Hello all,
Figured I'd post this as encouragement to others about to or currently doing this. Started to replace the thermostat on the wife's '88 62 a few days ago. Of course it wasn't the several hour job it should have been. 2 of the 4 bolts holding the upper thermostat housing to the lower came out ok, the other 2 broke off. Pulled the upper housing off. As I guessed, the rubber gasket atop the thermostat was broken causing the engine to never warm up to operating temp. Also super crusty and gross. Got one of the two broken bolts out with heat, ice, and vice grips relatively easily. Last one broke off flush when I tried the same thing on it. Incrementally drilled it out with larger and larger bits until basically just the threads remained. I was somewhat tempted to remove the lower housing from the engine and do all this on the work bend rather than the confines of the engine bay, but was didn't because I was scared of breaking the lower housing bolts. Was also temped to use bolt extractors but in my experience those often create more problems than they solve. With a pick and pliers was able to curl the remaining portion of the bolt in on itself and pull it out with threads. To my surprise, the female threads in the housing had vanished from corrosion. Enter M8x1.25 Helicoil. Worked great. Cleaned up upper housing, installed new thermostat with new rubber gasket on top and new paper gasket. Adding a Prestone T to a heater hose tonight and adding some radiator flush and distilled water for a few days then flush it out again and fill up with correct mixture.
Side note, one of the nights when I had the housing off and the plugs to the upper housing laying unplugged, my wife (not thinking of course) started the engine to roll up the windows. I immediately screamed to shut it down since I knew the sensor plugs/wires were loose and near the fan. Came out ok I guess. Fan broke a chunk out of the water temp switch but was able to glue it back together. Next time when it's down for maintenance it's getting a big "DO NOT START" sign on the steering wheel for the wife. Hah.
Figured I'd post this as encouragement to others about to or currently doing this. Started to replace the thermostat on the wife's '88 62 a few days ago. Of course it wasn't the several hour job it should have been. 2 of the 4 bolts holding the upper thermostat housing to the lower came out ok, the other 2 broke off. Pulled the upper housing off. As I guessed, the rubber gasket atop the thermostat was broken causing the engine to never warm up to operating temp. Also super crusty and gross. Got one of the two broken bolts out with heat, ice, and vice grips relatively easily. Last one broke off flush when I tried the same thing on it. Incrementally drilled it out with larger and larger bits until basically just the threads remained. I was somewhat tempted to remove the lower housing from the engine and do all this on the work bend rather than the confines of the engine bay, but was didn't because I was scared of breaking the lower housing bolts. Was also temped to use bolt extractors but in my experience those often create more problems than they solve. With a pick and pliers was able to curl the remaining portion of the bolt in on itself and pull it out with threads. To my surprise, the female threads in the housing had vanished from corrosion. Enter M8x1.25 Helicoil. Worked great. Cleaned up upper housing, installed new thermostat with new rubber gasket on top and new paper gasket. Adding a Prestone T to a heater hose tonight and adding some radiator flush and distilled water for a few days then flush it out again and fill up with correct mixture.
Side note, one of the nights when I had the housing off and the plugs to the upper housing laying unplugged, my wife (not thinking of course) started the engine to roll up the windows. I immediately screamed to shut it down since I knew the sensor plugs/wires were loose and near the fan. Came out ok I guess. Fan broke a chunk out of the water temp switch but was able to glue it back together. Next time when it's down for maintenance it's getting a big "DO NOT START" sign on the steering wheel for the wife. Hah.
