Coolant Radiator

[EK1 Civic]

Hi guys i just drained my coolant out of my car and flushed the radiator. Topped it up with coolant and let it run without the cap. Bubbles started appearing which i heard was normal. Then a tad of foam at the top. My car started to rev and de-rev going from 1800 revs to about 1200 revs and bouncing back and fourth. Is that the fan? or is it not normal? My heater setting is still on hot if it makes a difference now =/ Thanks

I suspect there's still air in the coolant pipes and its causing my idle to bounce.

[EK1 Civic]

bump.

[teh_mechanic]

might be an air bubble around where the coolant goes into the IACV on the throttle body, therefore not allowing the IACV to know the right coolant temp and moderate the idle properly. In any case all you can do really is run it until its hot, let it cool, and repeat over the next few days if it keeps doing it. Theres no real problem in having a few little bubbles in there, just watch your temp gauge when you drive as if there is a large bubble it will overheat

[EK1 Civic]

Gonna try run it again 2morro on my driveway since its inclined, with the cap off the radiator for 30min. Ill just bring my laptop and watch 1-2 tv shows xD

[markismaximus]

Gonna try run it again 2morro on my driveway since its inclined

might be part of the problem. depending on which way the car is facing and the angle of incline it could be stopping coolant from entering the rest of the system. Try filling it on level ground. This applies to most fluids in your car....

[EK1 Civic]

Ok i left the car today on a flat surface. Took the cap off, turned on the car and let it warm up. I squeezed the bottom hose to help air escape from the radiator top, had a total of like 7 bubbles appear. Then i turned on the heater to full blast, no fans came on. So i turned on the a/c with heat on and the fan to the left of the engine bay turned on a total of 5 times. However my engine would continue to rev from 1800 and de-rev to 1200. I havent taken the car for a drive in about two weeks. Could it be with the cap off and it being not driven the pressure is lost that it needs? and taking it for a drive might solve the issue. I've taken off the TB and cleaned out all the things attached to it. I've uploaded a 1 minute video on youtube showing the problem if it helps pinpoint the issue.

You can watch it here http://www.youtube.com/watch?v=mWEqSfq_r-Y

[EK1 Civic]

Solved the issue fellas, ended up being the throttle plate being open during idle like beeza told me. Anyways its fixed and i learnt how to bleed air from the radiator :D Thanks for all your input fellas.