91 escort overheats

my escort has had a waterpump change when the timing belt was replaced 2 yrs ago. I just recently changed the thermostat because it is overheating. It is still overheating. I can idle for a hour without any problems. The fan cycles and the temp stays between the O and the R on the gage. NORMAL. when I drive it gets up to the A or even the L. The thermostat given to me by the auto part store was a 195 degree stat. I suspect that the core passes are collapsing when the rpms are up and the water pump is pulling harder. It happened in my bronco. Any ideas? Similar problems? Help!! Its driving me crazy. Also I have a crack somewhere in my exhaust manifold from a previous cooling issue. Is that normal? It runs smooth with no exhaust steam or water in the oil. I see no water on the ground either.

[QUOTE=Jerseydevil1965]my escort has had a waterpump change when

i have a 91 escort also and she seems to run abnormally hot, i am always in the M-L on my temp gaugue , but is your car acctally over heating or is it just getting to warm for your likings? also do you have heat when it is this hot? warm it up and crank the heat when you are driving it should drop dramaticlt , if no heat the rad is eaither too low on fluid or your themostat could be sticking half way open allowing some water but not enough in

[QUOTE=Jerseydevil1965]my escort has had a waterpump change when

i have a 91 escort also and she seems to run abnormally hot, i am always in the M-L on my temp gauge , but is your car actually over heating or is it just getting too warm for your likings? also do you have heat when it is this hot? warm it up and crank the heat when you are driving it should drop dramatically , if no heat the rad is either too low on fluid or your themostat could be sticking half way open allowing some water but not enough in

It isnt actually boiling over but it is higher than normal temperature wise. I am usually between O and R on the word normal. Now as I drive it is between M and A and sometimes it reaches L. Then as I come to a light and sit still, it does seem to drop in temperature. Especially if I shift to neutral.At that point the cooling fan is running. The fan seems to turn on and off at differet temperatures than before. I am just a little concerned due to the aluminum head warping from overheat. What would cause such a change in temp? The radiator is full and the thermostat is new. I get heat from the dash when it is warm but the air from the dash seems to cool after the cabin fan runs for a few minutes.

Try the most simple things first. It sounds like your radiator is clogged up. That and your heater box. Both can be unplugged if you get a Prestone flush and fill kit. You put a T fitting in the heater hose and hook it up to a water hose. It back flushes the whole system. It tells on the package how to do it. I think your radiator is marginal and needs to be flushed out.

I second the notion. Clogged radiator. When it overheats feel the lower section of the radiator. If it's cool to the touch then there's no flow.