1990 90hp V4 Xflow, cooling problems

[generalleeuk]

Hi All and thanks for reading my post! I have a 1990 xflow 90hp V4. The motor has been stood 6 months over winter and when I started it today it overheated. I have checked flow and the tell tale output which seem bang on. The problem seems to be either in the t-stat block or in the leg, as virtually no water is comming out the outlet hole on the leg. If I take the hoses of both banks so the flow just runs straight to the floor the engine runs nice and cool ( ie bypass the t-stat , t-stat block and leg). I just find it weird that booth t-stats have failed or jammed up. If I blow down the hoses leading to the t-stat the flow seems restricted. Any pointers would be great!

 

[emdsapmgr]

Re: 1990 90hp V4 Xflow, cooling problems

The water pump supplies water up the tube to the powerhead. The water is circulated throughout the powerhead (and the telltale), then it goes through the thermostat housing before it dumps back into the midsection. If the thermostats do not open, it will stop/restrict the flow of water out of the block, causing an overheat. You can have a strong telltale and still have an overheat if the thermostats do not open. Pull the thermostat housing apart and check the stats for proper operation.