Vintage Cars: water pump, wire coat hanger, combustion gasses

Question
QUESTION: Hi Don
Working on my 64 Pontiac 230 6 cyl.(Chev. engine).
It overheats badly.
There is good air flow through the rad I flushed it out and replaced the hoses and coolant.
When the rad cap is off,I dont see the coolant moving,it just sits there,with the odd bubble.
Does this sound like the water pump is shot?
Where exactly,can I find that puppy so I can change it?


ANSWER: It could be the water pump.  Are you saying you don't know where it is?  Just follow the lower radiator hose right to it!  It also has a pully run by the accessory drive V-belt with the fan attached.

There will be several bolts holding it on.  remove the V-belt, remove the lower radiator hose, unbolt the fan and then unbolt the pump.  There may be more involved, been a long time since I took one of these off, but I don't think the pump is part of the oil pan like the Pontiac V8's.

When you get it off, inspect it to see if the blades inside the pump are rotted off.  This can happen.

Also, you may want to remove the freeze plugs while things are apart and see if there is rust and gunk built up inside the water jacket.  This can restrict water flow and lead to uneven cooling.  Also the gunk there will harm the water pump as it breaks loose.  So clean that out well with brushes, a wire coat hanger and flush it well before you put the new water pump on.

Another cause of overheating is a bad head gasket that lets combustion gasses into the coolant.  you mention an odd bubble, and this should not be if the head gasket is not leaking.     

Also check the thermostat.  If it even has one.  It was common for people to remove the thermostat back in the 60's during hot weather, but in reality, if the system is working, that can make things worse.  If the water circulates too quick, it won't have time to pick up heat from the engine or release it into the air at the radiator.

If it does have a thermostat, put it in a pot of water and bring it to a boil.  Use a cooking thermometer to see when or if the thermostat opens.

I hope some of this helps.

Don

---------- FOLLOW-UP ----------

QUESTION: Don
I still cant find it.
The lower rad hose goes from the rad hose turns up and goes into a port just behind the fan.There are two ports actually with the top one being a smaller hose that goes to the heater.
Also no pully anywhere.Just one small belt that goes around the fan,the whell? just below it,and around the alternator.


Answer
There is only one thing that will have the fan attached to it, and that is the water pump.  The bottom radiator hose goes into the water pump.  That smaller hose is one of the heater hoses.

The "pully" is the one that the belt goes around behind the fan blades as I described.  Fan, pully, water pump in that order, all bolted together by four small bolts through the fan, pully and pump flange.

It is exactly as I wrote earlier.  Not to be indelicate, but if you are having that hard a time finding the water pump, then you really should not be trying to get it apart.

I suggest you purchase a service manual.  Chiltons should be good enough, just google Chilton's and look for a manual that covers your year/make vehicle.  

Don

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