'97 HD cooling problem
11-14-2016, 08:19 PM
#1
'97 HD cooling problem
Howdy
I've got a '97 250 Heavy Duty with a 460.
At some point in this poor truck's life I believe someone mixed incompatible coolant types, and the whole cooling system is rusty as crap. I've done a few flushes but in the year + I've owned the thing, I've never been able to get it clean. I've also just been running water in it, for fear of adding green and just making the problem worse.
Have never had heat problems with it, though, until about a month ago - started running hot. We noticed the bottom of the radiator was cold, so figured it was full of goopy coolant/rust/sediment.. I replace it, along with the thermostat, flushed again, and ...... NO CHANGE. Still runs super hot, and is getting hotter. Actually over heats, now.. can't even drive it really.
Fan clutch seems a little weak, but not so bad that the fan isn't working... And it's still hot even doing 50 down the highway on a cool day - so I'm fairly convinced it's not the fan. What's left?
I'm gonna try running it without the thermostat tomorrow.. and assuming it doesn't overheat again, I'll try to get a cooler temp rated thermostat. Just don't know what else to do.
I've got a '97 250 Heavy Duty with a 460.
At some point in this poor truck's life I believe someone mixed incompatible coolant types, and the whole cooling system is rusty as crap. I've done a few flushes but in the year + I've owned the thing, I've never been able to get it clean. I've also just been running water in it, for fear of adding green and just making the problem worse.
Have never had heat problems with it, though, until about a month ago - started running hot. We noticed the bottom of the radiator was cold, so figured it was full of goopy coolant/rust/sediment.. I replace it, along with the thermostat, flushed again, and ...... NO CHANGE. Still runs super hot, and is getting hotter. Actually over heats, now.. can't even drive it really.
Fan clutch seems a little weak, but not so bad that the fan isn't working... And it's still hot even doing 50 down the highway on a cool day - so I'm fairly convinced it's not the fan. What's left?
I'm gonna try running it without the thermostat tomorrow.. and assuming it doesn't overheat again, I'll try to get a cooler temp rated thermostat. Just don't know what else to do.
11-15-2016, 08:29 AM
#2
I've been fighting this same rusty problem in my 351. I replaced the entire cooling system from the radiator to the heater block and still get rust. Still no luck. I don't have the overheating problem though.
First, make sure the water pump is working. It doesn't sound like it is. After filling the system with fluid, and with the radiator cap off, you should see the fluid level in the radiator rise and fall when you hit the throttle, bubbles too. If nothing happens I bet the pump is dead.
If I were you I wouldn't run straight water though, it needs the correct coolant to keep the temps down. Test the thermostat also by putting it in a pot of water, bring to a boil, and see if it pops. Have you replaced the radiator cap? They are pressure sensitive and critical to coolant temps just like the thermostat. Pressure is key to keeping the coolant system operating as it should. It may also be a good idea to pressure test the entire system.
First, make sure the water pump is working. It doesn't sound like it is. After filling the system with fluid, and with the radiator cap off, you should see the fluid level in the radiator rise and fall when you hit the throttle, bubbles too. If nothing happens I bet the pump is dead.
If I were you I wouldn't run straight water though, it needs the correct coolant to keep the temps down. Test the thermostat also by putting it in a pot of water, bring to a boil, and see if it pops. Have you replaced the radiator cap? They are pressure sensitive and critical to coolant temps just like the thermostat. Pressure is key to keeping the coolant system operating as it should. It may also be a good idea to pressure test the entire system.