Quandary
Well-Known Member
Just been doing this today and a slow and messy job it turned out to be, so I thought it might help if I posted some hints in case anyone else is about to tackle it.
The book recommends draining through the cock on the engine and also by the heat exchanger output at the back, flushing by squirting a hose in the inlet to the heat exchanger. The engine drain cock is plastic and located close to the oil filter and behind the dipstick riser where you can not easily turn it, it is not hexagonal and you can't get plumbers pliers on it. My solution was to thread a 3/4 " box spanner over a short length of flexible hose and jam it over the cock lugs so that the cock could be turned on and off with the drain hose connected. The hose you need is about 10 mm so ordinary garden hose is too big. An alternative to the box spanner is to use a jubilee clip on the drain hose so that you can use the hose to turn the cock on and off. The cock is low so if you have a tall container or even a bucket to catch the water it will not drain, however an old squat 10 l. paint tub just about does the job and has the advantage that its white so you can see the colour of the discharge. My boat has a H.W. system so rather than disconnecting at the outlet from the heat exchanger it was easier to disconnect the return from the calorifier, but after flushing this for a while it was reconnected while I continued flushing through the header tank and drain cock. The idea of squirting a hose in the front of the heat exchanger is crazy, the hole is about 16 mm dia. and the water comes back every where. I had a plastic Hozelock tapered jet terminal and filed a bit more off the taper too jam it in but had to hold it firmly in place. You really need a second bod. on hand to turn the hose on and off, but you and the boat will soon get wet. The translucent plastic header tank had an internal coating of brown rust but it is easy to disconnect and remove the tank and then flush and wash it under a strong hose, I immersed it in a bucket of hot water and detergent and kept shaking until I could see through the plastic again. The water coming out when flushing was clear almost straight away but then when I topped up with some clean water and ran the engine for ten minutes it was dark brown so I repeated this process adding water through the header a few times as I fancied having clear coolant for a week or two. I filled with a 50/50 (garage bought) ethylene glycol/water mix, the header was up to the marks with only about 3/4 of the quantity added but when I ran the engine it dropped. I will check and top up again tomorrow. I took the first bucket of coolant home while I find a way to dispose of it but the copious quantities of water used for flushing thereafter was tipped in the canal.
The job which in the book looked easy (and would be on a bench in a workshop) took half a day, with rusty water well distributed on me and around the boat though quite a bit of the time was spent finding or making the bits needed.
The book recommends draining through the cock on the engine and also by the heat exchanger output at the back, flushing by squirting a hose in the inlet to the heat exchanger. The engine drain cock is plastic and located close to the oil filter and behind the dipstick riser where you can not easily turn it, it is not hexagonal and you can't get plumbers pliers on it. My solution was to thread a 3/4 " box spanner over a short length of flexible hose and jam it over the cock lugs so that the cock could be turned on and off with the drain hose connected. The hose you need is about 10 mm so ordinary garden hose is too big. An alternative to the box spanner is to use a jubilee clip on the drain hose so that you can use the hose to turn the cock on and off. The cock is low so if you have a tall container or even a bucket to catch the water it will not drain, however an old squat 10 l. paint tub just about does the job and has the advantage that its white so you can see the colour of the discharge. My boat has a H.W. system so rather than disconnecting at the outlet from the heat exchanger it was easier to disconnect the return from the calorifier, but after flushing this for a while it was reconnected while I continued flushing through the header tank and drain cock. The idea of squirting a hose in the front of the heat exchanger is crazy, the hole is about 16 mm dia. and the water comes back every where. I had a plastic Hozelock tapered jet terminal and filed a bit more off the taper too jam it in but had to hold it firmly in place. You really need a second bod. on hand to turn the hose on and off, but you and the boat will soon get wet. The translucent plastic header tank had an internal coating of brown rust but it is easy to disconnect and remove the tank and then flush and wash it under a strong hose, I immersed it in a bucket of hot water and detergent and kept shaking until I could see through the plastic again. The water coming out when flushing was clear almost straight away but then when I topped up with some clean water and ran the engine for ten minutes it was dark brown so I repeated this process adding water through the header a few times as I fancied having clear coolant for a week or two. I filled with a 50/50 (garage bought) ethylene glycol/water mix, the header was up to the marks with only about 3/4 of the quantity added but when I ran the engine it dropped. I will check and top up again tomorrow. I took the first bucket of coolant home while I find a way to dispose of it but the copious quantities of water used for flushing thereafter was tipped in the canal.
The job which in the book looked easy (and would be on a bench in a workshop) took half a day, with rusty water well distributed on me and around the boat though quite a bit of the time was spent finding or making the bits needed.
