The Stovebolt Site Forums The Shop Area Engine Shop water pump failures - how common on 235's

HI all,

Besides my recent post on my shifting problems with a new clutch a few minutes ago, I also experienced what appears to be a water pump failure on my last drive. I parked it to get gas and she lost a significant amount of coolant. I looked under the hood and traced it down to apparently coming from the bottom of the water pump ( weeping hole?)

I have a friend mechanic who told me that most pumps of this era had a way to blow out excessive pressure so things like bearing failure, etc. in the pump did not send things into the block. The question I have is that the pump appeared to be quite new and I am wondering where else I might want to look for root cause of the problem. I have not had any overheating issues, and the temp gauge does work - it starts cold and ends up in the middle ( although I understand it does not prove it is working ) - I have not had any coolant exit via the overflow tube and I checked the coolant a week before and it appeared very clean and up to the cap when cold and in my garage. Besides buying a new pump, I have also bought a new thermostat ( 160 degree ) with the little hole in the thermostat, per my friends suggestion to allow trapped air out - I am wondering now what else might have caused this. Although I am not pleased having to buy a new water pump, I will be quite relieved if this is the problem, instead of a clogged block, etc. - thoughts? - I should add it is a 55 first series 3100, 235 and I drive it locally for pleasure only about 1 hour at a time - no towing or anything above about 50MPH. Yesterday when the pump went out it was the hottest day I have driven it so far with temps in the low 80's

Since I have the courage to tackle replacing a water pump, and thermostat - does anyone have some words of wisdom to look for in case the failing pump is symptomatic of something else I should be looking for?

thanks

Joe

The leak is caused by a worn out bearing. Once the shaft starts wobbling, the seal can no longer do its job. Try to avoid over-tightening the fan belt, as this can significantly shorten the life expectancy of water pump bearing, as well as those in the generator/alternator.
Carl

Hi Carl
Thanks for the suggestion. I used to check tension by measuring deflection at mid point - I am wondering if this is still good and how much deflection I should see - stock motor with no power accessories

Thanks for your response - I hope to replace the pump tomorow

52Carl,

Do you know how tight (what torque)the fan bolts should be?

Thanks,

John

25-35 ft-lbs

Shop manual (47-51) pg 6-39 shows deflection as you measure to be 3/4" at midpoint.