Could someone suggest a product that would clean out a coolant recovery tank without harming/weakening the tank? I replaced my tank, but I hate to throw the old one away if it can be cleaned out. I thought it would make a spare or maybe someone could use it.

 

Numerous products for cleaning coolant systems on the shelf at the local auto parts stores but I just used soapy water. You aren't going to get all the year's accumulation of crud out with anything.

 

Mine was really clean? Just ran some water through it when I had it out to do the O2 sensor.

 

Jagcarver....are you referring to the pressurised expansion tank up near the rear of the engine, or are you referring to the coolant recovery tank situated under the left side front wheel arch?

Either way, just use a strong solution of dishwashing powder, fill it up and let it sit for an hour.
The expansion tank (the black one) you can get a small stiff bristle brush in there to give it a bit of a clean, then flush out.....this of course is done off the car ;o))
Be careful with the coolant low level sensor at the base of the tank.

Same applies to the Atmospheric Coolant Recovery Tank downstairs either insitu or preferably off the car....but to do that, you need to remove the font bumper ))

 

Crushed ice makes a good abrasive as well FYI

 

Thanks to all who replied. The new one was expensive, so I thought another member could use the old one if it would clean up. I didn't want to use anything too caustic that might weaken the tank.