have 2 problems, im thinking they both have to do with the stat...heat blows cold and i overheat when its really hot out...water pump, radiator, and electric fan are all working...stat is about 2 years old... oh, and one question what temp is the factory stat 195*?
today it was about 40* out and the car hit a 200..it only does it when i sit at idle like if im in town at traffic lights... if im moving it doesnt get nearly as hot... i have an electric fan and the radiator definately isnt plugged...i just bought a 180 degree stat because i was thinking if it has a 195 in it now and the car is usually running below 180 when im not in town then the stat will never open to allow the heat to work..im going to try to shut the fan off and warm it up over 180 after i install the new stat, then if the heat still dosent work its probably the core...
i dont see how a heater core could affect the overheating issue? if you can bypass a heater core and a car will still operate fine then what disadvantage is a clogged one??
I wouldn't bother replacing your thermostat. 200 degrees is not even hot. Since your car only gets hotter at an idle, that also means there is nothing wrong with your thermostat.
I forget you folks are so cold (it was in the mid 80's here today. ).
Something might be up with your fan too. While idling in town while it's so cold outside, the fan should keep your temps nearly as low as they are on the highway.
So if you have heat while the car is idling, it is possible the stat is closing and you dont have heat. It happens to older 4 bangers in the cold a lot.
I might get off a highway after a little jaunt [where you did not have heat] and pop the hood. See if the upper rad hose is very warm or hard (insert joke here). Also see if the heater hoses are warm. Be careful of hot hoses and all that.
Otherwise, I think you might be right about the stat closing for a bit of time and for some reason you get no heat.
I suppose you could try flushing the heater core. That's always an iffy proposition.
i dont see how a heater core could affect the overheating issue? if you can bypass a heater core and a car will still operate fine then what disadvantage is a clogged one??
What does the gauge say when you start the car cold?
It should Slowly rise past the normal range
into the hot range.
And then sharply fall back down to the normal
range.
That is the point where the T stat opens up.
If you see a slow rise and no fall the T stat may be
stuck open.
If you see the slow rise into hot range and not fall
the T stat may be stuck closed.
My new T stat failed after 1 year.
Sometimes you buy crap, even if it is expensive.