They want the engines to go down quicker, so most people replace their cars more often. I know my family did, our suzuki cars had cng too, compared to petrol engines which run at 90-120C, cng always runs on between 105-120C, therefore our cars engnes needed rebuilds at 70-80,000(before we got tired and finally made the jump to honda, cause we heard they were more reliable). A lot of mechanics also tell us to pour water instead of coolant cause they make the most money from engine rebuilds and overhauling.That's also why our awaam thinks that cng destroys the engine and started avoiding it, it's not the cng, its the putting water in the radiator that destroys your engine. CNG is harmless as long as you're putting coolant in the radiator. I don't know about their recent cars, but uptil 2010, they were doing it. Our family has had 2 fx's, 2 mehrans,(1987 and 2005 model) and one alto 2010 model, all had water in the radiator. In brazil, cng use is widespread and there are no complaints of cng engines dying quicker, because they put coolant in the radiator.
