Modify Bilge Pump To Drain Coolant System?

[Rendelf]

Hi peeps. Some advice needed please.

 

I'm in the midst of the first full service our Isuzu 42. I'm endeavouring to do it all, and to do it properly, as the previous owners seem to have done nothing. Ever!

 

I need to drain the coolant from the system, as it certainly hasn't been done for three or more years.

 

The tank on the swim has two hoses, but both are at the top, at either end. (I'd have thought that one would be at the bottom, from what I've read here.) There is no obvious drainage point, but quite a few bleed valves.

 

There is also a calorifier circuit.

 

We are trying to not spend lots of cash, so I can see three options:

 

The brass hand pump that's set up for pumping oil from the sump.

Modify an old bilge pump that I have recently replaced.

Use the engine's coolant pump to push everything out.

 

 

The bilge is clearly the better solution, in terms of time and energy. I figure I can dismantle it, and then attach an intake hose, which can be placed into the keel tank/radiator, once the top half of the system has been drained (either by gravity or by the pump.)

 

If I were to use the engine pump, I imagine I'd disconnect the hose that sends coolant into the engine. The problem I can foresee is that the pump might need to be primed, or might be damaged by pumping air? I don't think that the engine could be damaged by such a short run... but am uncertain.

 

The brass hand pump would be laborious, and also, I would have to find a way of fitting a tube to the thread at its base.

 

 

In any of these scenarios, I would of course store the coolant in a suitable container, and dispose of it properly.

 

Thanks for suggestions!

 

 

 

[nicknorman]

Almost certainly, one of the tank connections will have a pipe that goes down to the bottom, inside the tank. I would certainly hope so anyway!

 

Bilge pumps are normally centrifugal type which are reasonably good at pushing but very bad at sucking, and totally hopeless at sucking air. I think you would up find it impossible to get it going unless you installed a foot valve (one way valve) at the far end of the hose you are going to insert into the tank and fully primed it, which even then would be difficult.

 

What you need is a diaphragm type pump as per Whale Gulper. Lots of folk have this type of pump on their showers etc. you can tell, because it works in gulps / spurts, rather than continuously. So unless your bilge pump is a diaphragm type, I suggest getting hold of a Gulper type, perhaps "borrowing" it from your shower if it has such a pump.

 

The engine pump is also centrifugal and will be completely ineffective at pumping air into a tank full of water so as to get the water out, or sucking on air to do likewise.

 

Otherwise, it's the hand pump and a bowl of shreddies!

[ditchcrawler]

If however one of the pipes doesn't run to the bottom you will need a dip tube that you can push to the bottom, you may even be able to siphon it into a bucket stood in the bilge. So maybe nothing more than a long length of plastic pipe the will poke down to the bottom of the tank and also reach the bottom of the bilge.

[nicknorman]

If however one of the pipes doesn't run to the bottom you will need a dip tube that you can push to the bottom, you may even be able to siphon it into a bucket stood in the bilge. So maybe nothing more than a long length of plastic pipe the will poke down to the bottom of the tank and also reach the bottom of the bilge.

Yes siphoning is a good idea, although if it's anything like our tank it will go right to the bottom of the boat so you would be unable to get the last bit out, but you should certainly be able to get most of it out.

[Rendelf]

Thanks for your help..

 

I don't really like shreddies, even with fresh, cold milk... multi-year-old glycol doesn't sound very nice!

 

We do have a diaphragm pump for the shower... it may be interesting to discover which process (hand pumping or removing, using, and reattaching) takes a longer time.

 

If I were to syphon.... I'd rather not drink the stuff. Though, I do like alcohol, sugar, and defunct rust inhibitors. I could perhaps place a rag in the pipe and pull it out with a string to initiate?

 

Nick's right though, the bottom of the tank is at the same level as the bilge. I suppose a little bit of coolant won't hurt though. I'm not changing coolant colour.

 

The calorifier is another point... I'm pretty sure that the bottom of that circuit is roughly the same level as the pump on the engine, but decidedly above the keel tank... so, gravity alone wouldn't drain it? I expect I'd have to disconnect its hoses, and then bleed air from the system once filled?

[ditchcrawler]

Thanks for your help..

 

 

 

The calorifier is another point... I'm pretty sure that the bottom of that circuit is roughly the same level as the pump on the engine, but decidedly above the keel tank... so, gravity alone wouldn't drain it? I expect I'd have to disconnect its hoses, and then bleed air from the system once filled?

