Well then you should change your oil between 2000-2500 km coz Qaim's oil filter are totally 3rd grade quality filters i have used them.
2ndly Delo gold is not a good oil and it should be changed after 2000 km coz this oil is now made is pak.
Now if you are going for thermostat valve then you have to take extra care of it, coz after installing thermostat valve drive your SUV on simple water no coolant for atleast a week and daily check the water level in radiator so if there is any old hose pipe it will worn out and you will know.
About average check if your SUV throwing excessive smoke, if it is throwing excessive smoke then get your diesel valve checked, and ask the mechanic to close the diesel a little bit.
These tips are for you.... Otherwise a good mechanic will know what you are talking about.
If you need anything else let me know....
or you can reach me at 0344-5512155