Coolant Flush Chemicals

[JMI]

Prior to a coolant change is a flush with commercial flush product, run for a day or two, a good idea? Charged my system with the pricey BMW blue stuff today and prior to adding it did a couple of flushes with plain water. Noticed what looks like rust in a thin coat inside the expansion tank. Didn't get it out with the plain water flush.
Is there a recommended flush product?

TIA

[632 Regal]

I wouldnt and I dont think it's reccomended.

[Blitzkrieg Bob]

Citric or Phosphate, so leaving them in too long can go beyond cleaning, and start disolving the rad, head and that tender head gasket.

Plus I don't think it will get the stains out of the plastic anyway.

Try an old bottle brush.

[joshua43214]

Don't worry about the discoloration of the tank. Don't use a flush unless the system is contaminated with oil and even not then if possible.

if it REALLY bothers you, and you don't want to buy a new bottle to brighten the engine bay, dig arround for the Porshe service bulitin on removeing oil contamination from cooling systems. It will return the system to like new cleanliness, Takes all day for a professional, does not cost much, is scary as hell to do, gives you more bragging rights, and will not harm Porsche cooling system if done properly. Of course you drive a BMW....

[Gene in NC]

See Gale post on this board.