A harsh thump when shifting into Drive, a steering wheel that shakes at a stoplight, or an engine that seems to jump when you accelerate can make an otherwise dependable vehicle feel alarming. Learning how to replace engine mounts starts with understanding that these parts carry far more responsibility than their small size suggests. They support the engine’s weight, control movement under torque, and help keep vibration out of the cabin.
For some vehicles, an engine mount replacement is a manageable repair with the right equipment and experience. For others, especially tightly packaged all-wheel-drive vehicles and many Subaru models, access can be limited and the job can quickly become more involved. The goal is not simply to install a new mount. It is to support the engine safely, replace the correct failed component, and confirm the drivetrain sits in its intended position afterward.
What Engine Mounts Do and How They Fail
Most vehicles use several mounts to secure the engine and transmission to the vehicle’s frame or subframe. A typical setup may include upper and lower engine mounts, a transmission mount, and a torque mount or torque strut. Their designs vary by vehicle, but many combine metal brackets with rubber or hydraulic-filled sections that absorb normal engine vibration.
Rubber mounts can crack, separate, or compress with age, heat, oil contamination, and repeated stress. Hydraulic mounts can leak fluid and lose their ability to control vibration. On a high-mileage vehicle, more than one mount may be worn at the same time, even if only one is visibly damaged.
Common warning signs include increased vibration at idle, a clunk when accelerating or braking, a noticeable lurch when changing gears, and movement of the engine when the throttle is applied. These symptoms are useful clues, not a complete diagnosis. Similar noises can come from worn suspension bushings, exhaust contact, drivetrain issues, or loose components. A proper inspection matters before ordering parts.
Before You Replace Engine Mounts, Confirm the Diagnosis
A visual inspection can reveal obvious trouble, such as torn rubber, a collapsed mount, missing hardware, or fluid leaking from a hydraulic mount. Technicians also look for shiny contact marks where the engine, exhaust, or other parts have shifted and begun rubbing.
Do not rely on a quick test where someone revs the engine while the vehicle is in gear. That can be dangerous if the vehicle is not properly secured, and excessive throttle can stress already worn components. A controlled inspection from a trained technician is the safer approach, particularly when a mount is located beneath the vehicle.
It also helps to consider the pattern of the complaint. Vibration that is strongest at idle but improves as RPM rises may point toward a failed hydraulic mount. A sharp clunk during takeoff and braking may indicate a torque mount or lower mount. If the check engine light is on, the engine runs rough, or the vibration changes with engine speed regardless of vehicle movement, an engine performance issue may be contributing as well.
Tools and Safety Equipment for the Job
Replacing an engine mount requires more than a basic socket set. The engine must be supported while one of its supports is removed, and lifting it incorrectly can damage oil pans, transmission housings, hoses, wiring, or exhaust components.
For a typical repair, the needed equipment may include a vehicle lift or quality jack stands, a floor jack, a wide wood block or engine support bar, metric sockets and wrenches, extensions, a breaker bar, a torque wrench, and manufacturer-approved replacement hardware where required. Penetrating oil can help with corroded fasteners, while a pry bar may be useful for carefully aligning a mount.
Never work beneath a vehicle supported only by a floor jack. Never place a jack directly against an oil pan unless the vehicle manufacturer specifically permits that support method and the load is distributed correctly. A wood block can spread the load, but it does not make every lift point safe. The vehicle repair information for the exact year, make, model, engine, and drivetrain should guide the procedure.
How to Replace Engine Mounts Safely
The exact sequence changes from one vehicle to another, but a careful replacement follows the same basic principles.
1. Plan the repair around the correct mount
Identify every engine and transmission mount on the vehicle and determine which one has failed. Compare the replacement part to the original before disassembly. Mounts can look similar while having different bracket angles, stud locations, or hydraulic designs.
If a mount has failed because it was saturated with oil or coolant, address the leak first. Installing a new rubber mount under an active leak can shorten its service life and create the same problem again.
2. Secure the vehicle and create access
Park on a level surface, set the parking brake, and use wheel chocks. Disconnect the negative battery cable if the repair requires removing components near electrical connections, the starter, or wiring harnesses. Raise and support the vehicle safely if access from below is required.
Depending on the mount location, access may require removing an engine cover, air intake duct, battery tray, splash shield, wheel, or underbody panel. Keep fasteners organized, especially when bolts differ in length.
3. Support the engine before removing mount hardware
Place an engine support bar across the fender rails or use an appropriate lifting method specified for the vehicle. If supporting from below, raise the engine only enough to take the weight off the mount. Watch hoses, wiring, axle angles, and the exhaust as the engine moves.
This is the point where experience pays off. An engine can bind against a mount bracket or shift unexpectedly if hardware is removed in the wrong order. Supporting the engine does not mean lifting the whole vehicle with the engine or forcing the powertrain into position.
4. Remove the old mount and inspect surrounding parts
Loosen and remove the mount-to-body, mount-to-engine, or mount-to-transmission bolts as directed by the repair procedure. Some mounts come out as a complete bracket assembly. Others require separating an insulator from a bracket or removing adjacent components first.
Once the old mount is out, inspect its brackets, bolt holes, heat shields, and nearby exhaust hangers. Look for damaged threads, bent brackets, or evidence that another mount is allowing too much movement. If several mounts are equally worn, replacing only the most visibly damaged one may reduce symptoms without fully correcting the issue.
5. Install and align the new mount without forcing it
Set the new mount in place and start all fasteners by hand. Do not use a bolt to pull an engine or transmission into alignment. Slightly raising, lowering, or repositioning the supported powertrain is usually the correct way to line up bolt holes.
Once the mount is seated naturally, tighten fasteners in the manufacturer’s specified order and to the specified torque. Torque values are not interchangeable between vehicles. Some bolts are torque-to-yield and must be replaced rather than reused, so follow the service information for your vehicle.
6. Reassemble and verify the repair
Reinstall all removed components, reconnect the battery if it was disconnected, and lower the vehicle. Start the engine and listen for unusual contact, rattles, or vibration. With the brake firmly applied, carefully shift through the gears and observe for excessive movement or harsh clunks.
A short road test should confirm that the original concern has improved. Check that the exhaust does not contact the body under acceleration and that no warning lights, fluid leaks, or loose panels remain. If vibration persists, further diagnosis may be needed rather than assuming the new mount is defective.
When a Professional Repair Makes Better Sense
DIY work can make sense when the failed mount is accessible, the vehicle is safely supported, and reliable repair information is available. It becomes less practical when the engine must be lifted substantially, the mount sits behind major components, corrosion has seized fasteners, or the vehicle has multiple drivetrain concerns.
Subaru vehicles, for example, can require careful attention to boxer-engine packaging, all-wheel-drive components, and access around the subframe. The right repair is not always the fastest-looking one. It is the one that restores proper alignment without creating a new leak, vibration, or damaged component.
At Best Auto Service Center, ASE-certified technicians can inspect engine and transmission mounts, identify related causes of vibration or clunks, and complete the repair with the right equipment and specifications. That can be especially helpful when a vehicle needs dependable service before a commute, a family trip, or a Pennsylvania inspection.
A failed engine mount rarely improves on its own. If your vehicle is shaking, clunking, or shifting more than it should, schedule an inspection before the extra movement turns a contained repair into damage to exhaust parts, hoses, wiring, or other drivetrain components.