Hyundai Elantra Antifreeze Leak
if the fan NEVER comes on anymore, then that's why your engine is getting hot. You need to figure out if the fan switch relay is bad, or if the motor on the fan is bad, or something in the electrical system with the fan is not working. if the temp. sensor wasn't working, then your guage wouldn't work. I would never have used any type of stop leak in an engine cause it can clog up your return ports from your engine's cooling system and then you have real problems later with your engine. There is so much to have to check with this vehicle to see what's the problem. However, you can check to see if the fan motor works, by unplugging the fan electrical plug, and using a direct wire from your battery to give it electricity to it directly, if it comes on, then the motor isn't the problem, it's something else like a relay or something. you can also use a test light to check the plug for the fan coming from the engine to see if it's getting any electricity to it with the key turn on, just plug in the test light to each wire in the harness coming from the engine, and making sure you have a good ground connection your tester by clipping the tester to the neg battery cable, then touch each wire to see if either of them light up the tester. if they don't, then you are NOT getting fire(electricity) to the fan through the wiring which could indicate a fan relay gone bad, broken wire someplace or burned wire someplace. Takes alot to track down electrical stuff, takes time, alot of knowledge and patience. i would take your car to the dealer, unless you know a really good shop that does this kinda work. You need to be informed of this though....YOUR HEAD ON YOUR ENGINE IS MADE OF ALUMINUM AND IT DOESN'T TAKE MUCH OVERHEAT TO WARP IT AND CAUSE MORE DAMAGE THAN YOU CAN AFFORD TO PAY OUT ON . SO DON'T KEEP DRIVING THE CAR UNTIL IT HAPPENS. GET IT TO A SHOP AND MAKE SURE THEY TEST THE HEAD FOR LEAKING WATER AND LET THEM KNOW IT'S RUN IN THE RED BEFORE.... THAT'S A NO NO FOR ALUMINUM HEADS... WILL WARP THEM IN A HEARTBEAT. GOOD LUCK.