Originally Posted By: electrolover
i really dont think just because they have 1 common ingredient makes them the same. i mean they all have water
They all have ethylene glycol (or in the case of Sierra propylene glycol)-but they are NOWHERE near the same! In the case of your '99 Mustang I would look very closely at the labels & stickers on the cooling system-some '99 Ford products came with the Orange/Dexcool type-they were supposed to only be Mercury Cougars, but my brother had a '99 Taurus that had labels for Orange on it, the previous owner had somebody put green in it, sludged EVERYTHING-fortunately he was able to backflush his heater core multiple times, also had IM gasket problems & 1 head gasket fail on the normally reliable 3.0 V6-at under 90,000 miles! So the right stuff makes a BIG difference!