My A4 is from 1975, and was rebuilt by MMI in 1993. I've mentioned my water pump impeller issues before in these forums, and my inability to find a replacement of the same height to give the same amount of "crush" by the back plate. I plan on replacing the water pump over this off-season, but until then I'm running on an at-least four year old impeller.
This season I've noticed the engine is running hotter. Whether it's just the weather in the Baltimore area (much hotter than last summer), or the impeller is finally giving up the ghost or I've got some water flow blockage in the engine I can't say, but even with my bypass valve closed all the way I am still rather warm.
Yesterday as I was motoring out of the creek at my usual cruising rpms of 1900 or so, I saw the temp gauge really starting to climb -- up over 190, pushing for the 100 C mark on the gauge. I knew this wouldn't do, so I throttled back to 1500 and the temps dropped back under 180 and stayed there until I hoisted sail. The odd part is what happened on the way back in.
There were thunderstorms approaching the area, so I dropped sail further out than usual and made a beeline for the marina. I pushed her back up to 1900, keeping an eye on the gauge, but it never went over 180 this time. I had noticed this behavior another time and wondered at it then. What would make the engine run cooler on the restart than on the initial start? It didn't appear that there was more water coming out of the exhaust either time.
This season I've noticed the engine is running hotter. Whether it's just the weather in the Baltimore area (much hotter than last summer), or the impeller is finally giving up the ghost or I've got some water flow blockage in the engine I can't say, but even with my bypass valve closed all the way I am still rather warm.
Yesterday as I was motoring out of the creek at my usual cruising rpms of 1900 or so, I saw the temp gauge really starting to climb -- up over 190, pushing for the 100 C mark on the gauge. I knew this wouldn't do, so I throttled back to 1500 and the temps dropped back under 180 and stayed there until I hoisted sail. The odd part is what happened on the way back in.
There were thunderstorms approaching the area, so I dropped sail further out than usual and made a beeline for the marina. I pushed her back up to 1900, keeping an eye on the gauge, but it never went over 180 this time. I had noticed this behavior another time and wondered at it then. What would make the engine run cooler on the restart than on the initial start? It didn't appear that there was more water coming out of the exhaust either time.
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