I have always used Castrol GTX 5w20 but now they have 'With Trishield Technology'.

I am about to get my oil changed and I have Three bottles of Trishielf and One regular. Will it be ok to mix this together? Is the Trishield better?

 

I will be honest with you. Everyone always tell me that oil is oil. I disagree because it goes deeper than that, but as long as you have the same type of oil, ie. synthetic, blend, or conventional, you should be fine, just keep an eye on it is all.

 

None of them is Synthetic. How do I know its the same type?

 

It will say on the bottle which type of oil you are buying. If you mix the regular with the trishield you will be fine. I honestly dont see there being a problem.

 

None of them say Synthetic though and none of them is the high milieage type.

I am reaching 90K so should I be using the high mileage type?

 

engine oil is not like transmission fluid

engine oils can be mixed, synthetic conventional high mileage. no harm will be done

service centers recommend high mileage oil for cars over 75,000 miles


i run mobil 1 high mileage synthetic 5w-30

 

I heard you cannot mix the regular oil with Synthetic though.

 

My car is reaching 90K. Should I be using the high mileage that is for over 75K already? Any advantage?

 

it won't hurt a thing. I always use a qt. of Lucas oil stabilizer with all my oil changes. Or I will add a qt. of my diesel tractor oil(shell rotella oil). Why I do that is for dry starts keeps the cyl walls, pistons and pistons rings from ware when you start your engine. The oil is thinker and won’t all settle down to the oil pan. Keeps a nice coat on the cyl calls and the bottom of the pistons. But if you have a turbo DON'T DO THIS you WILL lock up your turbo (guess how I know)

 

yes it will help. High millage oil OR Lucas oil stabilizer will help with dry starts. The high millage oil has something like the Lucas oil stabilizer but not as much. Also with high millage I believe it uses a higher concentrate of detergent in the oil to help keep you engines insides clean since it has high millage. (but don't hold me to that’s one)