By sg on Tuesday, May 29, 2001 - 10:59 am: Edit

Would love to hear everyone's opinion on this one.
My Disco II only has 13K.

1. If I start using synthetic should I keep using it forever? I hear its bad to switch back on forth. Recommendations?

2. Will synthetic oils extend the life? What about Slick 50?

thanks in advance.....

By Mike on Tuesday, May 29, 2001 - 11:20 am: Edit

Everything I have every read about Slick 50 is bad. The teflon doesn't really coat the engine, instead it gets stuck it certain places and can impede oil flow. I'd stay away from it.
I did have good experience with Mobil One though. I had a '93 Cherokee that I started using Mobil One in at about 10K miles. The engine after 150K miles still was running strong and didn't burn a drop of oil. Most people believe that you should let your car break in for about 10-15k with organic oil first. I just bought a Disco w/ 29K, and I'll probably switch to Mobil One.

By Jon on Tuesday, May 29, 2001 - 11:23 am: Edit

Here's my experience and knowledge of the topic:

Synthetics are great for prolonging the life of an engine. Synthetic oil reduces overall friction and penetrates and lubricates much more completely than organic oils. And, in my truck's case, switching from organic to Mobil 1 cured my oil leaks after about 10,000 miles.

Once you start synthetics, you can never go back (well, okay, you CAN, but it is highly inadvisable). But, you cannot alternate between the two.

New engines need to be broken-in on organic oil. Some people I know start running synthetic as soon as they buy a new vehicle. This isn't good for a couple reasons. For one, the rubber seals in a new engine need to be soaked in organic oil as they wear-in. Synthetic oil somehow doesn't lubricate them as necessary, so the seals never really set-in correctly. Another reason is all the valves and new piston rings, etc., need to wear against each other to get all the little metal shavings off so they work properly. Organic oil allows this, but synthetic oil lubricates too well, so to speak, and the metal parts of the engine don't generate the necessary friction to wear each other in correctly. This can cause you problems down the road.

However, since your truck has 13,000 miles on it, it's more than likely broken-in. If you would like to switch to synthetics, now's a good time. Your engine will certainly see a longer service life with reduced wear over time. But my advice is switch now and stick with it. Oh, and if you take your truck back to the dealer from time-to-time, make sure you tell them you're using synthetic oil and not to change it, unless they're willing to accomodate you on that. My dealer has a strict shop policy that they can't change synthetic oils, as it's not the shop's standard oil, so they don't have the recycling ability to handle it, or something like that. Anyway, hope the info helps.

By Ron on Tuesday, May 29, 2001 - 11:28 am: Edit

I don't get why you can't go back and forth. Seems counterintuative to me, especially given the presence of synthetic blends and that it says you can mix synthetic with regular right on the bottle.

Ron

By RVR OVR (Tom) on Tuesday, May 29, 2001 - 11:29 am: Edit

I have heard that going with synthetic on an older engine (my case 66K) can actually result in more leaks because regular oil won't leak out where synthetics will. anyone experience this?

i was going to switch over after i ran out of my last case of oil, but was going to hold back for this reason.

tom

By Milan on Tuesday, May 29, 2001 - 11:40 am: Edit

I only heard of synthetics leaking where organic would not. I know that there are additives you can use that cause seals to swell up and stop leaks with either oil.

I have been switching from organic to synthetic and back as I please (or as what oil I happen to have). I have even mixed organic with full synthetic (better than no oil at all). All to no ill effects so far (fingers crossed). I just switched my Disco to synthetics everywhere about 3 weeks ago. I'll have to check that front main seal leak to see if it leaks more, less or the same.

By Jarrod on Tuesday, May 29, 2001 - 03:46 pm: Edit

I've done a lot of research on the use of synthetics, and I've converted many cars/trucks to use synthetics (7 cars and my own Disco). All the cars and my Disco have been converted to AMS oil while keeping the oil weight the same. Here is what I've seen.

In EVERY case, its made the vehicle run better. What I mean by better is 1) the engine idles smoother, you can hear it and you can feel it, or actually the absence of feeling it. 2) the engine revs to higher RPMs faster - its not going to win any races now, but there is a noticeable difference. 3) the engine seems to stay cooler, more noticeable with 4-cylinder cars because the electric fans kicks on less. 4) at higher RPMs (over 4000 rpm) or speed (around 80 mph), again there is an absence of vibration from the engine. 5) there is no difference in the leaking of oil from organic to synthetic - they've leaked the same amount (only the Disco leaks of course). So these are my observations, and in every case its the same.

Now this is what I've found out. Synthetic oils do not make cars leak, but they do have detergents that break down deposits formed when oil starts to break down. In most cases, what happens is that there are minor leaks which have been sealed up by the deposits from burned organic oil. As the synthetic oils with detergents go through and clean this out, it causes those deposits that previously held oil in to break down and thus leak. So the seals were bad to begin with, the organic oil was just a band-aid for the problem. To get a certain grade of oil, organic oil is distilled until they get a blend that fits the range they want, i.e. 10W-30. What that means is that its comprised of really small particle chains, and really large particle chains that when mixed and tested give the desired range. This mixture can give problems as some particles break down faster than others - and not giving the protection it potentially could. Synthetic oil has a more uniform mixture, giving if not a more accurate mixture - at least a better representation of what the weight should be. In addition to this, synthetic oils can be run longer or harder then organic oils extending the duration of oil changes because of its high thermal protection ability - it resists breakdown better then organic oil (it eventually will break down of course). Its still a good idea to change the oil on a regular interval, and shorter if your hard on your vehicle because of metal shavings and whatnot, but I routinely change my oil at 6000 miles instead of 3000.

