Ford has several different coolants and you must use the correct coolant in each engine, simply because every engine has a different combination of seals and plastic materials. The current situation is that you cannot even use a single coolant for an entire manufacturer’s lineup. And each company formulated their coolants to work with the types of metals, gaskets, and seals used in each particular engine. Others adopted a Hybrid Organic Acid Technology (HOAT). Honda came out with a blue low-silicate formula. But, running ANY engine when it’s low on organic acid type coolant cause form sludge.Īfter GM came out with Dex-Cool, ALL the car makers jumped onto the reformulation bandwagon.

The “rusting” usually NOT affect newer aluminum engines. When engines run low on coolant, the organic acid technologies oxidize and cause iron oxide deposits. But after a thorough investigation, it turns out that the only time sludge builds up is if the engine is low on coolant. Specifically, shops reported sludge buildup, especially in cast iron engines. Shops reported other problems with DexCool engines besides the 3.1 and 3.4-liter engine. So contrary to the ranting, DexCool IS the recommended coolant for GM engine. GM still uses Dex-Cool coolant and there is no longer a problem with gasket coolant interaction. GM has redesigned the gaskets that the problem has now been fixed. Everyone assumes the problem was Dex-Cool, when in fact, the problem was the type of gasket material combined with the use of Dex-Cool. So it’s true that DexCool caused gasket leaks, but the real problem was incompatibility between the plastic and the coolant. So if you don’t use new bolts and follow the torque directions TO THE LETTER, you’re going to get another leak.īottom line is that owners sued GM in a class action and won a settlement to reimburse them for the gasket failures. The problem with these gaskets is that they’re fairly low torque (because they’re plastic). At the time, many shop re-used the old intake manifold bolts with the new gaskets and then re-installed DexCool, only to see the gaskets fail again. The repair involves pulling the intake manifold and replacing the gaskets with a re-designed style. The problem was so extensive that it affects just about every 3.1 and 3.4-liter made in the late ‘90’1 and early 2000’s. For some reason (and NO ONE agrees on why this happens) the gasket material and Dex-Cool interact with one another, causing leaks. At the same time, GM also started using plastic intake manifold gaskets with a silicone bead around the ports. And, they gave it a 5-year, 100,000 mile lifespan. So GM switch to organic acid technology (OAT) and named that orange coolant Dex-Cool. You CANNOT mix coolants at all (More on that later> Well, history has proven that theory wrong. The old rule was that you could add the newer coolants to the old green stuff and all you did was reduce the life of the long-life coolant to that of the old green stuff. When car makers switched to aluminum engines and radiators and away from cast iron components, they also switched to long-life coolants. Plus, green coolant doesn’t have a long life-max 2-years or 24,000 miles. The problem with silicate is that it’s abrasive, so it’s tough on water pump seals. In other words, the silicate coats the metal parts to prevent electrolysis. In the case of the green coolants, the silicates deposit on metal surfaces to “PASSIVATE” them. But they also had additives to prevent corrosion. Their primary job was to prevent freezing. Most of the older green coolants were silicate based.

Dexcool coolant