why not?

These cars use Mobil 1 full synthetic as factory fill

Aston Martin
Bentley
Chevrolet Corvette
Dodge Viper
All models of Porshe
Mercedes AMG

These are some pretty high end cars. If they think its OK to break an engine in on synthetics It must not hurt anything.

I haven't ever used synthetic oil. Here is why.

Synthetic oil is better oil in terms of maintaining viscosity. It flat lasts a lot longer than petroleum oil. However, all oil gets dirty, and unless you have a bypass oil filter system, you still need to change your synthetic oil at the same interval as regular oil.

Also, there is an important point to consider with a diesel. The recommended grade is 15W40. Synthetic oils usually come in a lower low-end viscosity, like 5W40. This means they are a bit lighter weight, but because of their superior viscosity break down resistance, you can get away with a lighter synthetic oil and reap all the benefits of a lighter oil.

That is all fine and good until you throw a dieasel engine into the equation. Diesel engines run a static compression of around 17-1, and when you add in the turbo you get very high cylinder pressure. This high cylinder pressure puts a lot of "squish" on the rod and main bearings, and if your oil is to thin it will squish too much and can cause increased metal wear.

This is why I run Shell Rotella T 15W40 in my 125 HP chipped DMax and change it every three months. If I ever do go to a synthetic, it will only be after I install a bypass oil filter. I will then run oil analyses every 3000 miles or so to see how long I can run the synthetic before it breaks down/gets too dirty. A friend who did this with Amsoil said, IIRC, he could go about 30,000 miles on the Amsoil with the bypass filtration system, but that did include changing the filter and adding a new quart or so of oil every 6 months or something like that.

Non synthetic changed at 3000 miles every time.

fwiw,
I went a little overboard with my 94' F150 4x4 and installed an Amsoil Bypass Filter Housing AND a Preluber. Never started from a dry bearing after 10,000 miles. Ran Amsoil and Mobil 1 in the engine, Amsoil ATF in the transmission and transfer case, and Amsoil Gear Lube in both Hogs Heads. Tried to take similar care of the rest of the truck. Everyone laughed until I sold it last year for $10,000(without ever putting a for sale sign in the window). Blue book was $6200. Only thing that was nonoriginal were Goodyear EPDM Hoses, 31x10.50 BFG ATs, and the oil system. Drove the truck for ten years and got more than half of the original purchase price out of it...

That said I now use Shell Rotella in my 03' Excursion Diesel. I thought a lot about going with various synthetics, however, my father has five N14 Cummins at 400 HP and up, and one 3406E Cat at 550 HP that all run on Shell Rotella 15-40w. Some of his trucks have a 1,000,000 miles on them without so much as a set of main bearings... That and there's always cases of Rotella T at the shop...(grin)

Regards, Matt.

I was asked why I would not use Synthetic oil on a new engine. I worked on the the North Slope at Prudoe Bay in
the late 80,s. The new Ford diesel pickups that ran synthetic
oil from day one had multiple failures, determined to be improper breakin. The new Ford diesels that were driven up
with regular oil had no problems.

I knew a contractor for Bechtel and Aleska that did engine rebuilds in Fairbanks. I ask him why the engines failed at such low miles? He told me being how none of the trucks where equiped with Hobbs meters no true picture comes clear about mileage, as the engines run 24 hours a day 7 days a week. At that time the oil in use was DN-600, Trade name was Polor Start. I have not seen this oil on the market for many years. I would recommend a good synthetic oil to anyone no matter where they are or what the conditions are! I know for a fact that no high rpm (60,000) engine in this world could live more than seconds without a synthetic oil. If it afords protection at high turbine speeds what will it do for an engine that might hit 7 grand once in awhile? A side note to history I get a kick out of is the statement that the "Germans could never have developed the jet engine with out synthetic oils". One thing you never hear anyone talk about is the moisture content of ash based oils, they are loaded with moisture! Synthetic's, NADA! So if you think pouring water into your crankcase is a help, 'Go for it"

Synthetic is also now used in all BMWs. I have a 3 series, and recommended oil change is 15000 miles.

I had a Mercur XR4Ti turbo and the mechanics seemed split on the issue of synthetic vs. fossil oil when running a turbo. Some claimed that since synthetic was "clean", it would keep those little bearing from getting "dirty". Others claimed that synthetic didn't dissipate heat as well as the fossil and that heat kills turbos, not dirty bearings.

I ran synthetic in it until I found a sucker, I mean enthusiast, to buy it and deal with its idiosyncrasies and parts issues. It was a fast and fun car, but like women of that nature, it required a lot of attention, upkeep, and $$ to make it happy.

