Quoting: Roadkill
How long did you run it for with soda in ?
I cant remember not to long though as that stuff fizzes and presure builds up
just found this
Before you add fresh coolant, it should be a good idea to flush out the radiator. There are any number of brands selling a radiator wash. A good home recipe is caustic soda. It is easily available but use it with caution. It will cause irritation to the skin. Dissolve the caustic soda in a plastic mug of hot water. It will fizzle and splash. Exercise caution. Drain some water from the radiator and add the caustic soda solution. Refit the radiator cap. Now go for a drive. This means running the engine for 15-20 minutes. As the caustic soda circulates through the radiator and engine block, it will dissolve rust residue and any other dirt.
Back home, you should drain the water. Remove the radiator cap with care. The liquid is under pressure and will shoot out. The temperature could be well above 100° C.
Wash the radiator with cool water — your garden hose is ideal for this purpose. As the water drains out, keep filling the radiator with the engine running. Go on with it till clean water starts flowing from the radiator drain plug. Stop adding water but keep the engine idling till all the water has been drained. Switch off the engine and close the drain plug.
Now add the coolant/anti-freeze and top up with water. The engine should be idling. Please note, the water should be of high quality. I use distilled water which has no minerals or other impurities. The tap water you use may be dirty — even if you can’t see the dirt and impurities. This will surely clog up the radiator. Regardless of the coolant, this will cause the engine to heat up.
