[hotbryan333]

Based on viscosity ratings alone, there is no difference until the outside temperature drops to the point where the oil starts to thicken up. What that temperature actually is will depend on the kind of oil he used. For the better dino oils, that's somewhere around 20 F degrees below freezing. For the better pure synthetics, that can be close to 60 F degrees below freezing.

But who knows what the dealer used.

Well i have been using Full synthetic and opted out for regular dealer oil change because of the price difference, and i did not see any real difference in performance or gas mileage other than possible better protection that i am not going to see unless i keep the car for 150K miles.

The dealer said API is more important than the rating, so i feel safe now since 10w-30 is also recommended.. The dealer used Kendall 10w-30 conventional oil, i am out of free oil change, so i will just take it to the firestone, since they have 19.99 oil change + they use synthetic blend.... so thats my plan

Thanks all

 

[hotbryan333]

I just check the oil, and its little low,

Is it okay to add full synthetic to regular oil? I meant 5w30 fully synthetic interchangable with 10w-30 conventional motor oil?

I need to add about half a quart, but all i have is full synthetic.

Help experts

 

[hotbryan333]

There a two basic kinds of synthetics, ester and PAO based. You should avoid mixing them. After market oil companies state it is OK to mix oils, but it is possible to end up with a combination that turns to tar. Lots of people mix oils with no problem. Some people aren't so lucky.

If your engine is clean inside, and old oil is in relatively good condition, there shouldn't be a problem. If your engine is really gunked up, stay away from synthetics, they can loosen up the gunk and clog oil filter or oil passageways.

Well, i have been using full synthetic oil until around 55k, and switch back to dealer conventional oil, and he put 10w-30 conventional oil, and i am trying to add a quart, and i only have fully synthetic penzoil 5w-30.

I assume my engine is pretty clean, since i regularly change the oil between 4k to 5k

 

[hotbryan333]

It's complete and utter BS that "thicker" is better in the winter. If I were the manager of that dealership and heard one of my techs say that, I'd fire them on the spot.

The colder the outside temperature, the thicker the oil gets. Knowing first hand living in Canada, conventional motor oil, if neglected, will have a viscosity of molasses under extreme cold conditions.

Having said that, you should be okay if you live in a warmer climate, but your engine performance will suffer a bit. If you live in a colder climate, all I have to say is good luck. Unless you can switch back to the actual recommended engine oil of 5W30, it's pretty risky to run on a slightly thicker viscosity.

It was actually the manager that confirmed those facts lol

I guess i will avoid this dealership.

Is it okay to go down to 0w-20 synthetic in our car? So it will save more fuel?