Recently got a 98 Civic DX replaced the head gasket, radiator because the plastic was pretty much shattered, distributor, etc. I noticed the fan not coming on after idling for quite some time even though the temp gauge was midway or slightly less. I have a cheap obd2 scanner tool and it displayed engine temp around 136*F I have no idea what the temp setting is for the radiator switch to activate..

The fans do work when hard wired directly to the battery. I'm concerned because I'm pretty sure the head gasket and radiator went on the previous owner due to overheating

 

Bleeding the cooling system may take 20-30 minutes.

1) Park the car on an inclined driveway with the front end higher than the rear.

2) Push/turn the dash heater lever/**** to MAX heat. Fan need not be on.

3) Follow the directions in the diagram below

 

the temperature for the motor should be between 140 to 180 degrees you will be fine at 136

 

No, that's not right. This is from the service manual:



But back on track, it sounds like there's air in the cooling system. Do the bleed.

 

usually when the thermostat opens, the fan comes on.

 

sensor by the thermostat is where the fan get signal to turn on and off.

 

Typically the fan comes on about 205 F or so, most likely at idle if the car is running for awhile, esp stop and go.

The normal operating temp is about 170 degrees, after the thermostat opens.

 

Where do you get your information?

 

I ran a scan gauge on my car watched in idle as it approached 205 the fan kicked on.

Watched the temp as driving normal temp was 170ish. My ex has a 170 temp thermostat.

This is going by experience.

 

Here's how you should edit your original post:

The point is that you have posted your personal experience, but there is actually a range of normal temperatures, depending on car and conditions. For example, my engines when warmed up run in the range of 195-204F, depending on the conditions.

 

Air in the line seems like the most logical explanation. I had this same problem in my GMC Truck. I bled the lines, as the diagram Ron showed, and it worked fine. Another problem could obviously be leaks. If the thermostat isn't stuck(and it's not according to your findings) check all your hoses and also check your water pump. I haven't had the pleasure of changing a water pump on any hondas but it was fairly simple on my truck. Good luck none the less!