Water pump - how reliable

[MrCoolA]

To be fare I have had many breakdowns but after 200k+ miles no issues with the water pump

He has. Many, MANY, breakdowns. Far more than usual for a 3-wheeler.

fame at last

[tonycharente]

Hello to all,
I'm halfway through doing a routine cam belt change on my 89 Excel SE. For the last several years it has had a persistent coolant loss (I need to top up every few hundred miles) that I have been unable to locate. (No coolant in oil (sample analysed), no sign of oil in coolant, no "white smoke" or drips from the exhaust, good compressions, coolant circuit holds pressure for days using pressure testing kit, and of course no visual signs of a leak anywhere, nor wet patches on the floor. ) So my thoughts were that perhaps it is leaking from the water pump, but only when hot and running, making seeing anything coming out very difficult.
With the bonnet off and all the belts and pipes removed, I have now been able get a really good look at the water pump - and I can see and feel nothing at all wrong with it. (No traces of dribbling from either little hole and no play at the pulley. )
So now I have a dilemma: to leave as is, or to change the pump. The car has done 97K miles and the pump does not appear ever to have been changed, so my first thoughts were to change it anyway, even if in fact it's still just fine. After all this is a routine procedure on cars where the water pump is driven off the cam belt. But the problem here is that it would seem (???) that I can't just buy a brand new pump anywhere, but am faced with having to have a rebuilt pump - my own or somebody else's. Which, I fear, may or may not actually last any longer than my existing pump if I simply leave it in place.
So now, at last, my questions:
What have I not thought of in trying to locate the source of my coolant leak?
What traces of leaking should I expect to find on my water pump if it is the cause of the problem?
Is there nowhere I can buy a brand new water pump?
Who does the best water pump rebuild? (I live in France, so the UK is likely to be the most convenient, but convenience is not my prime objective.)
All thoughts and suggestions very welcome,
Many thanks,
Tony.

[amarshall]

Your leak could be from a small crack in the radiator. The rad. mounting is pretty flimsy and they do flex. If there's a crack it may only open occasionally due to the flexing.

[lambert.john]

Slight coolant loss is to be expected with these cars as the radiator sits very low in relation to the engine. This can be exacerbated if you insist in topping it up to near the brim each time. In the earlier Elites/Eclats the situation was much worse as those cars had only a single header tank - the twin tank introduced in the Excel did improve matters considerably.

I would not worry too much unless the coolant loss is obvious.

[amarshall]

Slight coolant loss is to be expected with these cars as the radiator sits very low in relation to the engine. This can be exacerbated if you insist in topping it up to near the brim each time. In the earlier Elites/Eclats the situation was much worse as those cars had only a single header tank - the twin tank introduced in the Excel did improve matters considerably.

I would not worry too much unless the coolant loss is obvious.

Some Excels do have the single tank, so some coolant loss is normal on them.

[tonycharente]

Thank you both for the very rapid replies about my leak issue.

I will try and inspect the radiator better whilst I'm in "bonnet off" mode.

My Excel does have the twin-tank header tank system, and in my earlier years of ownership I don't recall having to keep topping it up. My procedure for the last few years has been to just drive it until the low coolant (AKA "Fan Fail") light comes on, at which point the coolant has dropped down to the level of the sensor towards the bottom of the front tank, and then to fill the front tank. And off I go for another few hundred miles, before I have to repeat the process. Surely this cannot be "normal"? (And as I said above, in my earlier years of ownership I don't recall having to keep topping it up.

I will definitely try to look at the radiator more closely, thank you.

Meanwhile, any thoughts on my water pump queries, please? What mileage do these later pumps normally do?

Tony

[IanM92]

This maybe a daft idea but are there dyes that can be added to the water which would leave a visible mark at the leak?
I did 1100 miles on the Croft weekend and as far as I could tell lost no coolant so I do not agree that even a small loss is to be expected.

[barker_001]

Tony, my water pump is still original after 105k and seems to work perfectly. However, I've had lots of problems with leaks from my radiator, which has been recored twice and repaired twice in 6 years. Now you have the bonnet off, I would get the nose of the car undercover somewhere, run it up to temperature / pressure, and watch for any wisps of steam rising vertically from the rad, The bottom corners seem to be the most prone. Look carefully in through the intake grille at the bottom corners to see if there is any trace of coolant running away on the undertray. Also, find the bottom mounts of the rad (an M6 nut on a thread over a large washer). If there is any dampness or a dewdrop on the thread, the leak will probably be in the corresponding bottom corner. Been there, done that, several times...

Incidentally, in between rad failures, my car doesn't appear to use any water either. The header tank "finds" a level about an inch below the filler neck (the specified fill level in the service notes) and stays there.

[chrisw2811]

When I replaced my head gasket (a leak had pressurised the coolant system) I removed the radiator and had it leak-checked because I thought coolant might be leaking from it. Gerald Turner's advice when re-installing the radiator was not to tighten up the mounting nuts fully because body movement and flexing can distort the radiator slightly. I put some rubber O rings on the threads and left a turn or so of clearance. Not had any leaks since.

[tonycharente]

Many thanks for the suggestions about possible radiator problems. I could find no visible signs of problems with the radiator, so today I reconnected the coolant pipes and filled the system so as to be able to connect up my pressure test kit again and look for any leaks from radiator with the bonnet off the car. To my surprise (given that my system seems to hold pressure despite losing coolant somewhere, and also given that I could see no trace of leaks on the water pump now I can see it properly, I had a very clear leak coming out of the little hole on the water pump - and this at 5 PSI. Pumping away like mad I could only get the pressure test kit gauge up to 10 PSI, at which pressure there was an actual flow of water coming out of the hole on the water pump - so clearly I have to replace it. On the other hand at 10 PSI I could see absolutely no leak from the radiator... Will test it again once I've replaced the water pump and before I put absolutely everything back together.

Given that I now definitely am going to replace the water pump, here are my original questions again, please:

Is there nowhere I can buy a brand new water pump?
Who does the best water pump rebuild?
I live in France, so the UK is likely to be the most convenient, but convenience is not my prime objective. However if I bought a repair kit I could get my pump repaired locally - any thoughts on that? Any experience of the kits up on eBay?

Many thanks,
Tony

[tonycharente]

Hello all,
Thought I'd provide an update of how it went. I removed the water pump as a part of the changing-the-cam-belt operation, and sent it off to SJ Sportscars to be refurnished - that way I was certain that the one I got back (my own...) would fit. Cutting a long story short, since refitting the refurbished pump several months and a thousand miles or so ago I now have no coolant leak. So it would appear that all my years of living with an untraceable leak, testing this that and the other to try to find it, were all down to a tiny leak at the water pump, presumably only when it was hot and running, and this despite there having been no coolant stains... "Go figure", as I believe our American friends might say...
Tony