BMW 1 Series: B38 1.5T Three-Cylinder Engine Mount Vibration and Failure (F20 116i/118i)

The B38 1.5-litre three-cylinder turbocharged engine produces inherent first-order vibration from its unbalanced firing sequence. BMW uses hydraulic engine mounts to dampen this vibration, but the mounts are prone to premature failure — typically hydraulic fluid leaks from the mount body. Failed mounts allow noticeably increased vibration to transmit to the cabin, particularly at idle and low-speed cruising. While not catastrophically dangerous, failed mounts place additional stress on gearbox mounts and driveline components. Replacement mounts are relatively inexpensive but require labour to access in the confined B38 engine bay.

• Excessive vibration felt through steering wheel and floor at idle
• Noticeable shudder when engaging drive from park
• Engine visibly rocking when revved in park/neutral
• Clunk when changing between drive and reverse

With engine running at idle, observe engine movement — more than 5–10 mm of visible rocking indicates mount failure. Have a helper rev the engine to 2000 rpm in park while you visually inspect engine movement from the front. Check for oily residue on the engine mount body (hydraulic fluid weeping). Both driver and passenger side mounts should be replaced together.

$500 to $1,600 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Have the engine mounts been replaced?”
• “Is there any vibration at idle or when putting the car in drive?”
• “Has there been any inspection of the engine mounting points?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.