Is Havotine (SP?) 5 years/100,000 miles safe to use on our cars ?
Thanks.

 

Yes, and recommended on an Infiniti forum. There is a catch though: the cooling system must be flushed and the old coolant completely removed first. (This is a good idea anyway every couple of years.) Final fill should be a mixture of AF and distilled water (to prevent corrosion).
Note: even the new AF formulas have to be replaced every few years.

 

what about the "safe" coolants (the propylene glycol versions)? they are supposed to be easier on the seals, and if you were to blow a head gasket, it is not supposed to mess up as badly as the other kind of coolant.

has anyone tried it out?

what is the preferred way to get rid of all the coolant? my friend said to buy one of the kits that splice into the heater hose, but i don't want to do that.

 

There's a petcock on the bottom of the radiator and a drain plug on the engine block. (I don't have a VQ engine, so check the owners manual for their location.) I would use Prestone coolant flush first. After draining, refill with plain water, run the engine up to operating temp, drain again and then fill with new coolant mix.