Last weekend we drove about 10 miles to a shopping center and just as we arrived we noticed smoke/steam coming from under the hood. I opened it, noticed radiator fluid dripping everywhere, and after it cooled noticed the overflow cap was loose. I filled the radiator with water & we were on our way. My wife drove it as normal the next week, mostly short trips but one to the same center, no problems. Then exactly 1 week later, at the same center, we had the same problem, steam, radiator fluid everywhere, but this time no loose overflow cap. I filled the radiator with water again (about 50 oz to fill) and it seems to be fine again. There are no sign of leaks when the car is parked. I’d appreciate any ideas out there.
Did the engine overheat in all this excitement? If it did, you could have major damage (e.g., warped heads). Plain water is OK for an emergency fill-up, but you want to replace it with the proper coolant mix. It’s even possible that with too little antifreeze in the mix, it boiled over at too low a temperature. Finally, it’s possible that the radiator cap has gone bad and is releasing at too low a pressure, or the thermostat has gone bad and is refusing to let water circulate into the radiator (resulting in overheating). Both are fairly cheap to replace. Lots of things to look at!
Thanks Mr. Phil, It did heat up a bit, but we stopped right away, let it cool down and added water right away. Haven’t noticed anything different about the driving. I guess we’ll take it in ASAP, don’t want to risk engine damage. Do you think thermostat replacement would be simple for a rookie? I change oil myself and have done a few minor repairs. I can do them if I have good instructions/diagrams and if the part is relatively accessible. Thanks for the info.
Thermostat replacement is usually very easy-usually just 2 bolts to remove. I would guess this is what is happening: The thermostat is not opening or is getting plugged up with crud, the car overheats and creates excessive pressure which opens the radiator cap to relieve pressure by venting out some fluid. Replace the thermostat yourself to see if this solves the problem. When you get the new thermostat make sure you get a new gasket with it.
Yes, thermostat replacement is normally an easy and straightforward repair, as long as the housing for the thermostat is easily accessible. I don’t know if you would have to remove any other items in order to access the thermostat on your Honda, however.
But, whether you replace the thermostat or have a mechanic do it, it is vitally important at this point to drain the highly diluted water/antifreeze mixture that is sitting in your cooling system, and have a proper 50/50 mixture added. I would suggest flushing the cooling system first, and then adding the proper mix of antifreeze and water to it.
Of course, all of this is predicated on the engine not having sustained damage from the overheating incident(s). If there is any further sign of overheating after the procedures that I mentioned above, then you definitely need to have the engine checked for damage.