If you were asked to purchase fairly-used vehicles for the company's use. What is the primary proof that the engine of a vehicle is still sound?

Their condition, suitability, present position, Engine-wise and others. If less expenditure involves in repairing then it is o.k.Preference and economical financial expenses incurred would have been to be taken into consideration.

Pretty much hard to find out but if I were you then, I would check whether I can detect or not white/bluish smoke from the exhaust at high RPM (in case of gasoline engine or black in case of diesel engine) .. This is indicative of oil presecence in the combustion chamber or incomplete combustion of fuel in the case of diesel.

 

In case you smell gasoline in the exhaust, lots of this means there's a problem in fuel injection/carbureuter/ fuel pump for gasoline...

 

Finally, there is nothing like exhausting an engine up-hill, you have to check and see.

 

Otherwise, you have to get a specialist with their tools :)

 

Good luck