I have a 88 honda civic hatch 1.6L DOHC engine, which started overheating. . About 2 Days ago i cleaned out the IACV and the throttle body. Im not sure if that has anything to do with it, however that was the last work i have done to it. I used the car to deliver pizza last night and It started. It would jump up, then slowly go down. It would be running normal temp for a bit, then slowly incline. Any suggestions on where to start?

 

Most importantly, are you losing coolant?
Secondly, is the coolant level good in the radiator and the overflow bottle?

If you are not losing coolant and your level is good, make sure both of your fans are working. If both fans are working, look into replacing the thermostat. Go from there and see where that gets you.

 

What he said ↑↑↑↑
ALSO:

READ THIS THREAD
https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/91-crx-overheating-issue-3194614/
Particularly the information regarding the thermostat and the air bubbles.

 

Air pockets can cause all kinds of problems in the cooling system. Purging them should be a top priority.

Temperature fluctuations point to a thermostat that is out of range. Does you car still produce heat inside?

 

I Believe it is the head gasket. It seems to be loosing coolant. I refilled it with rad fluid, and purged it and it seems to be working for a bit. I had to add more about 3 weeks later. I know what this means The car produces heat once i purge the Rad.

 

You can do a compression test to be sure, but if you are losing coolant and don't see leaks, the head gasket is the likely cause. Fear not. A head gasket job on a d15 is actually pretty easy and can be done in about 6 hrs.