[TR] TR3A Overheating

[Michael Porter]

On 7/14/2011 8:45 PM, wbeech at flash.net wrote:
> <moral of the story - before it finally dies, a water pump may only be
> working somewhat . . .>
>
>
> Question: How does a water pump partially wear our?  Do the vanes wear down?
> I should think that if it is not leaking and the belt is not slipping that
> it is working as intended.  Give you radiator a good check/cleaning if you
> have not already.
>
>

Corrosion can cause the pump vanes to wear down over time, and once the 
pump begins to cavitate, that can accelerate the wear.  That said, the 
pump doesn't have to leak to create symptoms of overheating.  I had one 
that didn't leak (at least not enough to notice), but the seal had worn 
just enough to suck air in due to rotation of the shaft, which would 
overpressurize the system and cause the cap to vent as if it were 
boiling over.

But, a goodly number of the Cummins diesels we'd purchased for 
customers' buses at one time were going through water pumps at a 
ferocious rate (with the primary symptom being overheating), and the 
problem was traced back to a corrosion inhibitor that was incompatible 
with the water pump vane alloy, and was accelerating the erosion of that 
part.  Once the anti-corrosion chemistry was sorted out, everything was 
back to normal.  So, it can happen.


Cheers.

-- 


Michael Porter
Roswell, NM


Never let anyone drive you crazy when you know it's within walking distance....