Hello everyone,
About 7 years ago I flushed out the green coolant in my 1991 Chevy K1500 pickup with a 4.3 V6. The truck now has about 97,000 miles on it. Normally, I would say stick with whatever coolant came from the factory but the orange coolant seemed like a better choice at the time. I liked the fact that it had a 5 year or 100,000 mile life, and the container said that it was easier on water pumps. It was also ethylene glycol based and seemed to be very similar to the green coolant so I figured why not try it. After flushing the green coolant out, I replaced it with the orange coolant (I think it was texaco) and mixed with distilled water.
My water pump recently started leaking, I don't think it was the orange coolant, just age. I have not had any other problems with the cooling system, but I have recently heard some bad stories about the orange coolant causing head gasket damage, intake gasket damage, and water pump damage, on some vehicles. I've also heard stories about the orange coolant "sludging up" but I have not noticed that problem yet. On the back of dexcool containers, it says the coolant is for use with
1994 or newer vehicles and that on some vehicles (mine was not listed) if you did not change the coolant at least every 2 years, cooling system damage could result.
I'm going to flush the system & replace the water pump, upper and lower radiator hoses, thermostat, and radiator cap. Should I keep using the orange coolant or go back to the green coolant ? I would stay with the orange if I new it would not hurt anything, otherwise in the absence of an answer, I am inclined to go back to the green stuff, providing it won't do more harm than good.
I'm not sure why GM specifies 1994 or newer vehicles and I tend to wonder what the difference would be between a 1994 4.3 V6 & a 1991 4.3 V6 ? Are the seals or metals used different ? That's about the only think I could think of that would make a difference.
Is there anyone out there from a GM service department that knows the answer ? I'm hoping a mechanic or GM tech may be able to answer this question with a reasonable degree of certainty.
Thanks for your help. John