To check motor mounts, inspect each mount with a flashlight for cracks, sagging and leaks, then have a helper hold the brakes firmly and gently apply throttle in drive and reverse while you watch the engine from the side. A healthy engine barely moves, while a bad motor mount lets the engine lift, lurch or clunk. 

You do not need special equipment to find out whether your engine mounts are worn. A flashlight, a pry bar and a careful helper will tell you most of what you need to know in a few minutes. Here is how to check motor mounts and how to check engine mounts and torque struts safely, how to tell if motor mounts are bad, and what to do next with our polyurethane engine mount bushings.

Safety First Before You Check Engine Mounts 

The torque test involves the engine running in gear, so set up carefully. Park on level ground with plenty of clear space in front and behind, chock the wheels and make sure your helper is comfortable holding the brake pedal firmly. Stand to the side of the engine bay, never in front of or behind the vehicle, and keep hands, hair and loose clothing well away from belts and fans. 

Use only short, gentle throttle applications during the test. The aim is to load the mounts, not to launch the vehicle, and a few seconds of light throttle is enough to reveal a problem.

Step 1: Inspect the Motor Mounts Visually 

With the engine off and cool, open the hood and locate each mount. You may need to look from underneath for the transmission mount and lower torque mounts. Shine a flashlight on the cushion between the metal brackets and look for:

  • A cracked motor mount: Deep cracks or tears running through the rubber cushion.
  • Separation: Rubber pulling away from the metal bracket it is bonded to.
  • Sagging or collapse: The mount looking squashed or the engine sitting tilted.
  • Fluid leaks: Oily residue around hydraulic mounts where fluid has escaped.
  • Rub marks: Signs the engine has hit hoses, wiring, the fan shroud or exhaust. 

Oil-soaked rubber is worth noting even if it looks intact, because oil softens rubber and leads to early failure. 

Step 2: Do the Brake Torque Test 

Start the engine and have your helper hold the brake firmly. With the vehicle in drive, ask them to apply light throttle for a second or two while you watch the engine from the side. Repeat in reverse, since the engine twists the opposite way. 

A healthy engine shifts only slightly and settles immediately. If the engine lifts noticeably at one side, lurches, or you hear a clunk as the throttle is applied or released, that mount is worn. The side that lifts is usually the mount that has failed. 

Step 3: Use a Pry Bar With the Engine Off 

Switch the engine off and remove the key. Place a pry bar carefully between the engine bracket and the frame mount near each cushion, then apply gentle pressure. A good mount resists with only a little give, while a worn mount lets the bracket move easily or shows a gap opening in the rubber. 

Repeat the same check on the transmission mount from underneath. Transmission mounts wear too and can cause similar clunks when shifting. 

Motor Mount Tests at a Glance

Test 

Good mount 

Bad motor mount 

Visual inspection 

Solid rubber, no cracks or leaks 

Cracks, tears, sagging or oily residue 

Brake torque test in drive and reverse 

Slight movement that settles immediately 

Engine lifts, lurches or clunks 

Pry bar test 

Firm with little give 

Bracket moves easily or rubber gaps open 

Engine position

Sits level in the bay 

Tilted or lower on one side 
 

Rule Out Other Causes of Vibration

Engine vibration does not always mean bad mounts. A misfiring cylinder, worn spark plugs, unbalanced wheels or a damaged driveshaft can all cause similar shakes. If the mounts pass every test but the vibration remains, have the ignition and fuel systems checked before replacing parts. 

If the mounts are worn, our list of bad motor mount symptoms helps confirm what you found, and our guide to motor mount replacement cost helps you plan the repair.

Motor Mount Inserts - 4 Mount SetMotor Mount Inserts - 4 Mount Set

Motor Mount Inserts - 4 Mount Set

Replacing Worn Mounts With Polyurethane

Our range includes polyurethane insert kits that fit into the existing mount shell, front and rear motor mount inserts, torque strut bushings and complete engine and transmission mount sets. Insert kits install in under an hour on applicable platforms, and complete sets take up to about two hours. Polyurethane resists heat, oil and torque reaction far better than rubber, and warranties range from 3 years to limited lifetime depending on the product. 
Motor Mount Set - Small Block V8 OnlyMotor Mount Set - Small Block V8 Only

Motor Mount Set - Small Block V8 Only

FAQs

Looking for more information about checking motor mounts? Below we answer the most commonly asked questions

How do you tell if motor mounts are bad?

Look for cracks, sagging and leaks, then watch the engine while a helper applies light throttle in gear with the brakes held. Excessive lifting, lurching or clunking means a mount is worn.

How do you check engine mounts without a lift?

Most checks can be done from above with the hood open and a flashlight. The brake torque test also works with the vehicle on the ground, though the transmission mount is easier to see from underneath.

How much should an engine move on its mounts?

An engine on good mounts shifts only slightly under load and settles immediately. Large lifts at one side, lurches or clunks point to a worn mount.

Is the brake torque test safe?

It is safe when done carefully with light throttle, a helper holding the brake firmly and everyone standing to the side. Keep everyone well clear of belts and fans throughout.

Can a cracked motor mount still work?

Fine surface cracking may not be a failure yet, but deep cracks or rubber separating from the bracket mean the mount is losing its strength. Plan to replace it before it fails completely.

Should I check the transmission mount too?

Yes, transmission mounts wear like engine mounts and can cause clunks when shifting. Check it from underneath with a flashlight and pry bar.

If you found a worn mount, fix it with parts built for torque and heat. Browse our engine mount bushings for your engine and drivetrain.