car is a 1996 Honda Civic EK hatchback. B16A2 DOHC VTEC engine. Currently has 204,000 kilometres (127,000 miles)
When the car is on a stop and idling, the temp gauge needle goes up steadily, and when the car is running, the gauge goes back to normal just as fast. When the temp gauge is on hot and I rev the engine, temp gauge needle goes down a little bit. Fan switches on on Hot reading, then turns off when the needle goes down a bit, still the engine is not smoking nor does it feel really hot. It's just a normal temperature as far as I can tell.
Hood is warm, valve cover/rocker cover is hot but does not burn my hand when I touch it.
Overflow tank literally overfilled, I saw coolant stains around the overflow tank, on the fan shroud, and on the transmission case, then the next morning the overflow tank is empty probably due to the vacuum caused, hence the coolant inside the tank was sucked back in.
Thermostat was replaced with an OE replacement, but I do not trust this new thermostat, that is why I bought an OEM Honda thermostat. Still waiting to be installed.
Waterpump and timing belt, tensioner is also due for replacement.
Radiator was also replaced with an aluminium one, which is much thicker compared to OEM, however the coolant has not been replaced since it still looks good and I also bled the coolant for one hour. Although, the coolant still was bubbling after an hour of bleeding. When I rev the engine when bleeding, bubbles were present and at the same time coolant was boiling.
Hoses are old, but no signs of leaks. Coolant is not contaminated with oil, and oil on the dipstick and oil cap does look normal, no milky substance. Car does not blow white smoke. Hoses are both hot when fan switches on
When the car is running, and when A/C is turned off, windows closed, I can feel a little bit of heat coming out of the A/C vents (speed was about 60-80kph or approx. around 45 to 55mph)
Trusted mechanic said the engine sounds healthy but he did not perform any inspections, just a quick check since my car was not booked for servicing/repairs.
I will do all the servicing in one go as much as possible. Headgasket is also a suspect here but no compression tests have been done yet. No leaks except near the distributor and VTEC solenoid.
Anyone know what problems the cooling system have?