Hi all, I have a 2000 Civic D16y7, 200k miles, auto, that is giving me issues with not actually overheating but getting about 3/4 the way up on the temp gauge.
So Im in the south, and in the mornings its about 80 degrees and I have no issues (on the same note, traffic isn't as bad in the am either)
On the ride home (same distant obviously, more traffic though so longer times at stop lights + high 90's/low 100's degree weather) Towards the end of my 30 min commute, the car will slowly climb up the temp gauge at red lights.
Driving keeps the temp dead set in the middle of the gauge w/o issue.

Now I have bleed the cooling system (jacked front end of car up, turned heat gauge to hot, let car idle with radiator cap off for 2 cooling fan cycles)

Installed New Radiator cap (non oem gates brand)

Ive also tried putting the car in neutral at a redlight when the temp is rising and rev the engine, temp doesn't seem to go down. As soon as I pull off from the light though it immediately drops to normal temp, well within a couple hundred yards.

Both upper and lower radiator hoses are hot and I can press my fingers/hand into them.

It doesn't appear to me to be a hg issue (no milky oil, no loss of power, etc)
but to be fair, no block tester or compression tests have been done.

Any ideas? Im stumped. I figured it was an trapped air pocket, but no luck, Ive bled it twice and doesn't seem to be helping.

 

Does the radiator fan work? Jump the thermal switch on the thermostat housing and the fan should run all the time the key is on (if it doesn't run all the time the key is on, troubleshoot the fuse, motor, and relay). Test drive with the fan running all the time. If no overheating, replace the thermal switch.

 

Replace thermostat and check to make sure the fan is coming on when the car is hot.

Thermostat is the first thing to replace, burp the system after replacing it. Remember to turn your Heater on after you fill your system when you are burping it

 

Fan is coming on but it only runs for 30 seconds or so, and goes right off, then 2-3 mins later it'll go on and run for 30-45 seconds (at least during bleeding thats how it happened)....I can try jumping it tonight and drive it jumped for a bit.

 

Fan is definitely coming on ---
Ill replace the thermostat either way b/c they are cheap, but Im exactly sure how'd it be related to my issue (trying to learn more about cars) unless it was stuck open / closed?

 

Thermostat is a large spring with a disc on it. At operating temperature the spring opens and let's the cold coolant in from the radiator.

If your thermostat is not opening fully it would prevent the cooled liquid from entering the engine.

The thermostat was designed to get your car up to operating temperature as quickly as possible. When it fails or becomes faulty it can cause the car to over heat because it does not allow the cooled coolant that's already passed the radiator into the engine