Thread: Caltex Extended Life Coolant Concentrate for 300tdi?

I'd check the Caltex coolant before changing. Is it an OAT (organic Acid Technology) or ethylene glycol based coolant ? Coolant colour doesn't mean much now either. Green was good for older vehicles (ethylene glycol) but manufacturers dye OAT coolant any colour they like.

OAT isn't always suitable for older vehicles.
Have a read of this article..... Warning about engine coolant!!!!! - TR Register Forum

Search the net and it becomes very confusing. Ethylene glycol, propylene glycol, OAT (organic acid technology and IAT (inorganic acid technology) coolants are available. Modern vehicles are designed to use OAT or IAT but with an older vehicle you need to be very careful that it provides corrosion protection without damaging gaskets etc.

Now i am confused.

Originally Posted by DiscoMick

Now i am confused.

The 2-HEA additive in some OAT's softens some silicon based elastomers.
The Caltex coolant contains 2-HEA.

It's not a problem in a Tdi unless you use something like Hylomar to make/replace a gasket.

The only leaks I had in mine was from the original P gasket (replaced) then the replacement steel gasket when unthinkingly I dressed the new one with Hylomar and a leak from one of the oil cooler connections onto the radiator header tank as the radiator shop used the wrong size gasket after servicing the radiator.