can a water pump fail without obvious signs?

Post by **Rob_Jennings** » Fri Jul 18, 2008 2:15 pm

hummm

brought the mini to work today, popped into town and the temp gauge was swinging towards hot. turned on the internal heater which did not get hot at all, just warm so i assume only convection taking place.

rad was full and hot and I got a decent puff of steam as I opened the cap.

so i guess I'm stuck with the pump having failed? it turns OK and does not drip water but can the impeller part break off? otherwise whats the chances of an airlock in the system?

Post by **PSL184** » Fri Jul 18, 2008 4:07 pm

Yes, impellers can fail, break, fall off and even rot away. I had an old Cortina years back that the impeller had all but dissolved!! If the seal hasn't failed then you won't get a leak, although it is usually the seals that go first. Older type water pumps are repairable. I've seen some where the impeller, shaft bearings and seals can be withdreawn and overhauled. Otherwise it's £20 for a new one....

Post by **Peetee** » Fri Jul 18, 2008 5:16 pm

Yes as mentioned by PSL, the impeller is an interference fit on it's shaft and can just get slack. Shaft spins - impeller doesn't

Post by **paulhumphries** » Fri Jul 18, 2008 6:09 pm

I've had the impellor on a pump (cann't remember what car) corrode so bad that the vanes had virtually dissapeared.
Other than temp rising when stationary no other symtoms so was difficult to diagnose and pump was checked as a "last restort".

Paul Humphries

Post by **bmcecosse** » Fri Jul 18, 2008 8:16 pm

Not seen an original pump with impeller rot - but newer ones seem to have pressed steel impeller which can of course rot. I suspect Mini heater valve is not properly open - or the hoses have a kink in them ! Try flushing it with garden hose. I doubt it will be pump problem.

Post by **Rob_Jennings** » Fri Jul 18, 2008 10:24 pm

problem located....

released an airlock in the system and it drank 1/2 litre of water, went for a drive and then eventually the temp rose again, another full litre of water in....

close inspection the bottom hose has bulged and has the tiny hole, so guess the new rad cap i put on 2 weeks ago has accelerated this hose falling apart.

will change the hoses top and bottom, back flush and consider a lower stat (mini is such a confined engine i would rather it ran cool) looks like i have to remove the rad to do any of this so much easier on the minor where you can get your hands in. The mini is such a knuckle scraper

Post by **bmcecosse** » Fri Jul 18, 2008 10:30 pm

Rad comes out easily on a Mini - take the grille off - then just remove the single long bolt through the bottom rad bracket, then the two nuts on the stat housing - and remove the top hose and undo the bottom hose at the water pump - and then wiggle the rad up past the fan.

Post by **Rob_Jennings** » Sat Jul 19, 2008 6:40 pm

hummm rad does NOT coem off easily on my mini it seems

70's cooper engine
2 part cowling, removed top half can get at bolt holding bracket on, so remove bolts to rad from bottom half, but its cannot clear the fan book of lies tells me to remove the fan, but i cant remove the fan without removing the rad (oh, theres a hole in my bucket dear Elise .....)

so brute force bend the lower bracket and rip the rad out (damaging it in the process but we have already gone too far in this job)

only solution i can see is take the car of the sub frame to get it back together (so like a modern car)

or

electric fan that sits behind the rad in the square to the wheel? that would mean i can clear everything back without engine driven fan in the way?

any advice?

Post by **bmcecosse** » Sat Jul 19, 2008 7:55 pm

Well - I always managed to fiddle the rad - complete with full cowling past the fan. However - I see your car is Traveller - does it still have the steel cowling on the inner wing - with the rad snuggling up to it and a rubber 'band' around the edges ? If so - hmmm. It's not so easy - and indeed the method is to take off top half of rad cowl, then remove fan (small fingers and thin 7/16 ring spanner reqd!) and then slip the rad up past the water pump. This is why on later models - the steel cowling was eliminated! On my old Minis - I (and many others) cut the steel cowl off - but we weren't interested in originality - just running the car!

Post by **Rob_Jennings** » Sat Jul 19, 2008 8:21 pm

yes got the square cowling that pretty much prevented any movement away from the fan.

i have multi blade metal fan, so there was no getting a spanner behind it even with the top cowling off!

humm wanted it for next weekend and need it for a show the weekend after, but me thinks this is going to take longer to solve

Post by **bmcecosse** » Sat Jul 19, 2008 10:54 pm

You 'should' be able to get the fan off. Unless someone has fitted a 'Clubman' spacer on the water pump thus moving the fan closer to the radiator core ? Otherwise - you will have to fit the lower cowling - then install the rad and battle with the horrible little screws on each side - then fit upper cowling etc. Hence why we hacked off the metal cowl - and indeed it was wisely eliminated by BMC on later shells.