I recently replaced my thermostat because it was partly stuck open but another issue I am unsure of is a mix of 2 issues.

1. my radiator coming for the block is warm/hot and the one going to the thermostat is usually coldish, normal? also when running the heater my temp drops from normal to the bottom of the cold mark and will stay there regardless of weather

2. the radiator fan comes while parked and I let the car warm up, it comes on after maybe 7-10 minutes and stays on waited 5 mins and its still on but it does shut off when car is off. so my question is what is the normal fan operation?

 

Did you bleed the cooling system?

https://honda-tech.com/honda-civic-d.../#post38664177

 

yes I cracked opened the bleeder valve until coolant came out of it.

 

Did you read the complete procedure?

 

That is only the first step in bleeding. You have more to do to bleed the cooling system.

x2

 

i will do it again. but the car does not overheat and i drive from Tacoma to seattle 5 days a week. i was just wondering why the car is usually on the cold side. I noticed a drop in mpg and i read about the car not being up to temperature could drop mpg

 

Given that you replaced the thermostat, do a proper bleed and go from there.

 

i bleed it again. still the same. heater core hoses warm, return hose from block warm, hose to thermos housing cold. when i squeeze the hose the coolant would move, so i assume theres not a block?

 

 

but the radiator fan never goes off it just stays on after a certain temp and never goes off while parked, and with the heater on max and blower on the temp drops to cold mark and never recovers but the heater blows hot

 

You need to follow the instructions at the link.

 

disconnect the heater hoses? i was reading the first diagram?

 

Read carefully. The procedure has no hose disconnection.

 

my driveway is at a slope. I parked it with the frond end pointing up, I then open radiator cap and open the bleeder. Than i pour coolant into the radiator until coolant comes with no bubles. i refill coolant till full put cap on till first turn run the car till it warms up and did this three times.

 

You're missing at least one part of the procedure.

 

i also tighten the bleeder when after i pour the coolant

 

i put the heat on red also

 

sorry i forgot to put those in but i did exactly as stated in the diagram

 

Did you buy an OEM thermostat from Honda?

 

no i bought it from o reilys, but it was cold bottom hose and hot top hose before i changed it to. so if u leave the cap off and squeeze the hose the coolant moves. also when the cap is off and you rev the car up coolant comes out of the top, normal?

 

How many times did your fan cycle during the coolant bleeding procedure?

 

it doesn't cycle, it comes after temp is reached and stays on till the the car is shut off. but I found out when I tightended the thermostat bolt down it snapped. I got it out but I need to the junk yard to replace

 

Do you have a laser thermometer? If you don't, go buy one - they're like, $10 or $15 at Sears. Start the car, and point the thermometer at the radiator hose nearest the thermostat housing. Record the temperature when the fan kicks on, and then record how low it goes after 2, 5, and 10 minutes of running. Tell us those numbers. When was your thermostat last replaced, and was it replaced with a new OEM unit, or a parts store thing?

 

 

Thank you Tomcat. OP, get a new thermostat from your local dealership. Parts store thermostats are surprisingly unreliable, and your thermostat might be opening at the wrong temperature.