does anyone know why im having so much trouble with heater cores going out on my 77 ford f250 w351m 4x4. this will make #5. ive tried new thermostat.....new cap 13# like books say

any help would be great

scott

 

Exactly how do they go out? Rupture? Corosion? How long does it take for them to fail? 5 in a lifetime is way to many for it to be bad cores. It has to be something else, so more info would help.

 

I second That !.
are you punturing them when you install them or have them installed ?.

 

They appear to go out from pressure. The last 3 heater cores have blown out in different spots. The only thing I haven't done is put on a new water pump. The last 3 haven't lasted a month. There is atleast half and inch between the A/C and the heater core. Plus, all the different spots that leak have no sign of rubbing.

 

To Have a good heater core fail from pressure is near impossible. The radiator cap would let off pressure long before that happend. Before you replace it again, Try this.... pour about 1/3 box of baking soda in the radiator and let it run for about 15 minutes so that it mixes completely with the coolant/water. This will nutrelize any acids that may be in the system from any radiator/coolant system cleaners. drain the system, refill it with water only and run for awile. Drain it again. Fill the system with a 50/50 mix of name brand anti-freeze and DISTILLED water (you can get it at wall-mart for about 70 cents a gallon, get about 3 gallons). This will eliminate any potential chemical reactions that may be caused by the minerals in your water, and the metal of the heater core.

Make sure you get a good Brass heater core not an aluminium one. Make sure your radiator cap's pressure relief valve is in good working order (I'd get a new one to be sure). And lastly. Make sure you arn't dimpling, nicking, denting or harming the core in any way during install.

This should cure your problem. I personaly suspect that you have a high acid content in your coolant. This can be caused by cleaners, a radiator rebuild, or cheap anti-freeze after a year or two in service. Good luck! I know what a pain it is to replace one.

 

Ruzzzell
I work in a window manufacturing plant and make NEW windows every day. However, we do not always produce quality windows due to several factors (new employees, hangovers, you get the point)

Almost all heater cores fail at the soldered joints. I plug one end of my new cores with a hose and a pressure guage and then hook up my compressor to the other bung. After setting the regulator to 10psi, I inflate the core until the guage reads about 17lbs. of pressure and let it sit. If the guage leaks down, I mix up about 2 teaspoons of liquid dish soap and water in a garden spray bottle and spray the whole thing down until I find the leak. If its easy to get at, I just fire up the propane torch and resolder with silver solder. Good as new and will never fail due to pressure. Follow fe4ever's advice with the corrosion and I bet you will never replace that core again.
Good luck and let us know what you find out.
Krosati