Water pump — advice sought

[oliverlane89]

Hello everyone!

Finally have our 1966 convertible back on the road after a year SORN'd.

Working through a few little niggles I'm having with her, including an intermittent water leak. Having taken advice, I have decided to replace the water pump & all surrounding hoses (none of them are in a great state). The parts arrived this morning and I've got all weekend to tackle it!

First weekend off I've had in a while, so I hope the sun is shining.

Quite apart from anything else, I'm looking for advice. Obviously to replace the water pump I'll be removing the radiator, so I'll be draining the coolant system (which badly needs doing, I got caught short last summer and topped it up with water and subsequently forgot about it, so want new coolant anyway) and flushing it out to get out any accumulated crud.

In terms of doing this properly — take out the drain plug in the engine and just put a hosepipe in the radiator and let it run?

When putting it back together, what's the best way to prevent an airlock in the system? Both engine and heater.

Shockingly little advice on all this out there as far as I can see!

Determined to be well prepared after my attempts to repair the leaky fuel system on our 1955 diesel grey Fergie — which amazingly seems to have worked, but probably purely by chance!

Finally any suggestions for cost effective antifreeze? I read a lot about specialist classic coolants that don't react badly with the copper / bronze in old cars but they seem insanely expensive...

Thanks, all!

[Monty-4]

I've read that the drain plugs can be difficult - being stuck, mucked up and/or disintegrating. I think the usual advice is to pump clean water through the whole system until it runs clear (with the thermostat out I image). This method will also prevent an air-lock - although the heater sits slightly lower so it shouldn't be an issue anyway.

I've replaced fan blades with the radiator still in place before so the pump itself may also be possible - but it's really damn fiddly that way!

[mogbob]

If you take the radiator out you can give it a good clean. The cooling fins are delicate so treat with respect. A soft clean paint brush and the hose pipe will get rid of all the crud / dead flies / moths, etc from the outside of the radiator. If it's really bad , you could pre treat it with a soluble degreasant or hot soapy water.
A radiator comb brush would straighten up any wayward bashes / small dents in the fins. Use thin nosed pliers , carefully , if you don't posses a comb brush.
The radiator drain tap is known , with the passage of time , not to be that robust, so leave well alone. With top and bottom hoses removed anyway , you can get a good flow of water moving. Stuffing an old rag around the hose neck will provide a bit of a seal. Reverse flush as well until you get clean fresh water through. Make sure the heater is " on " and that the valve is open for full circulation. So that's rad and engine block , both ways flush. The heater hoses are OK ? whilst you've got it all drained down !
Fill slowly when ready , heater still "on " and you shouldn't have a problem. Check after engine warmed up and cooled ( most important ) and check water level again. New gaskets at the ready and soak all the relevant nuts ( water pump , thermostat housing studs , hose pipe clips , radiator fixing bolts , etc ) with releasing fluid, at least the night before tackling.
Bob

[oliverlane89]

Fill slowly when ready , heater still "on " and you shouldn't have a problem. Check after engine warmed up and cooled ( most important ) and check water level again. New gaskets at the ready and soak all the relevant nuts ( water pump , thermostat housing studs , hose pipe clips , radiator fixing bolts , etc ) with releasing fluid, at least the night before tackling.
Bob

Thanks Bob!

Quick questions — when you say "new gaskets at the ready" I have the water pump gasket at the ready... I can't think of any other gasket I might need, what have I missed?

And when you say "soak all the relevant nuts with releasing fluid" is that another way of saying give them a good WD40 blast the night before?

I hadn't considered the thermostat before... that would prevent water flowing into the engine while I was cleaning, is that correct? What's the procedure for removing it without destroying it?

As for the drain plugs, if I'm not removing them (as I may destroy them in the process, which I agree would not be ideal) how is the clean water I'm pumping in through the hose to come out the other end?

Sorry for the daft questions. Learning as I go along...

[oliverlane89]

Some of those points in response to Monty-4 as well, apologies!

[oliver90owner]

First of all, does it run hot? (before it runs short of coolant). How much water is being lost? (The radiator will not remain full to the neck unless there is an expansion bottle attached to the radiator overflow). Are the hose in such poor condition they are really in need of replacement?

I ask these questions because you do not appear to know where the water is leaking. You may be making a lot of unnecessary work for nothing. On the other hand, new hoses are not a bad investment if they are likely to fail.

[oliverlane89]

First of all, does it run hot? (before it runs short of coolant). How much water is being lost? (The radiator will not remain full to the neck unless there is an expansion bottle attached to the radiator overflow).

Well, in terms of 'does it run hot' — to be honest I don't THINK so, but I don't have a temp probe / gauge fitted so I'd only be going against vague memories of how warm the engine bay was when I last drove it over a year ago.

How much water being lost — it isn't gushing out, for sure. To test it, I filled the rad with water the other day and left the engine running for 30 minutes on the drive while I tinkered with my tractor. After that no water loss. However after taking it for a 10 min drive around the lanes and back home the following day, upon parking it a little water was dripping.

