2000 Honda Civic LX sedan, manual trans, 161K miles and a fair amount of neglect, but this is my $1000 beater. Car is stock.
Yesterday (Friday night) I was driving around a parking lot and noticed that my coolant gauge was starting to climb. I pulled to a spot and let the car idle, thinking that would help it cool down, however the temps continued to climb on the gauge. I shut the car off, checked the coolant (it looks/smells fine and nearly new, as does the radiator, which was replaced recently), and felt that the lower radiator hose was fairly cool to the touch. It was a hot day, though this was maybe 9 PM, so it had cooled down. I drove home with the heater on (turning it off got the temps up quick) I had heard some air in the coolant system after shutting the car off previously, so I figured I’d burp it. The car never got over the 3/4 mark on the coolant gauge.
I burped the coolant first thing this morning before driving the car and a few bubbles came up. Topped it off after burping and drove to work with zero issues. On my way home from work, after the car had been sitting idle for a couple minutes at a stop light after a freeway drive, the temps started to climb, however it was 100 Fahrenheit outside and the A/C was on. The fan does come on for both the A/C and the coolant system normally. I turned the heat up, temps went down within seconds, turned the heat off a minute later, and the car refused to climb in temperature again. I sat at idle for several minutes when I got home and nothing came of it.
I did notice that, this morning and before I left work, the car required a couple extra cranks to start. It still does now that it’s cooled down, but I can get it started quickly by holding the throttle wide open. I’m worried that I may have cracked the head or damaged the head gasket despite the car not seeing temps all that close to the top of the coolant gauge. My guess is that the thermostat might need replacing, but given that the oil and coolant look and smell fine, are my concerns over the head necessary? Why would the car now suddenly have difficulty starting quickly? Thanks.