KA24DE won't heat up

[Taylor008]

Clutch fan, bled coolant properly three times, 75/25 water/coolant mix. S13.

New water pump, new thermostat.

I start the car and let it run, if I just let it idle it will take forever (about an hour) to get up to the middle(normal) of the temp gauge. Once I start driving, the temperature drops down to the very bottom and won't heat up again until I'm idling for another 30 mintues or so.

Any ideas? I'm all out of them. I don't think its the gauge coolant temp sensor because it will display that it is warm until I start moving.

I've searched and almost all threads are overheating, not underheating... Even tried googling but most things point to a stuck thermo. Replaced, same problem. Help!

[DinoMan]

Are you sure its not your temp sensor? unless your thermo is stuck open and doesnt close i dont see why it would be UNDERheating

[Mishkin_707]

could be your coolant temp sensor, after 10 minutes turn your heater on to see if that's warm/hot if not it has to be the thermostat, you sure you didn't put them in backwards?
or maybe the "new" water pump is defective?

i know when my thermostat went bad it was doing the same thing you just explained, it would take forever (40-50 minutes) to show anything on my gauge but as soon as i turned my heater on my temp gauge would go back to cold, same thing if i drove, it the temp gauge went back to cold, could be one of the three things i mentioned.

it was such a pain in the ass, just do the first thing i told you, it's the easiest, if no then either your thermostat is backwards or defective, could be possible that your water pump isn't working.

also make sure your belt is tight, hey you never know?

[JDM_PILOT]

yaa bro. when your engine heats up its not going to Underheat. yaa i would double check that gauge or replace it if yu can just to eliminate the factor. uhhm or have you lookd at your 02 Sensor?

[s14fbs]

its either 2 things
your therm is bad which if its a cheap advanced one thats very possible i have had them be bad right out the box and its stuck open or installed backwards but that should cause u over heating problems

or your temp sensor has gone bad or going back

imo i would get yourself a prosport of glow shift, auto meter w/e just a cheap quality water temp gauge cause the ka oem cluster gauge are not really worth much but a dummy gauge cause there very very inaccurate

and ka don't like heat they go pop

[One_love_silvia]

what kind of thermostat do u have?