I have been using Mobil 1 in all of my cars for years. I do it for longer maintenance and extreme operating tempatures here in Iowa.

 

Here we go again...

Tell ya what... use whatever you want. If you think the reason your oil leaks are gone is the oil, then fine. If you want to keep throwing money away every 3K miles by chaning oil and filter, do it. The reasons for synthetic are many. Oil change intervals are one of them, with the proviso that your filter can handle it.

 

I've been using syn in all my gear boxes, xfers, and diffs. I gained 2 mpg. I also use syn in all drivetrain including the engine in my TR-6. It leaks but it always has, ITS BRITISH. Runs better, shifts better. Petro based oils start breaking down once they hit an operating temperature. Drive it once, park it for 3 months, change the oil. Syns dont break down from normal heat. Acids build up with petro based oils from moisture.

 

What is the normal time/mileage needed for break-in? (different car)

 

At 10,000 you should be good. Its the number I have always used.

 

is it me . . .. But when I used dino oil at around 3-4k my oil would be dark brown kinda dirty and after switching to syn mobile 1 even after 5-6k my oil would look almost the same(pretty impressed). It's been 4 years since I switched from dino to syn and I'm not going back. I personally believe that I get my $$'s worth using mobile1 syn.

 

AH64ID,
Where can you buy Amsoil?

 

I buy it at amsoil.com; if you look on the website it should say dealers local to your area. Somtime dealers also list in the phone book.

 

You can also get amsoil from Bob_98SR5 (one of our mods on this board). He is a dealer. I buy my stuff from him.

 

On every vehicle we've ever had, we'd switch between synthetic and mineral all the time, and all of our vehicles have lasted well over 200k, with no smoke and ticking.

Oil changed regularly every 3 - 3.5k

 

I used to work at a lube shop and this was a big issue. Mobil1 is proven to be a better oil grade as we know and it has it's proclaimed "anti-wear technology" If it were me, I wouldn't make the switch on an older engine, maybe a younger (80,000 or less) and for sure on a rebuilt or new. Synthetic does do a better job to prevent wear reguardless of the brand, synthetic also has some additives to swell seals, but doesn't do as well of a job in that particular area. From my history I have never seen synthetic to cause a leak or cause problems. It all comes down to about the same price seeing the longer change intervals with synthetic. But anyways...hey theres always a dura-blend half and half when you can't really decide.

 

Just changed to Syn in one of my other cars on Sunday. 50 miles later, still running. So far so good.

 

Excellent forum for oil, lubrication, etc.: http://theoildrop.server101.com/cgi/ultimatebb.cgi

There is no problem switching back and forth from synthetic oil to dino oil ina properly operation engine.

This is pretty good info. Though, synthetic won't dramatically reduce wear, unless your typical operating conditions are either very cold (including lots of cold start-ups [below 0 deg F]) or very hot. The main way it helps during the cold is that it flows better than the same viscosity dino oil. And remember, engine wear is greatly increased while the engine/oil is cold. The main way it helps at high temps is that it is less susceptible to high temperature shearing than a dino oil.

It is true, that it will take a few synthetic oil changes to clean out your engine. But there are ways around this, and ideally you would do one of these. LC20 (http://www.lubecontrol.com/index.htm) is excellent at cleaning the engine faster than synthetic oil changes alone are (and at keeping the engine clean).

The best, in my opinion, is Auto-RX: http://auto-rx.com/index.html I highly recommend this stuff.