Overheating is also caused by cavitation of coolant in the engine. If the coolant can`t contact the water gallery walls then it can`t cool the engine. A friend of mine and gq owner was having this problem. One of the waterless cooling gurus told him to use their cleaner to clean the inside of his engine and then use their glycol product and it worked a treat. The inside of the cooling galleries get blocked over time a bit like cholesterol in your arteries.
Get rid of it and the heat transfer between fluid and engine gallery walls is restored.
Liquid intelligence was the company. They sell kits on Ebay for around $200ish.
As said my friends GQ with 2.8td, not renown for it`s cooling efficiency seems great now.
