Another overheating car... D13B EG

Hey guys. Got a 92 Civic Breeze.

Have had an issue with overheating from the day since i bought it. The problem only occured when either on the freeway doing 80-100km/h or under hard driving. Temperature steadily raised higher from it's original spot just under halfway on the gauge.

Pulled over and checked it, and there was coolant spilling out of the overflow bottle. Temperature dropped back down at idle, so merged back onto freeway. Heated up again, so i put the car into "limp home mode", but found that by turning the climate control over to heater, the car didn't overheat anymore. And it didn't overheat since, jsut by keeping the heater selected(not even running the fan, just having it on the far right on the temp slide).

So from this i figured it must be a blocked radiator, or somewhere in the system. Due to the fact the heater circuit was enough for the car to maintain temp and that the car wasn't losing coolant. Ordered a new radiator, cap, hoses and thermostat. Radiator was an ASI item off ebay and fitted in perfectly.

So just fitted that today. And after bleeding the system up, all seemed good. Temp gauge was sitting at about 1/3. Took it for a drive and came home. All good. Then let it idle and flicked the climate over to the cold setting. Was fine for a while, but then gradually started to climb over the 1/2 mark. Was watching for the fan and it didn't seem to cut in until about 1/2-2/3 of the gauge.

So now i'm wondering where the issue could lie. I haven't taken it on the freeway yet, will be later tonight. So will report back tommorow on anything else i've picked up on. Any ideas?

Sorry for being vague with temperature readings, only have the gauge to go off.

Bump, just drove it home now with heater on. Checked temperatures and got 70 degrees top hose, 40 degrees bottom hose.

Gunna drive to missus place later with the heater on and see how it goes.

Thermostat cracks at around 86 degrees on these, correct?

Well....... Figured it out.

Equipped with my laser thermometer, i've found out that it appears the coolant sensor is rooted, or honda are retarded with their gauge system.

Found that even when the gauge peaked at about 7/8ths of the gauge, the actual coolant temp was only around 80-90 degrees on the top hose, meaning normal operating temp. And the fan was cutting in perfectly.

So gunna have to get myself a workshop manual and test this sender. =D

If it was a faulty gauge, why would coolant be bypassing the pressure release valve on your radiator cap and exiting your overflow bottle.

Take radiator cap off, turn the car on, If coolant spilling outside and you have too much bubbles than you have head gasket problem. If it is allright than change your radiator cap,and check.

Confirmed to be all good! So the radiator was the original problem as i thought.

Have been testing it with my thermometer over the last 3 days and it is all good. Thermostat cracks at 86 degrees(about 3/4 of the gauge), which travelling to and from work i never even hit, getting to temps of around 76 degrees in the daily commute.

I will be testing the sensor for the gauge in the future, but for now. All is well. =D

As for the comments, thanks guys. Coolant only exited the overflow bottle with the old radiator, due to the blockage. No issue with that now. And at no point did the car ever blow smoke or lose coolant, so definatly not a headgasket issue, knew that from day 1.