97 f 350 blows heater cores

[dano4]

i have tried everything that i can think of in the last year (11 heater cores) i have hooked ground wires from the heater core to the fender and on to the block, cleaned all the oem grounds that i can find, flushed the system treated the water electrolisis and for the ph balance, what could be causing this, they ususally last between 600 and 1500 miles

[ryandamo]

are you using a cheap brand? did you install it correctly or is it rubbing on something, 11 seems a little high, what exactly are they doing when they blow

[dano4]

i have tried napa, schucks orielly, tisco(local international dealer) and ford i have got it down to 11 minutes i can do it in the parking lot all of the mounting rubbers are good they are getting pinholes in the top tank or in the tubes at the top where the water is hitting and dispersing when it comes in

[madpogue]

Some contaminant in the coolant? Have you flushed the coolant anytime in the meanwhile?

[ryandamo]

thats very odd, maybee try installing a coolant filter? what type of coolant are you running

[late_99_PSD]

sounds like your having pressure building in your system. Maby your cap is bad or a clogged vent?

[dano4]

we have flushed it twice, i heard somewhere that sometimes this engine has this problem and there is a flow reducer available that you can put in the pressure line leading to the heater core, it seems to do it if i am pulling hard up hill at higher rpms or if i have came down a long hill out in the woods and maybe go 15 minutes without accelerating and the engine temp is down so the thermostat is closed and then go to go uphill and it gets the sudden change in pressure or flow. i have also changed thermostat and cap

[dano4]

hmm a coolant filter i hadnt thought of that, maybe deposites in the system eroding holes in the heater core. when i fixed the oil cooler last week the block heater had mineral deposites on it and it looked like a solid bar, so i took a wire brush and a little pick and made it look like copper again. as far as the coolant i am using i have been getting it from a freind that has a fleet of logging trucks comes in a 55 gallon drum pre mixed with disstilled water

[madpogue]

Does this supply of coolant have the anti-cavitation additive (SCA), or are you adding it yourself, and measuring the concentration?

[retmotor]

Short of making this a X-File episode; if the coolant has been a constant (granted, there are other constants), try a different coolant. I don't get how the coolant would cause that, but...