Sticky thermostat

[Bennett French]

My Ford 2000 cooling is behaving strangely. As the engine is initially warming up the temp gage comes right up to the red line before cooling down some, but not to the range that I am accustomed to. It will then heat back up to the red line before cooling down again. This will continue for a number of cycles, sometimes cooling down more, sometimes cooling down less. Eventually it will cool down to the normal range. The only thing I can think of that would cause this behavior is a thermostat that initially is not opening completely, but over time loosens up or in some other way starts performing properly. Is anyone familiar with this kind of cooling issue? Thanks.

 

[Bern]

I've seen that when stop leak is used in the cooling system. Regardless, it's time to replace the thermostat. It's obviously sticky.

 

[Bennett French]

Thank you.

 

[sotxbill]

gas tractors will do this especially if there is no bleed port or hole in the edge of the thermostat. As the thermostat is located at the end of the intake manifold, the little bleed hole is needed to let the hot water get to the thermostat correctly. It will stop the ping pong effect. You can either buy a thermostat with the bleed hole or drill one,,, to fix this problem.

 

[Bennett French]

Thank you.

 

[Tim PloughNman Daley]

Was it operating fine til recently or had you had it out and replaced? I don't know about a 2000 but I know on the N-Series if you can get the Thermostat installed backwards it will act hinky like that. P/N D8NN-8575-AA, 168 DEG, 53-64. How's your RAD? Dirty? How's your water pump & FAN? Might be time to perform some PM on your cooling system with a good flush, or cleaning at a shop, new coolant, new T-Stat, new hoses, new clamps, new fan belt, and a water pump inspection. Just suggestions. Explore all possibilities and don't just assume culprit is only one suspect.

THE N-NEWS; KEEPING IT COOL by BRUCE HAYNES

Tim Daley(MI)

 

[Bern]

Interesting assembly line photo. Those workers don't look a day over 18.

 

[MarkB_MI]

Is it losing coolant? If so, you might have a bad head gasket. Air in the system can cause that behavior.

 

[showcrop]

Plugged bleed hole.