Original 3.0 OHV Vulcan engine replaced a year ago with another Vulcan because original rusted out. Heater is bypassed by hoses when used engine was put in at that time. My fan belt broke a week ago, the car nearly overheated for a moment but I pulled the car into a parking lot and replaced the fan belt. The car does not overheat.
Figured it was time to replace the coolant, I tried to drain the radiator, a little came out at a good rate but then it started dripping with only a few cups’ worth in the pail. The front of the car is on ramps to make room for a five gallon bucket. I turned the car on, let the radiator drain cock open, and opened up the radiator overflow cap. The idea was to have the coolant drain out the radiator, and add new water as the care ran at operating temp. Doing this will eventually flush out the old coolant. Only problem was, the amount coming out of the radiator was so small, the only water coming out of the car after perhaps a minute was not out the radiator drain, but out of the coolant reservoir overflowing onto the driveway. I let the car run for a long time and it was at operating temperature on the gauge so I know the thermostat was open.
Aside from preventing me from draining the coolant out the correct way and taking the bucket down to the Hazardous Household Waste site to be disposed of properly, there does not seem to be any way to get enough of the old coolant and dirty water flushed out with new water so I can add the new antifreeze.
Why does the water come out of the radiator at a decent clip for only a minute, then go drip drip drip? I’m not getting enough new water into the system to properly flush it out. Advice is appreciated.