Ok, here's my deal, I've had bad experiences with cars lately, and have
become paranoid. In that vein, I'd say this - look up the resistance that
you're supposed to have on the sending unit. Boil some water in an open
pot on the stove. Put the sender in - check the resistance. This way you
know if it is the sender. If so, replace, if not, put it back. Check the
wiring to the thermostatic control on the fans. It really sounds like
your fan switch isn't getting a signal.
Anyhow, as far as the water pump is concerned, it is not likely to be the
problem. If you still have coolant, then it should be good. If it is
causing a serious issue, it will leak by the seal into the weep hole, and
you'd see it. There were some with plastic impellers for a while, but
most of those are gone already, all the replacements now have metal, and
don't go bad (other than cracking the housing at the alt/gen connection or
loosing a seal and leaking out the weep hole).
Phil Bates
'58 MGA with a leaking water pump
'67 MGB that cracked the housing at the alternator mount
>>Hi Listers,
>>
>>The other day my car started getting hotter after driving a couple of
>> hours.
>>Have had no problems before this. It actually got right up to almost
>> touching
>>the red line area but I got it home in time. A few days later I checked
>> the
>>thermostat in hot water on the stove and it seemed fine but I replaced it
>>anyway. I did notice that the electric fans were not kicking on like they
>>usually do when I ran it in the driveway to see if it was still heating
>> up. So
>>I jumped the wires leading to the fan switch so they would run and it
>> still
>>went right up to the red area in about 10 minutes time. I'm guessing the
>> only
>>other thing is the water pump. I completely flushed the entire system 6
>> months
>>ago. How does one go about checking if a water pump is bad?
>>
> Possibilities to check:
>
> Timing changed? Either too advanced or too retarded can cause overheating.
> Losing coolant? A small loss of coolant can cause overheating. Main
> causes are leaks in hoses or loose hose clamps, cracks in block or head or
> leak at head gasket. Not likely to be water pump.
>
> I suspect you have developed a clog somewhere in the system. Might try a
> good rad flush from Prestone or another good antifreeze manufacturer. The
> backs of BMC blocks tend to get clogged by deposits. I remove the plug or
> valve there and fish around with a piece of wire to help remove these
> clogs, then use the rad flush. Make sure the radiator is clean on the
> outside and the small open spaces in the rad are free from dirt and leaves
> and bugs and such; air must flow freely through the rad for full cooling.
>
> -Rock http://www.rocky-frisco.com
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