Exhaust Hanger Causes Noise Problem for Nissan
This bulletin applies to 2013-2015 Nissan Altima sedan vehicles equipped with a QR25DE four-cylinder engine. A “boom” or drone sensation may be heard in the cabin area and/or vibration might be felt in the floor and/or steering wheel when driving and the engine is at about 1,800 RPM.
Check the gap between the rubber and metal portions of the front tube exhaust hanger. If less than 1mm of gap is found, add shims (flat washers) between the front suspension cross member and the front exhaust tube hanger. Maximum shim thickness should be 4.6mm (0.18 inch).
The minimum gap should be 1.0mm between the rubber and metal portions of the hanger.
If needed, add washer shims between the hanger and cross member. Shim total thickness should not exceed 4.6mm.