What motor mounts do and why they fail

Motor mounts are rubber-and-metal pieces that attach your engine to the frame and absorb vibration as the engine runs. When they wear out, your engine rocks side to side when you accelerate or shift gears, and you'll feel a clunking sensation under the hood. A worn mount can also let the engine move enough to damage hoses, belts, or the radiator fan.

Most vehicles have three to four mounts—one on each side, one at the rear, and sometimes one at the front. They typically last 5 to 10 years depending on driving habits and road conditions. Heat, constant vibration, and oil leaks all speed up the breakdown of the rubber. You can replace one mount or all of them at once; many shops recommend replacing them together since they wear at similar rates.

Key Takeaways

  • Motor mounts are rubber-and-metal pieces that hold the engine in place and absorb vibration; worn ones cause clunking and engine rocking during acceleration.
  • You will need basic hand tools, a jack and jack stands, and a way to support the engine weight while removing the old mount—either an engine hoist or a wooden block under the oil pan.
  • The job takes 1 to 3 hours per mount depending on location and your experience; some mounts are easier to reach than others.
  • The most common mistake is letting the engine drop onto the oil pan or other components while the mount is out, which can cause expensive damage.
  • If the engine has moved far enough to damage hoses or belts, those repairs will add time and cost beyond the mount replacement itself.

Tools and materials you'll need

Gather your tools before you start. You'll need a socket set (typically 10mm to 18mm), wrenches, a jack, jack stands rated for your vehicle's weight, and a way to support the engine. An engine hoist is the safest option, but if you don't have one, a wooden block (4x4 or thicker) placed under the oil pan works for most jobs. Do not rely on the jack alone—it can slip or fail, and a falling engine causes serious injury and thousands of dollars in damage.

You'll also need the replacement mounts themselves. Get the exact part number from your vehicle's manual or a parts store using your year, make, and model. Some mounts come with new bolts included; others don't. Check the package before you start so you're not halfway through the job when you realize you need hardware.

Locate the mounts and plan your approach

Open your hood and look at the engine bay. Motor mounts are bolted to the frame or subframe on one side and to the engine block on the other. You'll see a rubber piece with metal brackets on both ends. Your vehicle's manual shows the exact location of each mount and the bolt sizes. Take a photo of the old mount before you remove it so you know how to position the new one.

Some mounts are straightforward to reach from the top of the engine bay; others require you to work from underneath or remove other components like the air intake or radiator hose. Check your manual for any parts you need to move out of the way first. If the job requires removing the wheel well or bumper, factor that into your time estimate.

Support the engine and remove the old mount

Raise the vehicle on jack stands—never work under a car supported only by a jack. Once the car is find, position your engine support (hoist or wooden block) under the engine. If using a block, place it under the oil pan with a small jack underneath to lift the engine just enough to take pressure off the mount you're removing. Raise slowly and stop if you hear or feel anything binding.

Unbolt the mount from the frame first, then unbolt it from the engine. Keep the bolts in order—they may be different sizes or lengths. Slide the old mount out. Inspect the bolt holes on both the engine and frame for damage or stripped threads. If a hole is stripped, you may need to use a larger bolt with a washer, or drill and tap a new hole—both are jobs for a shop if you're not experienced.

Install the new mount and lower the engine

Position the new mount so the rubber is centered and the metal brackets align with the bolt holes. Hand-tighten all bolts first so you can shift the mount if needed. Once everything lines up, tighten the bolts in a cross pattern (like tightening a wheel) to avoid twisting the rubber. Tighten to the torque specification in your manual—usually 35 to 65 foot-pounds for engine mounts, but check your specific vehicle.

Lower the engine support slowly and carefully. Watch for any hoses, belts, or wires that might catch as the engine settles. Once the engine is fully resting on the new mount, remove the support and lower the vehicle. Start the engine and listen for clunking or unusual vibration. The engine should feel solid when you shift into gear and accelerate gently.

Replacing multiple mounts in one job

If you're replacing more than one mount, you can work on them one at a time using the same support method, or you can support the engine from multiple points if you have the equipment. Working one at a time is slower but safer because the engine stays supported at all times. Never remove more than one mount at once unless you have a professional hoist system.

After replacing all mounts, take the vehicle for a test drive on a quiet road. Accelerate smoothly and listen for clunking. Shift between Drive and Reverse a few times—worn mounts often show up as a clunk when the engine rocks forward or backward during gear changes. If the noise is gone, the job is complete. If clunking persists, one of the other mounts may also be worn and need replacement.

Common mistakes and how to avoid them

The biggest mistake is letting the engine drop or shift while a mount is out. Always keep the engine supported until the new mount is fully bolted in place. The second mistake is over-tightening the bolts, which can crack the rubber or strip the threads. Use a torque wrench and follow your manual's specification exactly.

A third mistake is not checking whether the old mount bolts are reusable. Some mounts come with new bolts because the old ones are stretch bolts—designed to be used once and then replaced. Using a stretch bolt twice can cause it to fail. If your new mount includes bolts, use them. If it doesn't and your manual doesn't specify, ask the parts store whether the old bolts are safe to reuse.

When to call a shop instead

If your vehicle requires removing the subframe, transmission, or other major components to access a mount, this job moves into shop territory. Some cars also have hydraulic or electronic mounts that require special tools or programming. If you don't have an engine hoist and can't safely support the engine with a block, a shop is the safer choice.

If you discover stripped bolt holes or damage to the engine block or frame during removal, stop and take the vehicle to a shop. Attempting to repair those issues without proper equipment usually makes them worse. A shop can assess the damage and decide whether the hole can be repaired or whether a different mounting solution is needed.

Frequently Asked Questions

How long does it take to replace one motor mount?

Most mounts take 1 to 2 hours if they're easily accessible from the top of the engine bay. Mounts that require working from underneath or removing other components can take 2 to 3 hours. Your first mount will take longer because you're learning the process; subsequent mounts on the same vehicle usually go faster.

Can I drive the car with a bad motor mount?

Yes, but not safely or for long. A worn mount lets the engine move excessively, which can damage hoses, belts, and the radiator fan. The clunking and vibration also make the car uncomfortable to drive and can mask other problems. Replace the mount as soon as you notice the symptoms.

Do all motor mounts need to be replaced at the same time?

Not necessarily, but it's common for all mounts to wear at similar rates. If only one is clearly damaged, you can replace just that one. However, if you're already under the car, replacing the others while you're there saves labor cost in the long run since you won't have to do this job again in a few months.

What's the difference between OEM and aftermarket motor mounts?

OEM (original equipment manufacturer) mounts are made by the car's manufacturer and match the original specifications exactly. Aftermarket mounts are made by third-party companies and are usually cheaper but may vary in durability and vibration control. For a daily driver, a quality aftermarket mount works fine. For a high-performance or older vehicle, OEM is often worth the extra cost.

Why is my engine still clunking after I replaced the mounts?

If clunking continues after replacing one or more mounts, another mount is likely worn. Check the remaining mounts by having someone gently rock the engine in and out of gear while you watch for excessive movement. You may also have damage to engine mounts on the transmission or a separate issue like worn suspension components, which would require a separate diagnosis.