That sounds like a stuck thermostat. When it unstuck and came open, then it stuck open and overcooled. Definitely replace it just to rule that out. It's not an expensive part.

The heater will not work if the engine is not completely full of coolant. Which will of course also cause overheating. Heater not working is a bad sign, means you need to park immediately to save your engine.

 

happened to me too. try running the engine at idle (in your garage or somewhere convenient that in case it overheats, you are not in a difficult place to get help), try looking for unusual water marks (squirts) under the hood and on the floor. there should be none on the hood and the floor should have the one right under the a/c breather hose only or under your freon return line (sometimes if its really hot outside). when these happen, it would be easier to pinpoint the cause of the leak. also check your radiator fan if it is running and the thermostat plug might be loose therefore giving you intermittent overheats.

 

Did a fluid flush, new thermostat and coolant temp sensor...so far so good, but still anxious at red lights!

 

UPDATE:

Car overheated today. It had been fine since the new radiator and as soon as I got to work (30 min drive) the temperature shot up after I parked the car and left it running for 1-2 minutes. I popped the hood and the fans were on as they should have been. I revved the engine and the temperature fell rapidly. I shut the car down and I noticed that the overflow reservoir had shot out some coolant and there was a visible puddle on the ground under the nose of my car and running from the car on the ground.

I took it to my mechanic, he has no clue. He can only think that it might be a head gasket...which is about $800. I'm not comfortable spending that much money on a hunch. The water pump was replaced at 88,000 miles (car has 100,000 as of yesterday), so I don't think that is the culprit. The car isn't blowing white smoke, misfiring or running rough so I don't think it is the head gasket (unless it is the beginning of the head gasket problem).

Any ideas? I'm about to just sell the freakin thing...


Just to recap, this is what I have changed:

Fluid
Coolant temperature sensor
thermostat
radiator and cap
water pump (12,000 miles ago)

 

a head gasket job is less than $100 if you do it yourself.

 

Yeah, it sure sounds like a blown head gasket. Consider compression testing the cylinders and doing a leak down test.

 

Is there a DIY on it? My neighbor is a mechanic, maybe I can give him $200-300 to do it for me. I'm not THAT mechanically inclined...

 

If you have the pressure gauge, it does not seem too difficult. Here is the forum DIY compression test:

https://www.hondacivicforum.com/m_386770/tm.htm

 

Sorry, due to the evil HCF forum virus, I cannot post the text for the leak down test.

 

linky no worky