I'm doing a cooling system flush and water pump RR on my 96 80. While doing the oil pump and crank seal replacements I noticed that my water pump squeaked when rotated by hand and had a very slight amount of play, so decided to RR that while everything was apart. Glad I did as once I had the old pump off it was easier to feel the play in the axle shaft.
I've read through a bunch of previous flushing threads but in my case the water pump, fan, and belts are already out so no chance to run the engine. After draining the coolant with the heater valve fully open I flushed the system using a garden hose stuck into the radiator top where the pressure cap sits with the old water pump and radiator drain plug out. I did it a few more times until all the water coming out of the radiator was clear with no smell of coolant.
Edit: I found an interesting block drain plug with a mini-drain pipe attached; it's a 14mm steel pipe plug with external threads that screws into the block with an internally threaded hole to accept a 10mm brass bolt in the center (see photos below). It looked like it had never been opened before. I cleaned it up with an acid product meant for removing rust from clothes and was surprised how strong that stuff was, only took about a minute to remove the corrosion. What all the other threads say about opening the block drain are correct. After flushing via the radiator a few times with the water pump removed and the radiator drain out and no water in the system, when I opened the block drain I still got at least two more quarts of undiluted coolant. To reach the block drain I got on my creeper and positioned myself head first facing the front of the vehicle and reached up with my right arm and unscrewed it (had loosened it earlier via the wheel well).
Next time I drain the block I'll hold the main plug with a 14mm wrench while turning the brass bolt with a 10mm wrench. Probably also will put a section of rubber hose on that little drain pipe to better direct the coolant into a pan.
I've read through a bunch of previous flushing threads but in my case the water pump, fan, and belts are already out so no chance to run the engine. After draining the coolant with the heater valve fully open I flushed the system using a garden hose stuck into the radiator top where the pressure cap sits with the old water pump and radiator drain plug out. I did it a few more times until all the water coming out of the radiator was clear with no smell of coolant.
Edit: I found an interesting block drain plug with a mini-drain pipe attached; it's a 14mm steel pipe plug with external threads that screws into the block with an internally threaded hole to accept a 10mm brass bolt in the center (see photos below). It looked like it had never been opened before. I cleaned it up with an acid product meant for removing rust from clothes and was surprised how strong that stuff was, only took about a minute to remove the corrosion. What all the other threads say about opening the block drain are correct. After flushing via the radiator a few times with the water pump removed and the radiator drain out and no water in the system, when I opened the block drain I still got at least two more quarts of undiluted coolant. To reach the block drain I got on my creeper and positioned myself head first facing the front of the vehicle and reached up with my right arm and unscrewed it (had loosened it earlier via the wheel well).
Next time I drain the block I'll hold the main plug with a 14mm wrench while turning the brass bolt with a 10mm wrench. Probably also will put a section of rubber hose on that little drain pipe to better direct the coolant into a pan.
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