Hiya. Got a 92 Civic that's been giving me crap for about 2 months now.

Story: hit 200k on a 1.5L LX about 2 months ago with a non-factory installed motor (local Honda guys said engine codes didn't match with the VIN), so no idea what the engine mileage is. Until this point, it's driven without any issues. A few days after taking it into the local Honda shop for the usual oil/filter change, it started overheating. It only happened after I was driving for at least 10-20 minutes, and almost never happened on the freeway until last week.

After doing some research, I swapped out the thermostat this last Saturday, and voilas! Ran like new, freeway or road.

Until today. After about 20 minutes on the freeway it began overheating in the same manner as before: temp gauge would spike, then drop back down. When I'd be street driving, it would spike every few minutes, and sometimes would stay at a high temp until I would get to the 40-50 MPH range, then drop back down for a few minutes (before spiking again).

No white smoke on startup, noticeable change in driving from freeway to street (especially when starting from a dead stop). Hasn't started shooting steam yet, but prior to switching out the thermostat, the coolant in the reservoir was audibly boiling (levels have been kept up, air bled, etc etc). When I changed the thermostat, the hose from the therm to the base of the radiator was bone dry, if it helps.

Any help is massively appreciated.

 

check to see if your fan is working. theres a 2 wire brown plug on the thermo housing, jump the connector of the plug with a piece of wire. if not the sensor could be bad.

 

also your radiator cap could be bad. that acts as a vent for your radiator to go to/from the overflow.

 

sounds like my d15 when the hg was starting to take a dump on me

 

its a possibility that your intake manifold gasket could be leaking.

 

i agree with mooze sounds like the starting of a bad head gasket