#Using hoat coolant in old cars plus

Do I take the risk of going all the way back to green? or a safer bet and use HOAT which seems like a reasonable compromise? I see that the Zerex OG is actually available in a 5 year formula. in order to prevent the 'jelling' of the coolant. So then it's down to how certain I am that every drop of Dexcool can come out of every nook and cranny in the engine, radiator, heater core, hoses, etc. It seems like many of the Dexcool problems have been with systems not designed for it.

#Using hoat coolant in old cars plus

Plus it was not designed for it as far as fluid flow and materials. From the reading I have done, and your inputs, it seems like the old-style Green was a fast acting antifreeze/coolant and that is why it needed to be changed every 2-3 years, while the newer OAT takes much long to be effective (the attached article said thousands of miles.) Well, I am talking about a 1966 Mustang that is only driven several hundreds of miles a year, so for that reason I am hesitant to keep it in the system. So my choices seem to be: keep the orange Dexcool, or use Zerex Original Green, Zerex G40 Si-OAT, G-05 HOAT, Prestone Yellow. Blue is, however, the most commonly used type of coolant in cars. White coolants are made from water, while black coolants are made from water and ethylene glycol. ethylene glycol and hydrocarbons are used to produce orange coolant, which is made up of ethylene glycol and hydrocarbons. As I see, it is a complicated issue with lots of opinions and real world experiences. It is a pale pink coolant made of propylene glycol and water. Thank you to everyone for your time to reply. To shows, Cars & Coffees, on nice weekends and it is stored over the winter (December through March) Take a middle of the road approach and put in a HOAT coolant which seems to be compatible with both the green IAT and the OAT/Dexcool coolants if not all of it is flushed out? Minimize the risk of congealing but maybe not eliminate it? Flush it out as best as I can and go with green and take a chance that not all of Dexcool is out of the system? Take a risk that it would congeal into jello? 3. Just stick with the Dexcool and don't worry about it? 2. Why did I want the older IAT type? Well I had heard and read a lot of bad things about Dexcool and all OAT coolants in systems not designed for them, and I figured that the safest bet would be the old-style green the car was engineered for. PHOSPHATED HOAT (P-HOAT) P-HOATs use organic acid technology and phosphates and have an extended service life. They are typically used by American (Ford, Chrysler) and European car manufacturers typically use them in their models. The shop filled it with a Dexcool OAT Havoline orange colored coolant when I asked for the IAT older type green. Some of the coolants from this range reach a service life of up to 10 years or 290,000 km. I had major work done to my 1966 Mustang powertrain Basically engine rebuild, new radiator, heater core, hoses, etc.