For the last couple of days, I've noticed my engine running a bit warm. It was approaching half way, which really worried me. It would't surprise me if it was hot like that and I was driving it in 102 degree weather (I live in Oklahoma), but this was when it was relativly cool outside,

I was driving it last night when the temp went above half way. It worried me a lot, and I was about to pull over when my car made some very intresting noises. I checked it out, but it didn't seem like the cap blew, but that is what it sounded like.

I left it where I stopped for the night, to worried to drive it any more.

Why is my car overheating? Is it my water pump, as it does seem like that would be the case. It never got extremely hot (according to the gage, just above half way), but I am worried whether or not I might have damaged the engine. It is my DD right now, and I can't afford to fix a blown engine.
BTW, I made a thread because it is easier for me to understand answers when the senerio is the same as mine, and searching didn't bring up anthing identicle

 

There could be many reasons why the car is running hot. Diagnosis will depend on what kind of driving you were doing when the problem occurred.

Take a look at http://www.aaroncake.net/rx-7/cooling.htm for cooling system troubleshooting.

 

I replaced the thermestat, flushed fluid. Still hot. Do you think it is the Water pump? I don't think it is my radiator.

 

Ok. lets assume that your thermostat and radiator cap are working properly. You still are overheating, at least according to the gauge. The only way to really know the water temp is to insert a High Temp Thermometer directly into the water in the radiator.
So, lets say you are running hot but not extremely hot and it has leveled off at a hotter than normal temperature. The other two items that could cause this kind of overheating without boilover would be your RADIATOR or perhaps your fan clutch. I once had a bad can clutch and replacing it solved my problem.

I am puzzled by your "noise" mainly because I don't have enough information but perhaps the fan clutch is creating this noise. If it were me I would:
1. Get the correct temperature via a high temp thermometer
2. Replace my radiator cap (an incorrect pressure cap can cause overheating)
3. Check Water Pump Belt tension
4. Check and clean if necessary Your AC coil there in front of the radiator and the radiator grill itself as dust, bugs etc, can accumulate to restrict air flow causing overheating.
5. If all this checks out you will need to take out the radiator and carry it to a radiator shop and have it tested.

Good Luck

 

I think the noise was steam trying to exit from the pressure release next to the thermestat. The fan works fine, I'll check fan clutch. Tension of water belt is good, and I cleaned the radiator.

 

read that link that Aaron Cake posted above...there is some good info there that I, with 23+ years with RX's was not aware of.