Having spent 35 years plus dealing with pumps and fluid systems (non automotive) this is a classic symptom of pump cavitation. If a pump impeller is damaged, out of spec., improperly spaced it can cause a low pressure or vaccume condition in the pump volute that will cause the pumped fluid to flash to steam. The result is an endless "air in the system" condition. More than once I have seen a owner suffer from day one for years with air in the system. After checking all other required parameters (system pressure, piping, etc.) and finding them to be in specification it is almost always a improperly specified or damaged/worn pump impeller. If it is pump cavitation it will always get worse as the cavitation process is extremely eroseive to the impeller. YMMVAlso, some extra info is it constantly has air in it, constantly
Great info, and yes, thats exactly like its acting. I dont see how the metal impellar can be damaged though. It looked good when I took it off. I mean I didnt bump the key to see if it had a wobble in it when it spins or anything though.Having spent 35 years plus dealing with pumps and fluid systems (non automotive) this is a classic symptom of pump cavitation. If a pump impeller is damaged, out of spec., improperly spaced it can cause a low pressure or vaccume condition in the pump volute that will cause the pumped fluid to flash to steam. The result is an endless "air in the system" condition. More than once I have seen a owner suffer from day one for years with air in the system. After checking all other required parameters (system pressure, piping, etc.) and finding them to be in specification it is almost always a improperly specified or damaged/worn pump impeller. If it is pump cavitation it will always get worse as the cavitation process is extremely eroseive to the impeller. YMMV
Yes Ive done this several times. With thermostats, without thermostats, etc, etc, Thanks for the info though. 🍻My machine probably took 15-20 min with the front elevated with the cap off to bleed. After about 10 min it started blowing coolant 6' foot in the air and I kept topping it off till it quit. Every time it would spit, it would suck the coolant down, cool the motor and thermostat would close. Had to let it heat back up and repeat the process quite a few times. Also the overflow hose needs to be good and the tank with coolant. When the machine cools off, it can pull a vacuum and draw coolant back into the radiator. If it's not, it can draw air back in.
A few times in the past, I've examined what appeared to be perfect impellers (some of the ones I've to deal with are hi-4figures) and just replaced them out a of nothing else to try position. Problem gone. It sucks to have to deal with this stuff. I've had clients with complex systems almost in tears from the frustration. I'm not familiar with the Pioneer pumping layout, but, another cause could be some type of obstruction or imperfection on the intake side of the pump causing a low pressure suction issue, or turbulence and resulting cavitation. I'd say Honda is way above a bad impellers QC wise, but have known more than a few manufacturing engineers and heard too many oh $hit, how did those parts manage to get into the build stock stories. One that worked for a very reputable diesel engine manufacturing co. It happens. Good luck!Great info, and yes, thats exactly like its acting. I dont see how the metal impellar can be damaged though. It looked good when I took it off. I mean I didnt bump the key to see if it had a wobble in it when it spins or anything though.
Thank you for the infoA few times in the past, I've examined what appeared to be perfect impellers (some of the ones I've to deal with are hi-4figures) and just replaced them out a of nothing else to try position. Problem gone. It sucks to have to deal with this stuff. I've had clients with complex systems almost in tears from the frustration. I'm not familiar with the Pioneer pumping layout, but, another cause could be some type of obstruction or imperfection on the intake side of the pump causing a low pressure suction issue, or turbulence and resulting cavitation. I'd say Honda is way above a bad impellers QC wise, but have known more than a few manufacturing engineers and heard too many oh $hit, how did those parts manage to get into the build stock stories. One that worked for a very reputable diesel engine manufacturing co. It happens. Good luck!