I would have thought that as the system empties air would be free to enter the calorifer coil by the upper pipe work as the coolant flowed out of the lower one

[BargeeSpud]

If you have access to 240V, then a wet/dry vacuum will suck your bilges dry & take any muck with it too. Emptying might be an issue if the water is oily. I had a go with one on my engine tray & sucked up a lot more (5 gallons estimated) than I thought was in it! With the help of a little bit of Gunk, I did the rest of the bilges whilst I was at it, much easier & quicker than a hand pump, plus you can hire them quite easily if there isn't one immediately handy.

 

Have fun!

 

P.S. In case you're wondering about the humungeous amount of water in my engine tray, I did have a leak from the water pump at the time & it took that lng to get it sorted because I was having to run & top up the engine daily.

[cuthound]

Also don't underestimate the quantity of engine coolant, and if your doing it at the same time, the water contained in the radiators and boiler circuit.

 

When I changed mine (40 litres of engine coolant and 25 litres of heating circuit) I used a 12 volt pump from Machine Mart, about £35 if I recall correctly.

 

I also used Ford's 10 year Prestige antifreeze, costs a bit more but won't need changing again until 2024

[ditchcrawler]

If you are not using ready mixed it is advisable to use deionised water for the 50/50 mix

[system 4-50]

Invest in a Pela. It is a really useful device.

[blackrose]

You need something reasonably powerful to get the coolant out as well as what's in coils of a calorifier (if there's one in the system). I'm not sure a bilge pump would do it? I used a wet/dry vac on mains. Took about 20 seconds.

[Rendelf]

If you are not using ready mixed it is advisable to use deionised water for the 50/50 mix

Thanks for this... My plan has been a 33.3/67.7 mix as we're on the south of England. Would using deionized water help inhibit corrosion?

 

As we're often between places, I've ordered a Pela; seems a sensible thing to own. It also solves the broken brass sump pump issue, and should help me drain the dregs of the water tank for re coating. (That's a job I'm looking forward to)

 

As for wet/dry vacs...would it be crazy to run one from a 1200W invertor with the engine running a 120A alternator? I can use an angle grinder like this... but have no idea how much juice the vacs consume.

[ditchcrawler]

Thanks for this... My plan has been a 33.3/67.7 mix as we're on the south of England. Would using deionized water help inhibit corrosion?

 

As we're often between places, I've ordered a Pela; seems a sensible thing to own. It also solves the broken brass sump pump issue, and should help me drain the dregs of the water tank for re coating. (That's a job I'm looking forward to)

 

As for wet/dry vacs...would it be crazy to run one from a 1200W invertor with the engine running a 120A alternator? I can use an angle grinder like this... but have no idea how much juice the vacs consume.

Lots of vacs are bigger than that, I had to look around to find a normal one under 1500w This one is on your limit http://www.toolstation.com/shop/p20075?utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&mkwid=s2qdl6yIg_dc&pcrid=46329954863&pkw=&pmt=&gclid=Cj0KEQjw-46sBRD7x6P0stibwbsBEiQA

[BargeeSpud]

Thanks for this... My plan has been a 33.3/67.7 mix as we're on the south of England. Would using deionized water help inhibit corrosion?

As we're often between places, I've ordered a Pela; seems a sensible thing to own. It also solves the broken brass sump pump issue, and should help me drain the dregs of the water tank for re coating. (That's a job I'm looking forward to)

As for wet/dry vacs...would it be crazy to run one from a 1200W invertor with the engine running a 120A alternator? I can use an angle grinder like this... but have no idea how much juice the vacs consume.

No, you'll need a lot more than that, a 2kva generator or landline. I only suggested the VAC because its quicker & easier than a hand pump or cobbling together a bilge pump.

[system 4-50]

Using deionised water is a good idea for systems that take a lot of water every day. For a closed system where the total volume of water is quite small I don't believe there is a discernible benefit. So I use tap water in my engine cooling system (but deionised in my iron!).

[Rendelf]

Lots of vacs are bigger than that, I had to look around to find a normal one under 1500w This one is on your limit http://www.toolstation.com/shop/p20075?utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&mkwid=s2qdl6yIg_dc&pcrid=46329954863&pkw=&pmt=&gclid=Cj0KEQjw-46sBRD7x6P0stibwbsBEiQA

 

Cheers.... I'll have a look-see.

 

Got my Pela now... what a great device! I changed every drop of coolant from the system, without spilling a single one!