My problem is I'm a realist. I know how things should and do work when you do it right. But I also spend a good portion of my time in the streets talking to "mechanics" and people, hearing so many war stories and absurd myths that make for a book.

Yesterday while I was talking to the owner of a store that sells oil and filters when a "mechanic" came in and asked the price of transmission oil. The guy asked which one and he said "140". The store owner said I have one for $5 and one for $5.50. The mechanic said the $5 one. No specifications on the pail it was poured from.

Agreed Richard.

The problem with those complaints is that they lack details.

• From a mineral of what viscosity and what API category?
• To a synthetic oil of what viscosity and what API category?
• What period of time/miles was the new oil used?
• Where were the leaks?

After analysing this data, there additional questions, but those are the first four before drawing conclusions.

A lot of Mini owners that have tried full synthetic oils have complained that their Mini seemed to leak more. That being said i know of a few owners that run synthetic in manual gearbox Mini's with no issues.

I like all the feedback Next I'll call amsoil and see what they say. thanks

That is really too good an oil to ruin with additives. It is properly balanced and has very good technical specs.

As far as engine life, even with the abuse of short trips, long idles to cool down or heat interiors, about 3% of all US cars make it past 200,000 miles. Of the remaining 97% I'd bet a significant portion are wrecked. Too many people just get tired of them or stop taking care of them. Many end up with convenience store oils that are garbage.

As long as you take care of your oil, coolant, and timing chain, it is not difficult. I had one pickup with 400,000 when an idiot left the air filter wing nut where it could get sucked into the engine, which, of course Murphy obliged. I currently have two more around that range, and all have been mid-sized, not the F series or their likeness. Neither of them uses oil between changes of 5000 miles. My F550 is nearing 200,000 and it has been a problem truck, but for poor fuel and poor Ford recommendations for off-road use and some stupid employees.

Richard so will adding 8 oz  additive change that much to 20/50 amsoil ZROD ? let me clarify in my first post I said most of the vehicle's
i've  owned I used prolong in. and pro's or cons one vehicle on over 260,000 miles does not use any oil in between oil changes 160,000 on another just lucky? now the booster every oil change is just 8 oz but never used in a classic mini cooper so is 8oz of a friction modifier
going to hurt that's why I put this post up to see if any mini owners have had any experience with this.Thanks

The viscosity curve for a synthetic 10W-40 and a mineral 10W-40 are basically the same when they start out,  but over time, the mineral ones start becoming a 10W-30 from polymer shearing. How much they change depends on the quality and the application.

Oh, do Synthetic maintain their viscosity???even when engine is hot?? Good, Im gonna start using synthetic oil,, give more cushion effect between moving metal parts.  Thanks for the info Rich

Thank-you Richard, for providing the factual, expert knowledge.

(I have been skirting around in general terms what I expected you would say. I'm sure you've said it here before, and in even mere accurate detail, though i don't have the time or energy to find it.)

I've been in the oil business, studying and doing root cause failure analysis of problems from engines to heavy machinery. Unfortunately I've seen way too much. 

If you start with a good oil (not the stuff on the market 20+ years ago ) most additives do nothing positive, and in the long run can do damage. A good oil is a "perfect" balance of additives for cleanliness and wear protection.
-- You can put in more anti-wear, but you will have more deposits in the rings and end up with stuck rings or overheating from other deposits. This is what things like ZDDP Plus do. Also things with Moly, and other anti-wear compounds.
-- You could put in more detergent, but end up with more wear.

There are dozens of studies (including Dupont, who makes it) that say Teflon does nothing in an engine.

The additives are suspended in carrier oil. That can be thin or thick, changing (slightly) the viscosity of the oil. They are usually aromatic oils so they are more soluble. Those loose their viscosity at higher temperatures and evaporate.

A SAE 90 gear oil is the viscosity equivalent of a SAE 40 or SAE 50 engine oil (wide categories). But very different additives. A good engine oil (diesel formula like a CI-4  or CJ-4) has enough anti-wear additives for the transmission, and our transmission gears are designed for the torque applied with that protection. If you doubt it, analyze the oil. I've analyzed about 5000 samples.

The demonstrations of how much extra pressure you can apply with the additive is valid in industrial gear boxes or differentials. Not engines.... remember the balance you need.

Most Mini's will run fine for a long time on 10W-40, needing only to go up to xW-50 once the bearings are worn. The oil pump generates a ridiculous amount of flow/initial pressure. The cheaper 20W-50 oils will loose their viscosity as their polymers are chewed up. The better ones (read more expensive) will have better base oils as well as less and better polymers. Good (PAO based) Synthetics do not use polymers so they will maintain their viscosity.

The only additive I'd use is something like AutoRx occasionally (50,000 miles or so ) to clean up any residual deposits in the ring lands.

Really !!!!!! Wrong again tb. And just for the record i did not recommend it for Mini's. And no i am not a distributor for Amsoil.

Re-read what I said about the operating conditions for engine oil, transmission oil and differential oil. 3 environments, 3 lubrication  conditions. Many modern cars use engine-grade oils (5w30 etc) in the engine, something similar or heavier in the transmission, and if they have separate differentials a heavier oil like 90-weight gear oil. Change rates are different for each drive-train component. Engines are hottest and get contaminated quickly. Transmissions get quite warm and collect more metal filings because of how the many parts move in and out of gear, slide, grind and suffer driver abuse. Differentials just sit there happily doing their job, always in very closely-aligned mesh and only getting even, steady wear.

In a Mini engine, the same oil does all three jobs at the same time. An additive might be great to quiet upper engine noise because you can't be bothered to set valve lash regularly, but what's it doing to the differential? Or adding a treatment that makes your oil pressure DROP??? when you need it highest?

Amsoil is too overkill for a classic mini,,,, Amsoil is for racing application only.
Castrol is for everything: minis , boats, riding and push lawn mowers, weed eaters etc. very versatile oil.

Not true. In fact Amsoil is one of the better synthetics out there.

amsoil=pyramid scheme......and all it is is every other companies sloppy seconds...... The bottom of the barrel scrapings

Well I had a Volvo 145E at one time and the transmission required gear oil NOT engine oil. With all the nonsense that people espouse ... who knows what's right.

I wont think twice in using oil additives, these oil additive comapanies like the MMO marvel mystery oil have been in the market for 70 years and as well as the sea foam and lucas. 
I know jeremy thorpe said when he used Amsoil synthetic 20W50 on his moke, the crunch on his second gear was completely gone. Well, 4 cans of Amsoil costs $120, it should surely do wonders.

I see what your saying thats why I hope we get a lot of opinions and feed back a lot of Mini owners out their jet motors swears by amsoil 20/50 ZROD he says it's thick not like other thinner synthetics. Also prolong is only an 8 oz additive. Also helps that slight dry startup.

IMHO This is just not true.  Many manufacturers - like Volvo (mine was an early model so may no longer be true) used engine oil in the gearbox....  With change intervals of something like 100K.

Its more likely that the trans doesn't like running in polluted engine oil than the engine objecting to the gears doing bad things to the oil....

Cheers, Ian