Question for all the oil experts in this forum. Tried a search and read the oil journals but came up with nothing. So here goes.

Im running synthetic right now but planning to change the oil before putting the S in storage (4-5 months) for the winter. Is it safe to switch back to mineral/regular oil just for the winter storage then back to synthetic in the spring? Dont plan on starting the car at all until the spring and then drive straight to the shop change the oil right away. I think it would be a waste of money to use synthetic oil during the storage period.

Any thoughts?

 

For what you're doing, put the cheapest, generic oil you can find. Just make sure it's got the proper API rating. It just doesn't matter for the months it's sitting in there or for the few dozen miles you'll put on it in the spring. Switching back and forth between synthetic and non is no big deal. You just don't want to go from non-synthetic to synthetic on an older engine that has already developed leaks.

 

Thanks xviper.

By API rating, do you mean the "For Gasoline Engines Certified" seal?

 

...or is it better to keep the synthetic (Mobil1) with only 2000 km run on it and change it out in the spring.

 

And "SJ" or better.

With that few miles on it, just keep it. Dump it in the spring.

 

The real concern here would be leaving old oxidized oil in the engine while in storage. The fresher the oil the better. In fact, if it were me, I'd just put in the same good quality fresh synthetic oil in for storage. Unless you periodically start your car or take a short trip around the block during the winter, I don't know why that synthetic wouldn't be good to go when you bring it out of storage 6 months later. Is there something else that would cause the synthetic oil to oxidize and breakdown other than running the engine for short periods of time?

 

The instant you open the oil bottle, oxidation continues. Heat and combustion will accelerate that process. The only thing that might be of mild concern would be the pH of the oil, but then, after a few days, it's just sitting in the bottom of the oilpan where a slightly acidic pH won't do much harm.
Remember, the new '06 can have it's oil stay put for up to 12 months if the oil minder hasn't given its indication. I don't think a few months storage will have any detrimental effects.

 

One thing to do before you store your vehicle that I think is just as important as changing your oil is putting fuel stabilizer in the last tank of gas that you use. Then drive it down to as low a tank level as you feel comfortable before storage. You can buy the stuff at any autoparts store.

 

Store it with the tank full. Anything less and condensation will form in the tank, possibly causing rust.

I run Mobil 1 and change it once a year, right before I store it. I've been putting fresh oil in my cars before winter storage and then driving on that oil come spring since 1979. Never had a problem.

 

[QUOTE=Conedodger,Sep 9 2006, 07:05 AM] Store it with the tank full.