Coolant System Flush

[John Kuzman]

My next BJ7 winter project is to tackle a long overdue flushing of the coolant system. The system is flowing fine, I just think it is time to flush and re-fill with a fresh mixture.I am planning on replacing the radiator hoses and cleaning up some crud on the thermostat housing at the same time. Can anyone provide some advise on the best way to flush the block? I thought of a traditional reverse flush using a tee in the heater hose, but I do not want to run the risk of dislodging any build up and creating a blockage problem or damaging the water pump or heater core with a reverse flush. Any advice and Do's-and Dont's would be greatly appreciated.

 

[Dave Russell]

If you don't want to dislodge anything - which is usually the reason for flushing - just open the drain taps & trickle some fresh water through from the top.The only good way to clean a block is to hot tank it & scrape/scoop/flush the rust out through the removed core plugs.

A real reverse flush is usually done by applying compressed air plus water to the engine side of the top hose (thermostat removed & heater bypassed) & letting the junk dump out of the top radiator connection where the hose was connected. Probably as you say, it just moves most of the stuff to a more troublesome spot. The best way is to do the radiator (bottom to top) completely separate from the engine & I don't think that this removes much of the real plugging.

I personally think that flushing doesn't really accomplish much except to get the old coolant out.
So either just drain & replace coolant or have a radiator shop do a complete chemical clean of the radiator.
D

[ 01-14-2004: Message edited by: Dave Russell ]</p>