What engine mounts do and why they fail
Engine mounts are rubber-and-metal brackets that hold your engine to the frame while absorbing vibration as it runs. Over time—usually 5 to 10 years—the rubber hardens, cracks, or separates from the metal, and the engine begins to rock excessively when you accelerate, brake, or shift gears. A failed mount lets the engine move too much, which can damage hoses, belts, and the radiator, and makes the whole car feel loose and unstable.
Most cars have three to four mounts: two on the sides (left and right), one at the bottom, and sometimes one at the top. You can replace one at a time without removing the engine, though the job is easier if you have a lift and some mechanical experience. If you hear clunking from the engine bay when you shift into gear, or if the engine visibly rocks when you rev it in park, a mount has likely failed.
Key Takeaways
- Engine mounts are rubber-and-metal brackets that wear out over 5 to 10 years and need replacement when the rubber cracks or separates.
- You can replace one mount at a time by supporting the engine with a jack and block of wood, then unbolting the old mount and bolting in the new one.
- The job requires basic tools—a socket set, jack, jack stands, and wood blocks—but takes 1 to 3 hours per mount depending on location and access.
- Some mounts sit in tight spaces where you may need to remove other parts first, such as the air intake or wheel well liner.
- If you are not confident supporting an engine safely or working under a running vehicle, have a professional mechanic do the work.
Gather your tools and materials
You will need a socket set (metric or standard, depending on your car), a wrench set, a floor jack, jack stands rated for your vehicle's weight, wooden blocks (2x4 or thicker), and the replacement mount itself. Check your owner's manual or a repair guide for your specific car to confirm the mount location and bolt size. Some mounts bolt to the frame with two or three bolts; others bolt to the engine block and the frame separately.
Buy the correct replacement mount before you start. OEM (original equipment manufacturer) mounts are more expensive but last longer and fit precisely. Aftermarket mounts are cheaper but vary in quality. Do not reuse the old mount or attempt to repair it by gluing or wrapping the rubber—a failing mount will fail again quickly.
Support the engine safely before you begin
Raise the car on a floor jack and find it with jack stands under the frame, never under plastic trim or suspension parts. Place the jack stands on flat, level ground and double-check that the car is stable before you work underneath it. Lower the car onto the stands so it rests on them, not the jack.
Next, position a second jack with a wooden block on top under the engine oil pan or a sturdy engine bracket—not on plastic covers or hoses. Raise this jack slowly until it just touches the engine and takes up the weight of the engine. Do not lift the engine off its mounts yet; you are straightforward removing slack so the engine does not drop when you unbolt the old mount. If the engine is not supported, it will hang on the remaining mounts and may damage them or pinch hoses and wires.
Remove the old mount
Locate the bolts that attach the mount to the engine block and the frame. Some mounts have two bolts (one to the engine, one to the frame); others have three or four. Use your socket set to unbolt them one at a time, keeping your hands clear of the engine in case it shifts. Once all bolts are out, the old mount will come free—it may be stuck if the rubber has hardened, so tap it gently with a rubber mallet if needed.
Inspect the bolt holes in the engine block and frame for damage or corrosion. If a bolt hole is stripped or cracked, you may need to drill and re-tap it, or use a larger bolt with a backing plate. If you find damage, stop and consult a repair manual for your car or ask a mechanic—forcing a bolt into a damaged hole can cause more problems.
Install the new mount and torque the bolts
Position the new mount so the bolt holes line up with the engine block and frame. Insert the bolts by hand first to make sure they thread smoothly and the mount sits flat. Once all bolts are hand-tight, use your socket set to tighten them in a crisscross pattern (like tightening a wheel), not in a circle. This ensures even pressure and prevents the mount from tilting.
Tighten to the torque specification listed in your repair manual—this is usually between 35 and 65 foot-pounds, depending on the bolt size and car model. If you do not have a torque wrench, tighten firmly but do not over-tighten, which can crack the new rubber or strip the bolts. Once the bolts are tight, slowly lower the supporting jack under the engine to transfer the weight back to the mounts. The engine should settle smoothly without jerking or dropping.
Check your work and lower the car
Before you lower the car fully, start the engine and listen for clunking or grinding. Rev the engine gently in park and listen for abnormal noise. If the engine sounds normal and the new mount feels solid when you push on it by hand (engine off), you are ready to lower the car. Slowly lower the floor jack, then remove the jack stands and lower the car the rest of the way.
Take a short test drive at low speed in a parking lot. Accelerate and brake gently, and listen for clunking from the engine bay. If the car feels stable and quiet, the mount is installed correctly. If you hear noise or feel excessive engine rock, stop and re-check that all bolts are tight and the mount is seated properly.
When to call a professional mechanic
Engine mount replacement is a straightforward job if you have basic mechanical skills and access to a lift or sturdy jack stands. However, some mounts sit in tight spaces where you must remove the air intake, radiator hose, or wheel well liner first. If your car's layout is unfamiliar to you, or if you do not have a torque wrench to tighten the bolts to specification, have a mechanic do the work. A loose bolt can cause the engine to move excessively and damage surrounding parts.
Also call a professional if you find stripped bolt holes, cracked engine block material, or bent frame brackets. These problems require welding, drilling, or specialized tools that are beyond a home repair. A mechanic can assess the damage and determine whether the engine block or frame can be safely repaired or whether the car needs more extensive work.
Frequently Asked Questions
How long does it take to replace one engine mount?
Replacing a single mount usually takes 1 to 3 hours, depending on how straightforward it is to access and whether you need to remove other parts first. Side mounts are often quicker; bottom mounts may require removing the exhaust or suspension components. If you are doing this for the first time, allow extra time to locate bolts and consult your repair manual.
Can I replace all the mounts at once?
Yes, but it is not necessary unless multiple mounts have failed. If only one or two are bad, replace those and monitor the others. If you replace all of them, the job takes a full day and costs more upfront, but you avoid returning to the job later if another mount fails soon after.
What happens if I drive with a broken engine mount?
A broken mount allows the engine to rock excessively, which can damage radiator hoses, belts, and the transmission cooler lines. It also makes the car feel loose and unstable, especially during acceleration and braking. Driving on a failed mount is safe in the short term, but the longer you wait, the more damage spreads to other components.
Do I need a torque wrench to do this job?
A torque wrench ensures you tighten bolts to the correct specification without over-tightening, which can crack the rubber or strip the bolt. If you do not have one, tighten firmly and evenly in a crisscross pattern, but understand that you are guessing at the final tightness. For a few dollars, you can rent a torque wrench from an auto parts store.
What is the difference between OEM and aftermarket mounts?
OEM mounts are made by the car's manufacturer and fit precisely, with rubber compounds matched to your engine's vibration. Aftermarket mounts are cheaper but vary in quality and durability. Some last as long as OEM parts; others harden and fail within a few years. If cost is not a concern, OEM mounts are the safer choice.