Lots of history of overheating onmy son's95 Civic DX. Almost ayear ago I believe he musthave hit aconcrete parking lot curbwith the front under carridge, because when the car overheated shortly there after. When filling the radiator, the cap looked damaged so I replaced the cap, but overheating still occurred. Finally I noticed the composite top to the radiator was cracked at the top mount post. Put in a junkyard radiator, (couldn't shut the hood all the way until I pounded down the radiatior mounts enough to get the radiator to sit low enough so the hood wouldn't hit the top of theradiator cap, thats when I made the assumption the low front end hit a high immoveable objectchanged, you know how forthcoming sons can be when asked"did something happen I should know about?")Still was losing fluid so I figure the head gasket probably had had it with all the overheating so I changed it. According to the repair manual, did a self check for warp-age with a straight edge and looked to be within their limits, so noresurfacing wasdone, everything seemed fine after that. A few months went by, overheating was happening again.Never re-torquedheadbolts so in the back of my mind the head gasket went, but I continued with checking other cheaper remedies, cap was already new, put in new thermostat, still overheating, and of course it was winter, coolant can be expensive when you are buying it every week. Finally go ready to do another head gasket job, but decided before turning a wrench, I'll look for maybe a leak while it was up on ramps. Sure enough the water pump was leaking out the weephole.(damn I wish I changed that when I did the timing belt that broke a few months earlier!!) Once again, at least they are easy to work on. A few days later, reports of overheating startcoming in again. Damn! I told him to keep water in the car and check it often. You know how that went. Overheated real bad on him and looking into it saw that the composite top to the radiator split, changed the radiator again (this one with a metal top!), butshortly after more reports of overheating. So I changed the head gasket again and checking the gasket showed swollen areas in a couple spots where it goes over the water jacket. Thought this would finally do it. But no, still overheating, but now su****iously, you can only hear the water bubbling over, the heat gauge is showing normal operating temps(probably a very tired gauge at this point). I let it sit at idle and after a few minutes, that is when the it gets very hot(not be the gauge, just by the sounds of the bubbling over in the overflow tank). I filled the radiator to the very brim this morning, waiting out all the air bubbles etc etc, also took the thermostat out, just in case it was bad. Drove it on a 50 mile trip with a couple stops thrown in for good measure, when I came home, I let it cool for a couple minutes, and checked the level and maybe had to put a shot glass full of water. Doesn't look like I'm losing it when I'm driving it. I did let it run for about 5 or 6 minutes and the damn thing was boiling over in the overflow tank. In review, still haven't resurfaced the head, haven't gotten new head bolts, onlyputting water, not coolant. Any ideas on why it doesn't look like I use water while the car in driving, just when it is sitting at idle?

 

Fan not turning on? The car would cool when moving, since the coolant is flowing, but at idle it just can't keep up? Sounds like you could have fixed it by changing the switch and only spent like $30...... Just a guess.

 

The last (junkyard) radiator I put in came with an aftermarket fan that had attaching hardware (plastic clips) that attach right through the fins. I left it on but never checked it. Maybe I'll replace the temp gauge sensor (even when it boils over the gauge still reads normal), because at least then I can tell when it gets hot and then manually turn on the fan. What really sucks now is I have to get it through an emissions test by the 12th of this month and I dread it sitting there idling during the testand then having the boilover start up. I willjump the senor switch to the fan to see if that helps though. Thanks for the input, I'm dreading yet another head gasket job withthe expense of doing a headresurfacing, so this is something I can do for free.

 

The reason I suggested it is because it happened to me. I actually replaced the fan switch (I think...) on mine.