Ethylene Glycol anti-freeze

theLearner_3

Stephen_Leak wrote: »

Reverse flushing is dead easy.

Obviously, drain the system either the "proper" way by taking off the under radiator shield and undoing the drain tap, or the "easy" way by just taking off the radiator bottom hose. You need the hose off to flush the system anyway.

Turn the heater to hot, to open the valves to the heater. Take the cap off the expansion tank. Shove a garden hose into the bottom of the radiator. Seal it as best you can with an old rag. Turn on the tap. When clean water is coming out the top of the expansion tank, job done.

The brown colour is rust. With the anti-corrosion additives in the anti-freeze and if it has been changed every 2 or 3 years, it shouldn't be brown enough to mask the identification dye colour, though.

You have to be very careful with all the types of anti-freeze available nowadays. The new red/orange Organic Acid Technology stuff can do all sorts of nasty things to your engine's "innards" if mixed - even in small quantities - with the old blue/green ethylene glycol stuff. If changing between these two types, flushing the system is a must. However, there is now an even newer OAT stuff available - blue/green and purple - which can be safely used as replacements for both other types without flushing.

thanks for going through this - will this just flush out the radiator? and what about the engine itself - does this need flushing as well?

anewman

theLearner wrote: »

thanks for going through this - will this just flush out the radiator? and what about the engine itself - does this need flushing as well?

As I understand it doing this flushes the whole system, which is why you should put the switch inside the car onto full heat so that the heater matrix radiator thingy gets some of the flow of water to clear it out.

Stephen_Leak

Conor wrote: »

Just a point:

MAKE SURE THAT YOU DONT BUY THE STUFF THAT IS PRE-MIXED. Basically you're paying for 2.5 litres of water because it's the same price, and sometimes more, than the stuff you dilute yourself.

A good point. Slightly off topic, but they also do the same trick with windscreen washer additive. 5 litres, concentrated, Woolies, half price at £1.99!