I've only driven it a handful of times since she's been welded and re-MOT'd last week, but on one occasion when I was driving her back from Charles Ware in Bristol I stopped to grab a bite and noticed water running down the road from underneath upon returning to the car (parked on a slight hill).

I thought I'd bust the radiator and was worried I'd get home at all! There must have been half a pint out in five minutes. However left standing overnight with a drip tray once I'd got her home, not a drop.

The following day I topped her up and went to the supermarket. Returned to the Morris with my shopping to find her wet again.

Are the hose in such poor condition they are really in need of replacement?

I ask these questions because you do not appear to know where the water is leaking. You may be making a lot of unnecessary work for nothing. On the other hand, new hoses are not a bad investment if they are likely to fail.

You're right I don't know exactly where the leak is. As it isn't constant and only seems to come on when the engine is hot I'm somewhat reluctant to get my fingers in there as it is happening. I can say however the underneath of where the bottom radiator hose enters the water pump is wet, and the overflow (for instance), and the radiator itself isn't.

Hoses aren't AWFUL but don't look great. A lot of cracking. I'm replacing a bunch of hoses on my tractor anyway so I guess I might have got carried away.

In any case I've bought a new water pump and all the hoses that go with it, one might argue I might as well use them...

Your point about making work for myself I do appreciate though! I want to do the sump gasket on my tractor this weekend too, another job I've never done before, and I'd hate to find myself on Sunday evening with two half finished vintage vehicles and no time to put them back together...

[mogbob]

WD40 " will do " if that is all you have to hand. WD stands for Water dispersant. A dismantling fluid ...like Plusgas.... is a very fine formulation for " searching out " the tiniest of gaps between mechanical parts and is the engineer's weapon of choice when you don't want
to break things.
Removing the nuts on the 3 studs ( Thermostat housing ) needs a bit of care and the housing may need some persuasion with some gentle tapping with a wooden block and hammer. Circulate the tapping around the housing and blast the studs , once the nuts are removed. You can temporarily replace the nuts to tap the stud gently so the fluid / WD40 goes down the gap. Keep work away at it from all angles. Don't be tempted to bang a screwdriver or old chisel in , it will damage the mating surfaces. Remove the thermostat. Clean up the surfaces , like you will for the pump , scrape the worst off and polish off / clean up with a pot scourer.
A new Thermostat Housing gasket will be needed for re-fitment.

With the thermostat out you can flush trough from the top. Reverse flush through the bottom hose attachment hole in the engine. Do that before replacing you water pump. Replace the Thermostat.

If the rubber hoses are cracking , now is the time to replace. Clean up the stubs with some sandpaper or emery cloth.
Bob

[oliver90owner]

Removing the nuts on the 3 studs ( Thermostat housing )

I see no mention of changing the thermostat? The heater hose connections are a good place to connect a water hose for back flushing.

Mind you, intermittent overheating, with subsequent water loss, could be down to a sticking thermostat. But the symptoms here do not suggest that.

I would guess that the water pump gland may be leaking when under pressure while the engine is stopped. Water would be leaking from the weep hole on the pump. Other possibilities are a leaking hose or corrosion on the connector, forcing open the jubilee clip. Wire clamps are notorious for cutting into hoses, too. There is also the possibility of the head gasket leaking past a fire ring, although that would likely be regular rather than intermittent.

Leaks can easily be identified by adding a dye to the coolant and looking for it when dry. Flourescene (sp?) is easily identified with a UV lamp even if the leak is only slight.

[Smithy1961]

to establish if the water jacket is pressurising drive it with the rad cap loosened. if the leak stops you have a problem maybe as pointed out a stuck t/stat or worse a head gasket breach to the water jacket, most other leaks should be self apparent by just looking .

A clogged rad / stuck t/stat or bad pump would manifest its self as general overheating . I check the last ones by holding both top and bottom rad hoses when hot ,there should not be a big differance between how hot they are if you have good flow

[liammonty]

. I check the last ones by holding both top and bottom rad hoses when hot ,there should not be a big differance between how hot they are if you have good flow

I'd disagree with the point about the temp differential between the top and bottom hose - I've seen several posts over the years from people wondering if something is wrong as the bottom hose is often virtually cold when the top hose is hot and the thermostat open. It's quite normal, as the Minor has a relatively large radiator and the coolant is well cooled itself by the time it exits the bottom of the radiator.

[kennatt]

before you start to strip the pump off etc,just try tightening the clip on the suspected hose,the rad is designed to hold slight pressure when hot,thats why it only leaks when running,if you only have the spring type clips, sometimes they just need easing and the hoses twisting back and forwards to re seal. But if the hoses are old a good idea to replace as a matter of course. Don't worry,yet, about stuck thermostats or head gaskets,you would know if it was because you would be loosing all of the water on a run out. good luck