How do I ensure antifreeze has got to all parts of block and thermostat has opened.Do I have to run engine for some time?.Can I remove thermostat and pour mixture in or is draining down sufficient anyway.Any help gratefully received.
Last two seasons I have flushed fresh water through the system by removing the pipe from the skin fitting and putting it into a bucket of water on cabin sole (not directly from the hose pipe ) after the engine has run for a short time I have put pick up pipe directly into neat antifreeze and stopped engine when the exhaust water changes colour had no probs at all with this system.
1. Flush with fresh water as described by "pete"
2. Take the thermostat out (so I can check that it's still working and clean it - it's usually quite grotty)
3. Block the inlet hose
4. Detatch the exhaust injector hose
5. Fill it (via the exhaust injector hose) with a strong anti-freeze mixture (it's been suggested that neat AF will rot hoses so I dilute it to cover down to about minus 20).
you didnt say if your engine is freshwater or raw water cooled? but you mention drain down so Im guessing its raw water
If its raw water cooled, just flush it through with fresh water and open the draincock on the side of the engine. No water at all is better than guessing the strength of antifreeze you need. Yes you do need to run the engine until it gets to operating temperature. But make sure that the water level in the bucket is well below the water injection point into the exhaust!
The only point in putting antifreeze through the engine is if it has an inhibitor in it ..and not all do!
And the engine is going to be half empty anyway, it will drain back to what ever water level you have in your bucket when you stop the engine..better to leave it completely empty!