What engine mounts do and why they fail

Engine mounts are rubber-and-metal pieces that hold your engine to the frame while absorbing vibration as it runs. Over time — usually between 5 and 10 years — the rubber cracks, hardens, or separates from the metal, and the engine starts to move too much. You'll notice this as a clunking sound when you shift into gear, excessive vibration through the steering wheel or seat, or visible engine movement when you look under the hood while someone revs the engine in park.

A failed mount doesn't leave you stranded, but it stresses other engine components and can eventually damage transmission mounts, hoses, or belts. Replacing mounts before they completely fail prevents that cascade of problems. The job ranges from straightforward on some vehicles to labor-intensive on others, depending on which mount has failed and how much of the engine bay you need to access.

Key Takeaways

  • Engine mounts typically last 5 to 10 years and fail when the rubber separates or cracks, causing clunking sounds and excessive vibration.
  • You'll need a jack, jack stands, basic hand tools, and a replacement mount specific to your vehicle's year, make, and model.
  • The process involves supporting the engine weight safely, unbolting the old mount, and installing the new one in reverse order.
  • Front and side mounts are usually accessible from above or below; rear mounts often require removing the transmission crossmember or exhaust components.
  • If you're uncomfortable working under a running engine or lifting a vehicle, this job is better left to a shop.

Gather the right tools and parts before you start

You'll need a floor jack rated for your vehicle's weight, a set of jack stands, and basic hand tools: a socket set, wrenches, and a breaker bar for stuck bolts. Some mounts require a transmission jack (a smaller, specialized jack that supports the transmission pan) to keep weight off the new mount while you bolt it down. Check your vehicle's service manual to see which type of jack you need.

Buy the replacement mount before you start. Engine mounts are specific to your vehicle's year, make, model, and engine size — a mount for a 2015 Honda Civic won't fit a 2015 Honda Accord. Order from a parts supplier using your vehicle identification number (VIN), or bring your old mount to a parts counter and have them match it. OEM (original equipment manufacturer) mounts last longer than aftermarket ones, but both are available.

Disconnect the negative battery terminal before you begin. This prevents accidental electrical shorts when you're moving components around the engine bay.

Support the engine safely before removing the old mount

The engine's weight is distributed across three to four mounts. When you remove one, the others must carry the load temporarily, and you need a jack to prevent the engine from dropping. Position your floor jack under a solid part of the engine block or oil pan — never under plastic covers or thin metal. Raise the engine just enough to take tension off the mount you're replacing; you should be able to move it by hand but not so much that you're lifting the whole engine off its other mounts.

Place jack stands under the frame or subframe on both sides of the vehicle, set to a height slightly lower than the jack. This is your safety net: if the jack fails, the stands catch the vehicle. Never work under a vehicle supported only by a jack.

Once the engine is supported, locate the mount you're replacing. Front mounts are usually visible from above or from underneath the front bumper. Side mounts (also called torque struts) connect the engine to the frame on the side. Rear mounts sit between the engine and transmission or between the transmission and frame. Your service manual will show you exactly where yours is.

Remove the old mount and install the new one

Unbolt the mount from the engine block first, then from the frame or subframe. You may find one, two, or three bolts depending on the mount type. Use a breaker bar if bolts are tight; penetrating oil (like PB Blaster) applied 10 minutes before helps. Keep bolts organized — they're often different sizes and lengths, and putting them back in the wrong holes can cause misalignment.

Slide the old mount out. If it's stuck, gently pry it with a flat pry bar, but don't force it — you risk bending the frame or engine block. Once it's free, compare it to the new mount to confirm they're identical. Check that rubber bushings on the new mount are intact and not pre-compressed.

Position the new mount and hand-tighten all bolts first. This lets you align the mount properly before you torque them down. Then tighten to the torque specification in your manual — typically 40 to 80 foot-pounds depending on the mount. Tighten in a cross pattern if there are multiple bolts, just like tightening wheel lugs, so the mount sits evenly.

Lower the engine and check your work

Once the new mount is bolted down, slowly lower the jack while watching the engine. It should settle smoothly onto the new mount without tilting or shifting. If it tilts, stop, raise it again, and check that all bolts are tight and the mount is seated correctly. Remove the jack stands, then lower the jack completely.

Reconnect the negative battery terminal. Start the engine and listen for clunking or grinding sounds. Shift into Drive and Reverse a few times while parked — you should feel smooth engagement without the clunking you heard before. Take a short test drive on a quiet road and listen for vibration or noise.

If you replaced a front mount and the steering wheel still vibrates, or if you hear clunking from a different location, another mount may also be failing. This is common; mounts often wear out together. Have a shop inspect the others if symptoms persist.

When to stop and call a shop

Some mounts are accessible in 30 minutes; others require removing the exhaust, transmission crossmember, or suspension components and take several hours. If your vehicle's manual shows that the mount you need to replace requires removing the transmission or major suspension work, the labor cost at a shop is usually worth it. Mistakes during those steps can damage expensive parts.

Also stop if you're uncomfortable lifting a vehicle, working under an engine, or torquing bolts to specification. A shop has a lift, specialized tools, and insurance if something goes wrong. A DIY mistake — like over-torquing a bolt and cracking the engine block, or under-torquing and having the engine shift — costs far more to fix than paying a technician upfront.

Frequently Asked Questions

How do I know which engine mount is bad?

Have someone rev the engine while you watch from outside the vehicle. A bad mount lets the engine rock visibly side-to-side or front-to-back. You can also feel where clunking comes from: front mounts cause noise when shifting into gear, rear mounts when accelerating hard. A shop can confirm with a visual inspection.

Can I drive with a bad engine mount?

Yes, but not for long. A failed mount stresses the transmission, hoses, and belts. Vibration can eventually crack engine block coolant passages or damage the transmission. It's safe to drive to a shop, but don't ignore it.

Do all engine mounts fail at the same time?

Not always, but they wear together. If one has failed, the others are usually close behind. A shop inspection of all mounts during the repair can catch others before they fail and save you a second trip.

What's the difference between OEM and aftermarket mounts?

OEM mounts are made by the vehicle manufacturer and typically last longer and dampen vibration better. Aftermarket mounts are cheaper but may harden faster or not fit as precisely. For a vehicle you plan to keep long-term, OEM is worth the extra cost.

Do I need to replace all mounts at once?

Only replace the one that's failed, unless a shop inspection shows others are cracked or separated. Replacing all four at once is more expensive but eliminates the chance of another failing soon after. It depends on your vehicle's age and mileage.