TNDave
09-06-2025, 08:09 AM
I have a 1998 150 EFI 2.5L
I am doing some preventive maintenance, checked the thermostats, one was stuck wide open. I replaced them with new Quicksilver 75692Q2. The are different, the old ones opened "out", the new ones are the "inverted" ones that open "in". Part number is listed for this engine. When I start the engine, as soon as the pressure gauge starts showing pressure the tell tail starts flowing a good volume, even though the thermostats should not be opening. I can hold my hand in the tell tail and it is just a little warm. The tell tail is branched off the thermostat ouutput hose, which also goes down to the bottom of the engine. I pinched off the hose below the tell tail connection to be sure there was not flow up from the bottom. Still a strong flow of warm water.
What am I missing? Should not be strong flow until thermostats open? The thermostats are installed correctly, temp sensor portion in the head. I do not think they could be installed upside down in any case.
Another issue, I got a poppit valve kit on amazon, installed it, and it is peeing out of the vent hole in the cover. I have disassembled it and double checked the assembly three times now, all is assembled correctly. I researched this, common issue is not tightening the screw that clamps the diaphragm enough, mine is TIGHT! I did see one post on line about the top gasket being too thick, when he re-installed the original gasket problem was solved. The kit I got does have pretty thick cork gaskets, so this is likely the issue not allowing the cover to correctly clamp against the diaphragm. I ordered another kit, this time it is a GLM. Hopefully that one works. No local dealers have a kit.
I am doing some preventive maintenance, checked the thermostats, one was stuck wide open. I replaced them with new Quicksilver 75692Q2. The are different, the old ones opened "out", the new ones are the "inverted" ones that open "in". Part number is listed for this engine. When I start the engine, as soon as the pressure gauge starts showing pressure the tell tail starts flowing a good volume, even though the thermostats should not be opening. I can hold my hand in the tell tail and it is just a little warm. The tell tail is branched off the thermostat ouutput hose, which also goes down to the bottom of the engine. I pinched off the hose below the tell tail connection to be sure there was not flow up from the bottom. Still a strong flow of warm water.
What am I missing? Should not be strong flow until thermostats open? The thermostats are installed correctly, temp sensor portion in the head. I do not think they could be installed upside down in any case.
Another issue, I got a poppit valve kit on amazon, installed it, and it is peeing out of the vent hole in the cover. I have disassembled it and double checked the assembly three times now, all is assembled correctly. I researched this, common issue is not tightening the screw that clamps the diaphragm enough, mine is TIGHT! I did see one post on line about the top gasket being too thick, when he re-installed the original gasket problem was solved. The kit I got does have pretty thick cork gaskets, so this is likely the issue not allowing the cover to correctly clamp against the diaphragm. I ordered another kit, this time it is a GLM. Hopefully that one works. No local dealers have a kit.