Engine Mounts: Vibration and Clunks

If your car shakes more than it used to at idle, or you hear a clunk when you shift into drive, a worn engine mount may be the reason. Engine mounts are easy to overlook, but they play a big role in how smooth and quiet your car feels. Here's what they do and how to tell when one is failing.

What engine mounts do

Engine mounts hold the engine and transmission in place and connect them to the vehicle's frame or subframe. They also absorb vibration so you don't feel every pulse of the engine through the steering wheel, seat and floor.

Most cars have three or four mounts. Some support the engine, and one or more support the transmission. Mount designs include:

• Rubber mounts, which use a rubber block between metal brackets
• Hydraulic mounts, which contain fluid to dampen vibration more smoothly
• Active or electronic mounts, found on some newer and luxury vehicles, which adjust their stiffness based on driving conditions

Signs of a worn engine mount

Common symptoms include:

• Increased vibration at idle, especially when the car is in drive and stopped
• A clunk or thump when shifting from park to drive or reverse
• Jerking or banging when you accelerate hard or let off the gas
• Visible engine movement. A helper can watch the engine while you shift gears with your foot firmly on the brake. Excess rocking can point to a bad mount.
• Fluid leaks from a hydraulic mount, often a dark or oily residue
• Cracked or separated rubber visible during an inspection

Some of these symptoms overlap with other problems, such as worn CV joints, loose exhaust hangers or transmission issues. A mechanic can inspect the mounts and rule out other causes.

Why engine mounts wear out

Mounts take a lot of stress over their lifetime. Common causes of wear include:

1. Age. Rubber breaks down and hardens over time.
2. Heat. Engine heat speeds up rubber aging.
3. Oil or fluid leaks. Oil dripping onto a rubber mount can soften and weaken it.
4. Hard driving. Frequent aggressive launches put extra load on the mounts.
5. Impacts. Potholes, curbs and accidents can damage mounts or brackets.

Why it matters

A single worn mount may seem like a comfort issue, but it can lead to other problems. When one mount fails, the others may carry more load and wear faster. Excess engine movement can also stress hoses, wiring, exhaust parts and axles.

In rare cases, a completely broken mount can let the engine shift enough to damage nearby components. If you notice heavy clunking or the engine visibly moving a lot, get it checked soon.

What the repair involves

Replacing an engine mount usually means supporting the engine with a jack or support bar, unbolting the old mount and installing the new one. The difficulty depends on the vehicle. Some mounts are easy to reach, while others require removing other parts first.

Mechanics sometimes recommend replacing mounts in pairs or as a set if they're the same age, since a new mount next to worn ones can wear unevenly. Ask the shop to show you the condition of each mount before agreeing to replace them all.

Are engine mounts covered by an extended warranty?

It depends on the plan. Some vehicle service contracts list engine mounts under engine coverage, while others treat them as wear items or leave them out of basic plans. Exclusionary plans, which cover everything except a listed set of exclusions, are more likely to include mounts.

When reviewing a contract, look for:

• Whether "engine mounts" or "transmission mounts" are named
• Whether hydraulic or electronic mounts are included
• Any language excluding rubber parts or wear items

Your factory warranty may also cover mounts during the basic coverage period. Check your brand's terms on our makes page.

What to do next

• Pay attention to when the vibration or clunk happens
• Ask your mechanic to inspect the mounts at your next service
• Fix any oil leaks that could drip onto rubber mounts
• If you have a service contract, check coverage and get authorization before repairs. Our claims page explains the usual process.

How Warranty Wizards can help

We help you compare plans from third-party providers and explain what a plan covers before you buy, including parts like engine mounts that vary from plan to plan. You can get a free quote to see your options.