extra-virgin olive.

The other posters are right, switching to synthetic might cause any leaks to worsen initially. It is my understanding that synthetic will clean your engine's seals (old oil gunk etc.). With the old buildup gone the seals will leak initially. Then the synthetic will rejuvenate the seals and the leak should be reduced or go away. It does take a little time. Be patient.

This is exactly what happened when I switched power steering fluid from regular ATF to Mobil 1 ATF due to leaky seals in my 850's steering rack. Leaked more at first, now it doesn't leak at all. Probably saved me the cost of replacing the steering rack...:) What a bargain!

If NOT using a synthetic, I reccomend DELO as a good dino oil. I switched to it many years ago, (from Castrol) and my flame trap stays clean and I've had excellent reults in using it. Of course I do change oil and (Mann) filter every 3k miles like clockwork. I usually get the DELO in a case from Costco, depending on the local sales.

Hi,

I used to use Mobil Clean 5000 10w 30 (regular oil).

I switched both vehicles 1990 244 (has 249,000 miles) and 1992 245 (has 199,000 miles) to
Mobil 1 High Mileage 10w 30 (synthetic oil) several months ago. The reason I switched over is both my wife and I work close to home and I also wanted to extend the oil change intervals.

The Mobil 1 High Mileage Synthetic is supposed to condition seals on older (higher mileage) vehicles so there is a low possibility of any leakage from the switched over-at least that's what I read on the Mobil 1 website. Either way the Mobil 1 High Mileage was the same price as the regular Mobil 1 so I figured it couldn't hurt.

It's also a good idea if your car is switched over to synthetic, to change the oil filter around 1,000 miles after the first fill up of synthetic.

And as another suggestion-use a Mann oil filter (as most will agree on here, it is the best/most reliable oil filter to use.) You can order a case of 10 filters for around $40 at FCP Groton, eEuroparts, etc.

Travis

You opened up a can of worms with this question.
Many love the idea of synthetic.
Althought it is supposed to be compatable and the manufactureres say there is no reason why this should happen, Many people do get leaks out of the Engine seals when switching to synthetic.
Synthetic is good for Starts in very cold climate because the oil doesn't thicken up in the cold.
For what it's worth.....I live in Lower New York. I do not use synthetic in anything I own. I have several cars(different makes) with over 300K miles on them. I have a motorcycle that is nearing 100K miles on it and I have always used plain old Castrol GTX 10-40; oil changes at 3000 miles.


--
'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me http://home.lyse.net/brox/TonyPage4.html http://cleanflametrap.com/tony/

http://www.bobistheoilguy.com/motor-oil-101/


First, do you live in an area with cold winters? Do you take short trips around town more than long distance? Either way here is the answer.

I use 10w 30 regular old oil. Mobile 1 has been on sale more recently so I've gone with it over my long time use of Valvoline. But with the next change being in the winter and having read this link I posted my next change will be with synthetic. Why?

Because its thinner at start up and sticks to engine parts longer. Its at start up that the engine has the most damage done and the thinner the oil the faster the lubrication will happen. In winter especially the synthetic choice looks to be the way to go.

I've read here on the brickboard that if your car hasn't been running synthetic its best to change the oil filter after so many miles. I'm guessing about 1000 or so since the synthetic somehow knocks free some of the dirt and stuff in the engine. Either way the link is a great read and I may have bookmarked it from another brickboarder's post in the past so thank that person.