my girl has a 99 civic ex with about 200,xxx miles on it. i have changed the thermostat and fan is on. the car constantly has air bubbles in it when i bleed it. when the car overheats the coolant shoots up out of the resevoir. the radiator cap is new too. there is no smoke or sweet smell. oil seems fine nothing milky in there.

can a bad water pump cause air bubbles to seep into the cooling system? help me out man... thanks. car will start to overheat but then when i turn on the heat it goes down for a bit untill it finally gives in and overheats. oh yeah, i constantly have to refill the car with coolant because it seems to be going out fast. refills about every 2 days. i think it's the pump but then i don't want to hear it's the headgasket.

 

Perhaps its time for new radiator. Have you previously replace the radiator?

was the water pump replaced when the timing belt was done?

 

check the seat of the raditor cap. It could be a blown headgasket letting air into to the system. I bad water pump would not cause air in the system. gl

 

the radiator should be fine... there's no leaking or anything. the pump i believe needs to be replaced but could a faulty pump cause air bubbles in my cooling system?

 

i'm going to get the car's compression tested soon so i can tell if the gasket is bad or not. i hope it's not.

 

i would say the water pump too but try bleeding the cooling system i have heard suggestions to jack the front of the car up and bleed the system.

 

Why are you so quick to rule out the radiator?

I would get a pressure test of your cooling system to see if it is holding pressure.

If it's holding pressure then it sounds like it might be the radiator because your cars cooling systems seems to be overtaxed... but when you turn on the heater (basicallly adding another small radiator) then your car cools off a little.

After time, radiators get gunked up clogged and stop working as efficiently as they used to.

It's very possible, that you need a new radiator.

Usually when water pumps start to fail, they have a "weep hole" that starts leaking water.

So if you are not leaking water, and you are overeheating even when the fan is on, but turning the heater on solves the problem, I would start looking at the radiator.

If it's not holding pressure, then I would start looking for small leaks, and consider a blown head gasket.


Modified by Crazydave at 2:35 PM 5/15/2008