Car makes "gurgling" noise when accelerating
 

Car's an 02 civic ep3 with 207000kms. Everything seems to be fine, but under hard acceleration or going up hills sometimes this "gurgling" noise will show up from right side of the car. This usually only lasts for a few brief seconds though. I don't know how else to describe it, but it sounds like fuel being injected really hard, as if something is clogged in there, or someone taking a straw into a vat of liquid and blowing through it. Primitive description I know.

Anyways, I got a mechanic appnt tmr, but I was wondering if the RS forum can offer any insight as to what it could be.

I used some 89 octane fuel just to see, and it made it better, but it still comes up.

Note, I have heard this sound coming from other cars so I know its a pretty common occurrence.

cold air intake induction noise before hitting vtak?

Probably the cooling system vs the injection / fuel system. The section behind the console which provides you with heat too.

Is it the coolant reservoir gurgling? If it is could be a head gasket going.

I think it was mostly the coolant. Flushed and replaced coolant, changed the oil and filter and with the higher octane fuel, the noise seemed to have gone away completely (for now).

On a side note, secondary o2 sensor has gone bad. Anyone know a good place to buy a (cheap) o2?