Real world feedback on Mobil 1

[gr8fl4porsche]

If you are trying to decide between dino oil and synthetic - I thought I would share my experience. I do not want to bring up the discussion about which is better - just tell everyone what can happen when you do. If you don't worry about oil leaks with synthetic, maybe you should.

I recently switched to Mobil 1 in my 87 Targa and the wifes 98 Subaru. The 911 was previously dry and now has about 6 visible leaks on the garage floor. Not real bad leaks but does leave spots on the floor. The Subaru leaked enough to cover the entire bottom of the car with oil, small puddles on the garage floor, and smoking exhaust and cat.

This weekend I switched back to dino oil in the Subaru, cleaned up the bottom of the car with Simple Green and did about 2 days worth of test drives. No oil leaks present and the garage floor is free of spots.

I love the idea of the synthetic, but I am switching all my vehicles back to standard oil.

I've run my 100000 miles 20 year old 911 with 0W-40 Mobil 1 and experienced no oil leaks. It seems that people have very different experiences with synthetic oil. Some experience leaks others don't. Currently I run Mobil 1 5W-50 which seems to work fine as well.

[MotoSook]

I'm not a materials engineer nor am I a chemical engineer, but I stayed at a Holiday Inn Express last week, and I have some experience with seals and how they behave in hydrocarbons.

The dino oil (even the viton seals to some degree) causes the seals to swell to varying degrees. So with a motor that has spent most of it's life with dino juice, a switch to Synthetic will likely leak or seep, as the seals will tend to "de-swell" without dino-oil.

I've seen seals in gas and oil applications that are a bugger to get out of their fitting because of the swelling (and that is with mostly gaseous H-C), a day or more later, the swelling is reduced. De-swelling will vary and the sealing due to the swelling would very too, right? So some of us can switch, others can't.

But why would you switch if your engine runs cool (normally cool) with dino-oil, and you change your oil on a regular basis? I run Mobil-1 in my Cherokee and Castrol 20/50 in the 911. I go 4500 or more miles on an oil change in the Jeep, and the 911 gets fresh oil sooner than 3000 miles..sometimes less than 300 miles because there is always something I have to do that requires draining the oil (!).

I don't worry about the Jeep on cold starts (Midwest cold mornings), and if I'm too busy to change the oil, I know it'll be good for a lot more miles. The Jeep had 18,000 miles on it when I bought it and it does not leak.

The 911 has over 70,000 miles on it and it leaks a little with 20/50 Castrol. Would I switch? Not until I have to rebuild the engine with all new seals. Even then, I don't think I would go synthetic since the 911 gets new fluids often enough, and I need something to do in the garage on a Saturday afternoons.

I've heard it said a couple times by difference sources, some directly connected to Mobil-1, that changing your oil at 3000 miles, with Mobil-1 is a waste of money, so you might as well run dino oil or run the synthetic oil longer. I don't think our 911's are exposed to extreme enough driving conditions that Mobil-1 will provide much of an advantage over dino oil. And we do change our oils on a very regular basis, right? RIGHT? If you are racing your 911..then it's a different discussion, but the discussion still may not fall in favor of synthetic.

The most important thing is that one chooses a good oil for the temperature range one's engine will see (ambient and normal engine temp), and change your oil regularly. Mobil-1 will not save your motor if you don't have a good preventative maintenance program.