Coolant Flush

[SwA6]

From what I read about people doing this, they simply take off the lower radiator hose and let the fluid run out, fill it with distilled water, run the engine for a little bit, and repeat the process until water starts coming out of the radiator hose. The Bentley manual is a little more complicated than this. Is this really a legit method of doing the coolant flush? It also talks about putting on VAG 1274/8 and /10 on the expansion reservoir but doesn't say to use VAG 1274B to keep the system pressurized. Can anyone clue on if you actually need to order these parts or is it a waste of time and money?

[Joby]

Well, first off, you should have replaced the coolant at the last t-belt service. G-12 is probably good for at least 30,000 miles. But, with that being said, what's the recommended Audi service interval for coolant? I'd spend the eight bucks and get a specific gravity tester for the coolant. If you don't have good frost protection, replace it. Pep Boys and any other auto store will probably take you old coolant for free. And you probably only need two gallons of 50/50 coolant/distilled water mix to get back to good standing with the Audi gods. G-12 is about 25 bucks, with tax in most states. I think it's good insurance against problems in your system, later. Distilled water is like a buck twenty at your local grocers.

[Joby]

Also, The procedure outlined in Bentley is overdone. Once you drain the system, you only have to be sure to bleed the air out, typically at the highest point in the system. Usually the heater core weep hole. Not difficult at all.

[Prospeeder]

G12 is actually good for an entire T-Belt w/p service interval. Roughly 100k miles. If you had a t-belt done recently, dont worry about it. If the coolant is old enough to be worried about its probably due for a belt and waterpump service.