Hey all, looks like I got another strange problem...

My Civic runs fine when moving, but if I stop and sit for more than 6 minutes, the coolant temp starts to rise! I see the radiator fan turn on, but that doesn't help. I have to actually move forward, or turn the heater on, to get the coolant temp back to normal. I'm not talking about like 1/2 degree of rise either. The needle goes from the part it usually parks and moves a good 15+ degrees of angle UP! My coolant level is nominal, and does not leak. What could it be?

 

if fan works properly, you might have a partially stuck t-stat.. also chk the radiat cap. and last thing, the fan does spin at normal speed correct ??( not slower ) i have seen a few times that the fan will spin but at a much lower speed than normal thus causes engine to overheat

 

I checked the resistance on the fan, and it's 1.9Ω. I also took a peek in the radiator itself, and it seems to have gone down some. Funny it won't draw from the near full overfill tank! So I put some coolant back, and got the engine back to normal, for now. If I rev the engine, some water comes out the exhaust. I am hoping it's just condensation, giving the environment I live in has 150% humidity, and the fact that coolant isn't in the oil nor oil in the coolant. Next up, compression test?

 

mentioned by deserthonda - change the cap (cost is not much)
have seen this before - few times -
this is my guess -
those tops part and bottom part of the rad is plastic - they develop cracks - will seep a little (may not be able to find it by casual look) - the situation that one has is that the pressure is not being kept to what it needs to be - the symptoms that you described is what one would see.

check the plastic part of the rad for a crack

 

Well, it turned out to be an evapoleak, but not in the cap or the radiator housing. I just blew the coolant hose that goes to the fast idle control. It squirted coolant everywhere. Now I have to figure out how to remove the clamp, being that this hose is convieniently located under the fuel rail, next to the intake manifold, beside the bypass hose, and over the thermostat housing.

 

they seem to never make them easy.
think the throttle bodies have more room

 

Well, I got everything replaced, thanks to NAPA convieniently having similar parts. The little coolant hose has a melt blister on one side and the tear is on the end of it. Wonder how that happened?

It was interesting how the car convieniently started to overheat as I approached my street. I was all like "TEMPERATURE OF HEAT IN COOLANT TOO HOT!! MAIN HEATER TURN ON!! ENGAGE NETURAL GEAR! MAIN ENGINE TURN OFF! DRIVE IN HOUSE WITH SPEED! PARK IN STOP!"

I guess I have been reading too many badly translated owner's manuals recently...