can check your manual; often can find it printed on the oil fill cap as well

 

As for me it would be better to take Castrol 03102. It's just this engine oil, according to available data, is best suited for cars with quite serious mileage. When selecting the oil, you should also consider such issues, because if you take a simple classic, you can damage already worn parts. Drivers usually seldom make any rebranding of a car, therefore it is necessary to draw conclusions from what is. I can only say from myself that you will be able to study and choose the best oil for 5.3 vortec https://carfluidsexpert.com/best-oil...ge-5-3-vortec/ . As here it is painted in details which oil is better to use for this or that car. Technical specifications check with your necessarily and select from the available options. I came up with Castrol, and for your car may be better than anything else, there is a narrow individual situation. I hope that it will be useful for you.

 

I have bounced around oil brands for years, but always went with name brands like Pennzoil, Valvoline, and now Castrol High Mileage 5W30 which I use all the time now. The only problem is that by buying the large containers all they have is the synthetic blends. If you want high mileage oil that is strictly non-synthetic you have to buy the individual quarts which is much more expensive, so I stick with the blends for cost's sake. My front and rear seals leak so having a synthetic in there probably doesn't help, but non-synthetics mean more friction and wear at start ups I'm told. So all things considered, I simply use the Castrol High Mileage synthetic blend in the large bottles. At 245,000 miles it appears that I have done something right as far as oil selection. Other than a cracked head from an improper torque job following a head gasket replacement I have had no issues with the engine at all. Original trans with fluid flushes or filter change every 50,000 miles, and believe it or not, I'm still on my original starter. Funny thing about this truck is that just about everything I have replaced on it has a lifetime warranty, all on a truck that has not had a warranty in 14 years.

 

Much obliged for your recommendations. I'll take them into account. It's so difficult to choose one actually. Like, I know how cars function, how to repair them. But picking correct consumables is still difficult for me.

 

It will be better for you to use the help of professional car service because after the forum advice it could be only worse to your car

 

Guys, I find it difficult to choose a decent engine oil too. Like, there're many options and I don't wanna risk and try them on my own. What's your take on sites where you can read reviews on products? For example, I found a comparison of 5w30 or 10w30 and now I try to figure out if it's a trustworthy review or not.

 

I know this is a post from a couple of years ago, but I had to respond in case anyone else is considering a similar issue.
Unless you are experiencing a problem with what you are using, then stick with it. There is no BEST oil. Any of the name brand oils will suffice... changing it at the proper interval is much more important and it sounds like you have that covered. The correct weight for high mileage 5.3 is 5w-30.
However, if you want suggestions on oil brands you can find proper reviews on sites like thedrive, thecarslab etc.