Mister Quickie

I've been topping off with the recommended Mobil 1 0W-40. When the dealer changes the oil they use Pennzoil.

For purposes of topping off a half quart here and there in between oil changes I have some old Safeway "SAE 30 HD" quarts lying around. Are those good enough for topping off purposes or should I stick to the recommended Mobil 1 0W-40?

(I don't track the car but I take it to 6/6500 RPMs every other day or so ...

DaveSpeed

Go buy a quart of whatever the dealer is using!

nick49

I think you'll be fine. Any automotive motor oil made over the last several years, whether paraffin based or synthetic will mix perfectly well with any other. I make my own blend for some of my motorcycles. I don't want to run a pure synthetic. I also would pour a quart of paraffin motorcycle oil, with ZDDP in with the synthetic oil in my 996 C2 when doing a change. A bit of added protection.

Macster

All I can really offer is what the factory says: When topping up it is preferred that the same oil used to fill the engine be used but if necessary any approved oil can be used to top up the low oil level.

I would add a comment that unless the oil level is low, dangerously low and you have no choice I'd never use some old Safeway (or new Safeway) HD 30 oil. Then I would as soon as I could have the oil changed and write on the blackboard 100 times "I will never ever never ever drive my car and not have a spare bottle of <name of the oil used to fill the engine> in the car."

Make that 200 hundred times.

Porsche says that non-approved oils are not miscible with approved oils and therefore I would take this to mean stay the heck away from non-approved oils for even topping up.

There is no excuse to be caught out with low oil level and no spare bottle of oil the same brand/type used to fill the engine the last oil/filter service.

Come on people, what's wrong with you? Do you burn damp leaves in your nice home's fireplace when you run out of real fire wood? Use dried cow dung patties for the fire to cook the shrimps on the barbie when the bag of mesquite charcoal is empty? Drink light beer when out of a fine single malt Scotch?

Geez. You're driving a fine sports car not some riding lawnmower.

Sincerely,

Macster.

dennis hiip

Yes, nearly all oils are compatible with each other and mix with no problems, but not always. My mechanic buddy tells the story of mixing together 2 oils and creating a mess. I'd only do it in an emergency.

Invius

I take offense to what Macster says!!! I drink Scotch AND light beer (although not simultaneously). Also a bourbon drinker if the mood strikes.

jdog

All I can say is that once when the oil was low in my F150 I added some 30wt oil and the engine started to make a ticking noise on start up. When I drained and added all the same weight. No issues. Could have been coincidence though. No factual proof.