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"Bubbling" Noise on Acceleration?

My honda makes a kind of “bubbling” noise during acceleration and I’m wondering if this is normal engine operation noise, or if there is something wrong?

There’s probably air trapped in the cooling system, and you hear it in the heater core when accelerating.

Locate and open the bleed screw for the cooling system, and add coolant to system until all the air is purged from the cooling system.


Not all Civics have the air bleed screw. (My 1999 does not, even though the Haynes manual shows it.)

Turn the heat control to Hot. This opens the valve on the firewall so there’s no restriction between the engine and the heater core. Engine cold, open the radiator and make sure it’s topped up. Also make sure the overflow tank is filled midway between the high and low marks. Close it up. Drive normally for a few days then, engine cold, check that the rad is still full. Top up the overflow tank.

If you still are hearing the sound, drive the car (cold) up on ramps and run the engine with the rad cap off for a good while. Some air may come out. Catch and dispose properly any coolant that spills. If there’s ongoing bubbling at the open rad, that indicates combustion gasses are in the cooling system, and further diagnosis is needed. With luck that’s not the case, and after you’ve run it for a while with the cap off, recap it. Drive off the ramps and check the coolant level after it’s cooled down. Top up rad and tank; check levels in both after a few days driving. And good luck.

Good ideas above. One caution, sometimes folks describes sounds with differing terminology. “Bubbling” to one might be “rattling” to someone else. If it sounds at all like rattling, like if you shake a tin can full of a few nuts, washers, screws inside, if it sounds anything like that, this could be the engine is knocking. I mention this b/c knocking almost always occurs during accelerations, and if that’s the problem it needs immediate remedy as it can damage the engine internals.

1 Like

I also hve honda civic 2004 model 1.7 engine
I just change my power steering pressure hole and since then i hear some king noise from the power steering motor also some noise in the car like air likage

Sorry, I have no idea what this means…what “hole” are you talking about?

To clarify, lift the front of the car via ramps so that the front is about a foot higher than the rear. (At least that is what I think shanonia intends) Be sure to chock all the wheels.

Or park on a steep hill.

Yes. Just the front raised up.

Hose, not hole.