well, the thermostat takes about 35 seconds and a 10mmsocket to remove and costs like $5, so start there. It could also be the water pump, but its unlikely. You also may have air trapped in the system. See if you do and try to burp the system to remove it
1. First and foremost, check the thermostat. Easy removal and replacement if necessary. You can check it by putting it in water on the stove and heating it up and using a meat thermometer to see what temp it opens up.
2. If that is fine, then get the car running and on an incline w/ the radiator cap off. Rev it up a few good times and watch the coolant in the radiator. If it's moving pretty good, then your pump is probably ok. Burp the system real good and then try running the car around a bit.
Give us some more info on the over heating though. When does it do? Certain conditions? Certain temps outside? Time of day, etc. This might help some of us give you some more insight into what might be happening.
just changed the thermostat and it fixed exactly what symptoms i had which were the same as yours. it's right off the top hose fromthe radiator. check the TSRM. i'll get a pic tomorrow if you still cant find it. it took me about 10 minutes watch for all the coolant that's gonna escape.
Yeah I agree it's prob. the thermostat. If it was the waterpump, you would most likely see some visual leakage too, and a BHG shouldn't be making it overheat as long as you're sure there is ample coolant in the system. You may have a BHG if there is air in there, but chances are your thermostat being clogged is making it overheat. My friend has driven his BHG Supra around for 15k with no overheating problems as long as he keeps it topped off on coolant. The thermostat is located where the top radiator hose hooks into the water outlet housing.