QuestionI have a 1999 Elantra. About a year ago I replace the radiator, water pump, thermostat, and thermostat housing. about a month ago my car overheated to the point it shut off. pulling over i saw fluid coming from the drain-cock of the radiator. some how it was loose and drained the water while I was driving home. I filled it with water and drove home. well over the last 2 weeks when the car is in motion it overheats. I have to put coolant in it every trip to and from work. as I've said before I replaced the radiator, water pump, thermostat, and thermostat housing and just to be safe i put in new plugs and wires. so the only 2 choices i have left are 1. that the catalytic converter is becoming clogged and holding heat right on the rad. (kind of a long shot i know). or 2. blown head gasket from the day it shut off from overheating. i hope my head isn't warped from that day. Hope you can help. tell me if I'm going in the right direction. thanks.
AnswerI'm willing to say the issue isn't the converter, but it is possible that you've overheated the engine badly enough that you've damaged it. If it's determined you have a head gasket issue causing the overheating, you should expect that the cylinder head will need to be replaced as well. I've never seen a head gasket problem (on a Hyundai) caused by overheating that didn't warp the head beyond repair specifications.
Before we jump to the head gasket conclusion, however, it's important to recheck some of the things you replaced a year ago. Overheating can damage certain cooling system components.
Check to be sure the thermostat is functioning correctly. I've seen thermostats damaged by overheating.
Check to be sure the coolant can flow through the radiator. I've seen radiators whose plastic tanks have been melted by overheating. As the melted plastic cools, it semi-solidifies and clogs the radiator tubes.
While not potentially damaged by overheating, it's also a good idea to check the fan operation. If you start the engine and turn on the A/C, both fans should run.
