What is the best engine oil for H2 ?
 

I have a 2005 H2

Mileage \ 130.000 miles

from one year ago I started to use 20w50 oil

Oil pressure is good @ 40

GM Recommended oil is 5W30

My Question :

Is it normal & safe to use 5W30 or 10w40 after 130000 miles & After one year of using 20w50 ? :)

I live in a hot area :(

We are now in the winter And I began to hear sound like tic tic tic tic When I run the car in morning & Stay until the engine heats up then the sound disappears :(

I locate the sound from the last nail of the exhaust (( The nearest one to the driver ))

Is It the engine valves ?

If it is the engine valves, Is it possible that if I change the oil from 20w50 disappears?

Mineral, partly synthetic or 100% synthetic oil did you used ?
viscosity charts are different depending of type of oil that you use.
but for the commun brand, 20 will go as low as freezing point, why not use 5w55 if you wont the protection for high temp and cold protection ?
and yes it will probably remove the noise, and use new 100% synthetic oil, use a flush fluid that you mix whit your old oil before draining it.

20W50? Awfully thick! Probably responsible for the ticking noise because it is too thick. I use 5W30 Mobil One extended mileage full synthetic. If you are worried about heat then perform a coolant flush and change your thermostat. I would run BG engine flush in your current oil per instructions then change out the oil asap.

Do not use 50 weight oil! Unless you plan to warm it up to 200 degrees before you turn over the engine.

What do you think about mobil-1 0w40 full synthetic ?

WHy not just follow the vehicle's specifications?

Because the previous user was using 20w50 for a long time

The previous user was wrong for using that oil... The engine was designed for a particular oil weight and I don't know how it survived for so long. If it is running fine now i.e. not adding oil, spark plugs are fine etc... that I personally would count my blessings and use the correct oil. The engine was designed to operate in most temperatures BUT with the correct oil. Can't say it any clearer than that... Good luck with your decision.

Thank you for your cooperation Man1nboat

You are very welcome Ahmad! Many here have bailed me out too!