2000 Ford Escort ZX2 running hot

Did you check the coolant level? A worn radiator cap (they should be replaced every two years) may also prevent coolant from flowing to/from the reservoir. You may also need to replace the thermostat. Those are three simple things to check or replace. After that you have to investigate a little further (blocked/plugged radiator, check for hydrocarbons in coolant)

I checked the thermostat when I was replacing one of the sensors and it seemed to be in decent condition. There was no visible damage or wear and was not jammed or anything. I believe I also replaced the thermostat one or two years ago (multiples cars to work on, sometimes forget which one I did what too). As for the radiator cap, do you mean on the coolant tank or the direct radiator line? I'll double check the coolant level, it seemed low when I first noticed the heat so I put in some water. Should be ok, but now that I think about it, it still might be a little low. Do you think having it slightly low would lead to this problem? The odd thing is that it doesn't heat up indefinitely, for some reason it is stopping at about 75% and I cant imagine why. Thanks for the help so far though

I would let the engine get up to temperature, then add it to the "hot" level line on the reservoir tank. The radiator cap to check/replace would be the one on the radiator (or on the coolant hose itself) not the reservoir. If it can't make a good seal, the radiator can't function properly. So top off your coolant and keep a careful watch on it. If it is losing coolant, you'll have to figure out where it's losing it. A good inspection of all the hoses may be in order too, make sure there are no cracks near the ends/hose clamps.

Thanks Ken. Also, now that I think of it, I replaced the head gasket for one of my cars and need to check my records to see which one it was. Furthermore, the cooling fan switch needed to be replaced, so the engine could have initially been heating up from that and the head gasket took issue and is now continuing to have problems. If I check for hydrocarbons, is a simple block tester reliable enough or should I try and find one of the electronic sensors? I'll double check the hoses, but I think those are in good shape. Also no drips underneath the car. But I'll double check. Hopefully it is as simple as the radiator cap.

I've always relied on the block tester, if that was positive I moved on to a compression test. If the compression test failed, I did the "wet" compression test, adding 1-2 teaspoons of oil to each cylinder, to try and determine if it were the rings versus the valves/head gasket causing the loss. (the oil will seal the rings better for the duration of the test).

Went to drain and replace the coolant last night, realized I didn't have enough to fill it back up...will do that later. I had put in some water when it first was overheating, and I'm thinking this screwed up the coolant/water ratio. This seems to make intuitive sense as to why it would only heat up to a certain temp because the boiling point changed due to the difference in the mixture. I am not positive though, I'm hoping this is the problem. Will check in tomorrow with updates.

Finished the coolant. Drove around and the engine still heats up to 75% and the service engine light is still on. I'm fairly certain the thermostat is ok because it is relatively new but it could be malfunctioning (optimistic/hope). Worth replacing a cheap part. Besides that, I'm questioning several things: the wires for the cooling sensors and the sensors themselves. The cooling fan used to not turn on, I replaced the sensor, and now it is on all the time...Whether this is a result of the sensor being bad, or the engine actually being hot, I'm not sure. As for the gasket guess, I would be surprised if it is the gasket because it is not displaying general head gasket symptoms (bubbles, smoke, milky oil, etc.) Also, I feel as though the engine would overheat if the gasket was compromised. I may not be an expert, but breaking down the situation as follows makes sense: the engine is heating up when driving to a certain point then stopping...this means the coolant is circulating at least at some point (although maybe the thermostat isn't opening up enough or is opening too late). I know the coolant is good, seeing that I just replaced it. The cap is good (no scratches, chips, wear/tear). Where to go from here is a little unclear. You've been helpful with suggestions so far, what are your thoughts on all this?

I'm having the exact same issue on my 2000 ZX2. I've replaced the thermostat and both sensors on the thermostat housing, but still running hot and fan won't come on unless I unplug the top sensor(fan switch) or turn the ac on. Did you get yours fixed?

Did anyone figure this out?