Hi all,

Troubleshooting my brother's '93 Civic hatchback, cant remember the exact model (CX/DX/etc). Replaced all new hoses/thermostat in 2016. Ran fine for over a year after that. Then earlier this year he had overheating issues - bottom radiator hose was cold.

Troubleshooting steps #1:
- checked for leaks (none)
- blew out radiator with fresh water (no blockage)
- checked radiator for leaves/debris blockage (fine)
- radiator fan worked
- upper radiator hose = hot
- lower radiator hose = hot

Re-filled with coolant. Test drive, ~6 miles. Car ran fine, bottom radiator hose was hot. Then my brother drove it a few hours later and temp rose again.

Troubleshooting #2:
- replaced thermostat even though it's <3 yrs old, and topped off coolant.

Test drive 2: car overheated within 1.5 miles. Turned on heat, thermostat climbed HIGHER, which seemed odd. Checked bottom radiator hose - cold.

I forgot to bleed the coolant system, which is my next move. Then test fuses/relays, and temp sensor.

Further suggestions?

Thanks.