I'm sure you've checked and made sure you have no coolant leaks. What kind of tank are you using, the plastic or metal one? Do you need to fill the tank every so often or does it stay full? When is the last time you've replaced the water pump? The following could be your problem, so I figure I would mention it. I have a metal tank, and after a while my cap didn't seal anymore and my car ran halfway on the gauge. I finally found that it was the cap-so I took the rubber seal off a similar cap and put it on the cap I was using so there were 2 seals [double the thickness], and it's fine now [yeah yeah I'll get the correct cap one of these days]. Try this: after driving your car go into the engine bay and [with leather gloves] squeeze the long hoses that go to the water pump-if there is little/no pressure in the hoses, or the pressure is all gone after 10-20 minutes of driving your car-you've either got a leak or bad cap. If you want to rule out the cap for sure then purchase a rubber expansion plug (readily available at advance auto or other auto stores], put it into the neck of the tank, expand it and run the car to test it. For the AC, drain and flush out the entire system; you gotta get whatever crud and debris you may have out of the system; and then replace the orifice and accumulator. A good shop that does AC will drain and flush it for you at reasonable price if you don't want to go through the trouble. The clutch on the AC compressor will run the entire time you have the AC on [at least mine does] unless one of the pressure switches cuts it off (very rare-only happens to me if I have the AC on and blower fan off). Shouldn't run the whole time the car is running with AC off-make sure you don't have a wire connected to the wrong place on the mode switch. If you've been refilling the system yourself, be sure to vacuum it out for a good long time before filling-as forgetting this step will cause problems in the system as well. John Hervey has the oil amounts to fill the compressor with on his site which you will need if you flush out the system. I'm not sure about R-12, but some R134 comes with oil mixed in with the refrigerant so it is very easy to over fill the system with oil. If you don't care what kind of refrigerant you use, convert to R-134 and get the recharge kit from Advance. It comes with a gauge and all that but you still need to determine how much oil and refrigerant goes in the system. Only thing you'll need to convert is the R134 adaptor for the low side. I have one, it's a right angle and I never used it; if you want it-it's yours all you need to give me for it is info on where to send it. You could still use this to hook up a gauge if you don't want to convert. -----Dani B. #5003 To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/