Jeff

Bought a surplus cop car from the Spokane Police dept. in 1992 that had used synthetics and I just kept using Mobil 1. I drove it for about 80K and gave it away to a friend of mine who was driving it at about 285K and it was still going strong when it caught fire from a leaking fuel injector. I don't think it had much maintenance after I gave it away with about 190K on it. I talked to the mechanics at the Spokane PD and they had experimented with synthetics doing a teardown of a dino and synthetic engine (Ford 302's). He said the dino oil engine showed some wear and had the typical varnish patterns they expected to find. What surprised them with the synthetic motor was the almost total lack of varnish and virtually no cylinder wall wear.
I use synthetics in the wife's '93 Intrepid and the '83 944. Using Chevron Delo in the '89 Suburban with 200K on it just because that's what was being used in it before I got it. I'll start using the the Wal-Mart $12 jug of synthetic now. Thanks for the heads up on that!
Synthetic in all the drivetrain. My understading the gearboxes really benefit from the synthetics. No sucking water into the mix and lower running temperatures.
When one of my daughters was still living at home we put synthetic in her '89 Mazda RX7. OOPS! Bad move. I didn't know it, but evidently the rotary engine needed dino oil only. It sucked that synthetic oil up in less than 1000 miles. Put dino oil in and no problems.
I do use good filters and try not to go more than 5K with synthetics.

I run M1 in my '94 F250 and my '99 Harley FLHTC.

You could really tell the difference in the Harley! Cut engine noise considerably. Now all you can hear is the rumble of the pipes ! ! ! <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />

mrmarklin,

not that I'm skeptical or anything, <img src="/ubbthreads/images/graemlins/cool.gif" alt="" />, but BMW changed their oil change maintenance recommendation from 7500 to 15k miles at the same time they started offering free maintenance for the first 4 years or 50k miles. Imagine that! <img src="/ubbthreads/images/graemlins/grin.gif" alt="" /> <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />
Do yourself a favor, change that oil every 5-7 k if you plan on keeping it a while........

badger

I used Mobil 1 in my 4.0 Jeep Wrangler and the rear mainseal leaked like a sieve at 19,000 miles.I know the design of that rear main is a problem but I think the synthetic made the seal problem worse. I have used Pennzoil ever since.

Pour it in a smoker and it stops the smoke long enough to get it sold to some one unsuspecting. So decide if the used car has synthetic before buying. That advise came from an Auto Auction owner.

I use M-1 in three of my newer vehicles, I use a blend in my old cars. I use M-1 10 W 30 and I can see that it does improve fuel mileage, but I have done so many modifications to my vehicles it is hard to say how much of it is strictly oil related. I have a 96 Impala SS that has had a Callaway (sp) conversion before I recived it from the factory it gets in the high 20's mpg with 433 hp. My wife's 98 Navigator has 135,000 miles and uses no oil between 4,000 mile oil changes. I did a few mods to it also. I found the line of code in the software for the 99 mph speed limiter and whacked it, when it was new. The Navigator does not get great mileage, but it is a 4WD with 373's. My Ford truck on the hand gets 22.5 mpg with 355's and is a 4 door that is 4WD, killed the speed limiter in it too. This may stir up quite a discussion, but most of the synthetic oil that is sold in ths country is made in the Mobil Synthetic Oil Plant in Beaumont, TX. I have an old class mate of mine that manages that plant and I went down there a few years ago for the 25th anniversary of Mobil-1 oil and was shown all the different brands of oil that are bottled at that plant. I can't say the brands they bottle, but the only one that has been mentioned in this discussion that is not made by Mobil/Exxon is AMSoil. Although, most of the different brands they bottle have a different blend to meet the stated specifications. I do not follow the recomendations of changing the oil filter every 5,000 miles and replacing 1 quart of oil as Mobil has quietly stated for the last 20 years, I change filter and all of the oil every 4,000 miles, you could get away with 5,000. When M-1 was engineered in 1975 it was tested at one oil change every 25,000 miles with 4 filter changes. Then GM and Ford as well as all of the rest of manufactures fell out and stated that the warranty would be void if this procedure was followed, so Mobil for a time said that you could run M-1 to the longest oil service interval, which is twice as long as the suggested interval that the manufacturer states. Now, Mobil/Exxon loudly states the 15,000 mile interval is in effect NOW with two filter changes. In any case any synthetic oil protects at a much higher temperature and does cut down on wear. You really can't make the claim that it is cheaper to run synthetic oil, but if you're like me you run it as a piece of mind. If you really want to know how the synthetic oil molecules lubricate I will send you a detailed report I wrote about 20 years ago, when I was an engineer. I an not an engineer any more, I am just retired.
Have a good weekend!
Marcus,