Originally Posted By: mechanicx
You're wrong about Dexcool and don't have your facts straight but I see there's no point in arguing it with you. I know from experience that Dexcool and clones like AMAM aren't very tolerant of air in the cooling system. I'm not going to post pics of sludge cooling system to prove it to you.
My facts are perfectly fine. Yours however are misconstrued.
No cooling system is tolerant to air regardless of coolant type when the coolant is low. Rust will eventually form and washes into the coolant when the cooling system is topped off.
You are the one who shot out this claim...
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2492487#Post2492487
"Yes I've seen Prestone AMAM gum up within a few months in cap on radiator systems that did not gum on the FF Havoline formula."
You can't post pictures of your claim that Prestone AMAM gums up either because you can't prove your claim or because you are making an assumption it would happen based on some experience you had with Dexcool.
REGARDLESS, you need to stop making claims you cannot prove.
Originally Posted By: mechanicx
It wasn't coolant age or sealer tabs or electrolysis that caused all the issues seen. Electrolysis is exactly what the inhibitors are preventing and Dexcool's inhibitors doesn't deplete normally at the rate you are suggesting. It was primarily low coolant level and air causing the issues. Dexcool didn't cause issues on models with pressurised reservoirs but did on models that did not. They both had sealer tabs and it happened on problem vehicles within a few months of initial service.
Sigh. Now you are the one confusing stuff.
"Electrolysis is exactly what the inhibitors are preventing and Dexcool's inhibitors doesn't deplete normally at the rate you are suggesting."
Assuming no contamination? Probably but it is kind of silly to run it the advertised length. If going that long, the pH level needs to be checked. If the coolant goes acidic, it will corrode the cooling system even if the cooling system is properly filled. Here is a good article on this subject...
http://www.aa1car.com/library/cooling_system_electrolysis_corrosion.htm
The reason you see no issues in pressurized coolant tanks is because that is the only way to fill the cooling system. Therefore if the pressurized coolant tank is at the proper level then the rest of the cooling system is as well.
However on a radiator with a radiator cap and unpressurized over flow tank, the over flow can be at the proper level but the radiator can still be severely low on coolant. Both must be checked to ensure they are properly filled.
Air is not magically turning coolant into gum in the over flow tank as you keep suggesting.
Originally Posted By: mechanicx
None of the automakers recommend Dexcool/Dexclone in their cooling systems that were not validated for it because Dexcool is not a universal formula that you think it is. Why do you think GM and Ford use pressurized reservoirs while switching over to Dexcool formula? It is basically a necessity.
OAT is the universal formula for cars and light-duty trucks. Ford is now going to it. Other will follow. Just wait and see.
Prestone AMAM, Super Tech, Peak Long Life, and Polar Long Life are ALL OAT coolants ALL stating they work in ALL MAKES and MODELS (for cars and light-duty trucks) using ingredients similar to Dexcool and have been out for many years now.
Polar Long Life says right on the label, "Mix with ANY color antifreeze including GM Dex-Cool, Ford & Chrysler"...
http://s1238.photobucket.com/albums/ff48...12-20144835.jpg
The creation of pressurized coolant tanks wasn't due to Dexcool. Chrysler and Ford have been using pressurized tanks in numerous vehicles starting around the mid-90s when they were still running green in everything. It is simply a progression of technology.
Originally Posted By: mechanicx
Prestone and the rest of the Dexcool coolants prevent corrosion very well and easily for the 5 year service interval. But the cooling system has to remain completely full and in good working order. It's not something I will put in just any person's car who may allow their coolant level to run low.
A lot can happen to coolant in 5 years. Draining and refilling the radiator and tank at least every two years is good preventative maintenance. Doing so keeps the coolant fresh, helps gets rid of sediment in the radiator, and also gets rid of the need to due a full blown flush. Even though it is claimed different coolants can be mixed, I would never recommend mixing the old green stuff with any OAT or HOAT coolant.