As far as synthetic blends (synthetic/organic blends), I don't care for them. I think its a slipper slope idea. The idea is that you get the protection of synthetic oil at the price slightly higher then organic. In my opinion any amount of organic oil negates the benefit of synthetic as some amount of organic oil in the mixture will break down quickly - again not protecting the car to its potential. You get what you pay for, something better than organic, but not quite as good as synthetic. Just my opinion. If you can afford to use synthetic, I'd say stick with it. The downfall of synthetic is the fact that is expensive, and multiple oil changes with organic still is cheaper then 1 or 2 synthetic oil changes even with the longer interval, but I think the fact that we've all paid for such an expensive vehicle, that the extra 15-20 bucks each oil change is worth the investment in the long run.

Synthetic oil was first developed for turbine engines because organic oil couldn't withstand the extreme temperatures the turbines produced. The technology eventually filtered down to use in cars. Not to open another can of worms - there is a difference between synthetic oil (Castrol Syntec, AMS, Redline) and oil additives (Slick 50, Duralube, Lubramoly, Motor-Up, and other such products).

Just change your oil often.

By Jarrod on Tuesday, May 29, 2001 - 03:47 pm: Edit

Sorry for the long post

By Blue Gill (Bluegill) on Tuesday, May 29, 2001 - 04:08 pm: Edit

very informative - I want to use synthetic, but I'm afraid that all my deposits will wash away and I'll be leaking like a sieve I plan on going full synthetic after I replace my head gaskets, oilpan gasket, and *yikes* rear main seal...

So, what is the best synthetic and best weight to use for hot, dusty, arid desert climate?

By bill on Wednesday, May 30, 2001 - 12:59 am: Edit

my two cents worth:

1978 Toyota P/U. Put Mobil 1 in after about 10,000 miles (Mobil says to break engine in w/ organic oil). 170,000 miles now. Crankcase is spotless. Never leaked any, ever. (But I doubt that synthetic/organic had anything to do w/ that.)

1984 Toyota 4Runner. Ran Mobil One for 140,000 miles from new (after 10,000 mile organic break-in). Crankcase clean. Zero engine problems. Never a leak.

1993 Infiniti J30. Ran Mobil One from day one after breakin. 120,000 miles now. Zero problems. Crankcase clean. No leaks.

1996 Discovery. Oh, well.... Have switched between Mobil One and organic (thanks to the ineptness of the local dealer not following instructions). Mostly Mobil One for 130,000 miles. No engine problems (knock on wood) as yet. About a quart of my $4/quart Mobil One leaks out every 1000 miles or so. Crankcase did not stay very clean unfortunately -- likely due to running organic oil (thanks to dealer) for a couple of 10,000 mile periods.

My bottom line:

synthetic oil doesn't break down as much at high temperatures -- doesn't form as much engine crankcase varnish.

likely adds around 2-5% to gas mileage - i've never tested this scientifically, but I tend to get 1-2 extra mpg driving my cars over the "norm" and drive them pretty hard.

probably doesn't have anything to do with leaks -- although some evidence that Discovery leaks more when running Mobil One. perhaps the built-up organic "sludge" DOES help stop leaks in cars w/ poorly designed seals like the LR.

I think Mobil One is a plus overall, particularly if you use car hard or go max between oil changes.

I don't see any problem switching between the two, but running organics in the crankcase defeats the purpose of keeping it clean of varnish. All the synthetic manufacturers claim their oils are 100% compatible w/ organics - and Mobil even markets a mixture oil now (beware! - don't get fooled buying it thinking it is non-organic).

Likely most of the synthetics are all about the same -- not sure I buy the "teflon" stuff however. I just stuck w/ Mobil as it was one of the first ones available.

bill

By Moe on Wednesday, May 30, 2001 - 02:05 am: Edit

Much ado about nothing. Synthetic/Dino oil? For our purposes the regular change is more important. Change the oil and filter frequently and that will likely extend the life of the engine.

Great post Jarrod. You're right, if you can afford the synthetics that is the way to go.

Ian

By Travis Chrystal (Travisch) on Wednesday, May 30, 2001 - 10:49 am: Edit

Jarrod is pretty much right on the money just not a believer in extended drains. I run the amsoil 0W-30 in my 98 disco without any problems or oil leaks. I switched over at 40K. I also use a bypass filter for extended drains and run full synthetics through the vehicle. I've got a smoother running engine and get an average of 17-18 mpg. The best bang for the buck was changing the ATF - shifting really improved.
If anyone is interested in AMSOIL I provide it at cost to readers of this board - e-mail me.
travisch@avaya.com

By Grayson on Thursday, May 31, 2001 - 01:04 am: Edit

Q:Why do Synthetics cause supposedly more leaks?
A: Synthetics have very good flow capabilities, even at cold temperatures. If you have any kind of sealing problem, a synthetic oil is going to find it. Next time you're changing your oil and filling up the crankcase with synthetic, notice how easy the oil flows out of the bottle compared to conventional oil.
I use full syntheics in my truck, a '88 RR,(engine,diffs,t-case,tranny)and picked up about 2 MPG not to mention less gear noise.

By NICK on Thursday, May 31, 2001 - 08:45 pm: Edit

as far as synthetic oil goes,(MOBIL1 in particular), do they make diferent weights or is it only 10w30,I want to start using in 96 with 37,000 miles ; any suggestions?

THANKS

By dave on Friday, June 01, 2001 - 03:25 am: Edit

You can get the Mobil 1 in 15-50w. That's what I run in ours.

By Jon on Friday, June 01, 2001 - 12:13 pm: Edit

Mobil 1 is available in 0W-30, 5W-30, 10W-30, and 15W-50.