What motor mounts do and why they fail

Motor mounts are rubber-and-metal pieces that hold your engine to the frame and absorb vibration as it runs. When they wear out, you'll feel the engine shaking through the steering wheel or floor, hear clunking when you shift into gear, or notice the engine moving visibly under the hood. A failed mount can let the engine move enough to damage hoses, belts, or the radiator, so replacing them before that happens saves money.

Most vehicles have three to four mounts — one on each side, one at the front, and sometimes one at the rear. They typically last 5 to 10 years depending on driving conditions and how much engine vibration your vehicle produces. A rough idle, towing, or frequent hard acceleration wears them faster.

Key Takeaways

  • Motor mounts hold the engine in place and absorb vibration; worn ones cause shaking, clunking, and visible engine movement.
  • You will need basic hand tools, a jack and jack stands, and the specific mounts for your vehicle year, make, and model.
  • The job takes two to four hours per mount and requires supporting the engine weight safely while you unbolt the old mount and bolt in the new one.
  • If you are uncomfortable working under a raised vehicle or supporting engine weight, a mechanic can do this work for $300 to $800 per mount depending on location and vehicle type.

Tools and parts you will need

Before you start, gather the correct replacement mounts for your vehicle. Go to a parts store with your vehicle identification number (VIN) — the 17-character code on your dashboard or door jamb — and ask for the motor mounts. Do not guess at which ones you need; the wrong mount will not fit or will leave the engine misaligned.

You will also need a socket set, wrenches, a floor jack rated for your vehicle's weight, jack stands, and wooden blocks to place under the engine if you need to support it directly. A hoist or engine support bar (a metal rod that bolts to the engine and rests on the frame) makes the job much safer and is worth renting from a tool rental shop if you do not own one. Do not rely on the jack alone to hold the engine — it can slip and cause serious injury.

Locating and accessing the motor mounts

Raise the vehicle on a jack and find it with jack stands under the frame, never under plastic trim or the oil pan. Consult your vehicle's service manual to find where each mount bolts to the engine and frame; the location varies widely. Some are straightforward to reach from the top of the engine bay, while others require removing the wheel well liner or dropping the subframe slightly.

Take a photo of the old mount in place before you remove it so you can see how it was oriented. Note which bolts go where — engine-side bolts, frame-side bolts, and any spacers or brackets are often different sizes and must go back in the same spots.

Removing the old mount

If you are replacing a side or front mount, support the engine weight first. Use an engine support bar bolted to the engine, or place a wooden block under the oil pan and carefully raise the jack until it just touches the block — do not lift the engine, just take its weight off the mount. This step is critical: the engine is heavy, and if the mount breaks while you are working, the engine can drop and cause injury.

Once the engine is supported, unbolt the old mount from both the engine side and the frame side. Some mounts have a single bolt, others have two or three. Keep the bolts in order — take a photo or lay them out in the sequence they came out. Remove the old mount and 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 have a machine shop re-thread it.

Installing the new mount

Position the new mount so the bolt holes line up with the engine and frame. Hand-tighten all bolts first — do not fully tighten them yet. This lets you shift the mount slightly if the holes do not line up perfectly. Once all bolts are hand-tight, tighten them in a cross pattern (like tightening wheel lugs) to may support even pressure. Tighten to the torque specification in your service manual; over-tightening can crack the rubber or strip the bolts.

Lower the engine back onto the new mount by slowly releasing the jack or support bar. The engine should settle smoothly without any grinding or binding. If it does not, stop and check that the mount is seated correctly and all bolts are tight.

Checking your work and testing

Before you lower the vehicle completely, start the engine and listen for any new clunking or grinding sounds. Shift into Drive and Reverse a few times while parked — you should feel much less shaking than before. If the shaking is gone but you hear a new clunk, a bolt may be loose or the mount may not be fully seated. Turn off the engine, support it again, and check all bolts.

Lower the vehicle, tighten the lug nuts if you removed a wheel, and take a short test drive on a quiet road. The engine should run smoothly without excessive vibration through the steering wheel or floor. If you replaced multiple mounts, the improvement will be noticeable.

When to call a mechanic instead

If the bolt holes in the engine or frame are stripped and cannot be re-threaded, if the engine is difficult to support safely in your workspace, or if you do not have a service manual for your vehicle, a mechanic is the safer choice. Motor mount replacement is straightforward work, but it requires careful attention to engine weight and bolt torque. A mistake can damage the engine or create a safety hazard.

Most independent shops charge $300 to $800 per mount including parts and labor; dealerships typically charge more. The cost varies by vehicle type, location, and how many mounts need replacement. Getting a quote before you start your own work helps you decide whether to proceed or hand the job off.

Frequently Asked Questions

Can I drive with a bad motor mount?

Yes, but not safely for long. A failed mount lets the engine move enough to damage hoses, belts, and the radiator. The shaking can also make the steering wheel hard to control. Replace it as soon as you notice the symptoms.

Do I have to replace all the mounts at once?

No. Replace only the ones that are worn. However, if multiple mounts are old, replacing them all at once saves labor costs because you do not have to raise and support the engine multiple times. Ask a mechanic to inspect all of them first.

What is the difference between a solid mount and a rubber mount?

Rubber mounts absorb vibration and are standard on most vehicles. Solid mounts transfer more vibration to the frame and are used mainly on performance or racing vehicles. Stick with rubber mounts unless your vehicle was designed for solid ones.

How do I know which mount is bad if the engine is shaking?

Have someone watch the engine from the side while you shift into Drive and Reverse. The engine should move slightly but not excessively. Excessive movement in one direction points to the mount on that side. A mechanic can also diagnose this by inspection.

Do motor mounts affect fuel economy?

Not directly. However, a severely worn mount can cause the engine to misalign, which may affect how the transmission shifts or how the cooling fan operates. Replacing worn mounts restores normal engine position and function.