I was at the gas station today picking up a bottle of coolant (my water pump is on the fritz!). I noticed a jug of anti freeze marked as "Heavy Duty" and it looks like the liquid is not the usual flourescent green but purple. The station attendant says that its made for deisel cars. First I've heard of it! Anyways, aren't coolants all the same? Does deisel engines have a special blend of coolant that they use? My husband's H1 uses the regular green fluid. Can someone please enlighten me! Thanks y'all!