My camry has been requiring more water more and more frequently. I used to not have to add coolant at all, then I had to do it every week, then everyday, then today I had to add more coolant three times today. When my car overheats it doesn't make any bad sounds or emit huge plumes of smoke, just the temperature gauge goes up. When it overheats I pull off the road and when its cool I open the radiator and fill it with water (usually it takes the better part of a gallon) and fill the reservoir to the full line. Then when I go again my temperature gauge maintains it slightly below the midddle, until it runs out of water again. There is never a puddle on the ground or anything. We've been having a bad heat wave (hottest temperatures EVER here) so I'm sure that's part of it. So, my friend suggested it might be the thermostat, so I got one and went to have him replace it and he noticed that there was water bubbling up out of the top of the radiator. I don't mean the opening where the cap is, I mean all along the top, the whole length of it. I thought this was normal radiator behavior (hey, I never said I was in any way mechanically inclined) and he said it was cracked. So, we got some stop-leak stuff, and put that in, then he put some "jd weld" stuff on the outside to seal it until I can get a new radiator. He said it wasn't the thermostat because it maintains a steady temperature when it has water, warms up efficiently in cold weather as well. Then he suggested it might be that the heat sensor is broken because while it was running at his house the fans did not come on. When I got home I put it in park and looked under the hood with the engine still running. It was at operational temperature and no water or steam was hissing out or antything, and then while I was watching it with the hood up the fans came on. I really don't know if they did before or if they magically just started working after he sealed the radiator. So, to make a long (very long) post end, my question is, what could have caused my radiator to crack? I don't want to just treat the symptom (cracked radiator) and have this occur again in the same or a different location. Could it be a thermostat, heat sensor, mysterious blue smoke? I have no idea. My can runs great, though it does idle a bit rough which a mechanic once told me was a broken engine mount, which has been that way for years. It's a 2200 engine, four cylinder, LE edition 1993. AC works great as well. That's all the information I can think of, I didn't want to leave anything out. If you need to know more just ask! Thanks so much for reading such a long posting, you have patience!

Also I wanted to add that when my friend was putting the coolant into my radiator he would fill it up all the way, then press down on the top radiator hose, then put more in, so on and so forth. I never did that cause I didn't know you were supposed to. Could my car have been overheating because there was never actually enough water in there to begin with? Just a huge air bubble? Could that have caused my fans to not come on?

I would replace the radiator ASAP, before it costs you $2,500 to repair damaged valves and head. Radiators tend to last about 150,000 miles. Phosphate scale and leaking seams cut their life short.

Wow yeah. My car has 213000 miles. Getting a new radiator this weekend hopefully! Thanks!

I tried to rate tex, but couldn't. Yes, I also agree with what he said. Get that rad asap!
Your friend was right also. '93+213K? Reason enough for me why the rad cracked.

Pretty good though, considering it's the first thing to ever go "bad" on my car, of course with the exception of tires and brakes and oil.