under severe duty driving, when to flush / change antifreeze

 

 

Ok....I do a lot of driving, city with stop & go driving got 70,000 miles on in 18 mths....will change it now rather than wait...cost is not an issue, like some operators I know who never bother to change according to their usage, instead , they rely on manuals / word of mouth / bad advise from bad shops.....last week, a operator, 3.5 V6 engine, who had only 135,000 miles, had engine lite come on, went to shop...all they did was reset the light, all else was ok..??..next day light came on again, back to shop, barely made it...overheated on the way, turns out, Rad fluid was low, overheated, head gasket problem / leaked into engine...POW, no more engine > $4,000 for used replacement....live & learn I guess, thx for reply, cheers