A typical rubber front mounting on a longitudinally mounted engine; one of a pair, clearly visible from above.
Check with the engine running. Pull the throttle linkage of the carburettor so that the engine speeds up for a moment.
As it does so, watch the mountings; as the engine suddenly rocks on the mountings, any cracks or unbonded areas should open up.
Repeat with the engine switched off by rocking the engine by hand on its mountings.
An engine that is mounted longitudinally usually has two front mountings, which are easy to see. It also has rear mountings at the gearbox.
A transverse engine may have three or four mountings, some of which have to be checked (and if necessary replaced) from under the car.
Raise the front wheels on ramps with the handbrake applied and the rear wheels chocked. Ask a helper to actuate the throttle.
If any mounting is faulty, replace both front ones for a longitudinally mounted engine, or all the mountings of a transverse one.
Replacing the mountings