2005 Mazda 3 4 cyl Front Wheel Drive Automatic 61,000 miles
When the car is moving at 30-40 klm and at approx 1500 revs there is a bubbling sound in the front of the car. If you go slower or faster it stops. It doesn't make this noise if you are in nuetral and get up to that speed going down a slope. The noise isn't there either if you have the car stationary and just get the revs up to 1500. It is not overheating. No loss of fluids any where.