MazdaRx7Power

ok today i am driving to work and i notice the temp needle start to rise like 3/4 of the way up and i was like WTF!!! so i shut off my radio and after a couple secs of driving temp is back at normal. could this be that my alternator is struggling really hard trying to charge my car???? the fan clutch is less then a yr old and all my mods are in my sig...

SureShot

I had the same temperature creep two years ago in my 87. I knew overtemp would hurt it, so I went through everything: new stat, flush system, pull & flush rad, new fan clutch.
What finally fixed it? Would you believe the water pump housing? The aluminum casting behind the pump was eroded by the turbulence of the high revving pump. The bypass valve seat under the thermostat had about a 4mm chamfer eroded away, and there was a 6mm hole eroded through the wall between the inlet and outlet side.
All this bypassing gives symptoms like a partially blocked radiator. I fabricated a repair with Bondo Marine Epoxy Putty Stick. It held for a year, till I traded it for a 91.
You can get the fan clutch to bite better by bending the bimetal strip outward. Good luck..

MazdaRx7Power

the car cools fine its just sometimes whenever i have the radio on it just starts to move up towards the h. if i turn the radio off it just goes back to normal.

MazdaRx7Power

well its happened to be before. i'll be driving listening to the radio and the temp needle goes up to 3/4. then when i shut the radio off it goes back down. if i leave the radio on it stays there. i've done this a couple of times, so i'm wondering if the alternator is struggling and is charging alot. it has the underdrive pulley as well.

SureShot

I see what you mean. If your not having any other overtemp symptoms, if could just be a touchy instrument voltage stabilizer. You may have to get an auxiliary temp guage to be sure..

NZConvertible

Some time in its life, your car has spent a long time without a proper coolant in it. This is a lesson for everyone; your engine must always be filled with a 50/50 mix of water and quality coolant (ethylene glycol) for proper corrosion resistance. Someone cost you a bunch of money and hassle because they were ignorant and/or lazy.

MazdaRx7Power, I doubt your problems are stereo related. Even a decent amplified system (say 200W) is only drawing about 0.3hp from the engine. Check the usual suspects: stuck thermostat (replace it if you haven't before), blocked radiator (should be eveny hot across the tank), pressure cap(s), etc. Don't worry about the fan unless it overheats when stationary.