Toyota 4Runner: Bad Motor Mount → Symptoms + Diagnosis

While your Toyota 4Runner’s engine mounts can last the life of the entire vehicle, it is possible that they will go bad.  Vibration and a clunking sound are the two most noticeable symptoms when driving the vehicle.  There are plenty of visible signs as well.

Engine mounts connect the engine to the frame of the 4Runner.  They also provide vibration dampening.  It is essential to the operation of the vehicle that they are working properly.  If you have bad motor mounts, it’s usually pretty obvious.

 

 

Bad Engine Mount Symptoms:  Toyota 4Runner

The job of the motor mounts is to keep your 4Runner from rattling to death, while keeping the engine in the engine bay. All of the symptoms of a bad motor mount are going to be related to vibration, and the motor moving from it’s proper location. That being said, here are the three most common symptoms of a bad motor mount.  They usually happen in stages.

 

Stage 1: Vibrations

The most noticeable symptom of a motor mount that is going bad is vibration. That is, more vibration than you would typically feel when you are driving your 4Runner.  You’ll know when it’s happening.  It may not necessarily feel like the vehicle is going to rattle apart, but it’s very noticeable. 

This is the most prominent symptom of a bad engine mount, and the first one that you’ll typically notice. If it is left alone long enough, it’ll lead to hard clunking sounds, which we’ll cover next ↓.

Stage 2: Clunking

An engine mount that has gone bad will begin to exhibit a clunking sound. This sound will be most noticeable when putting your 4Runner in and out of gear, when the engine shifts, as well as when you accelerate or de-accelerate abruptly.

This clunking comes from the mount being worn and having enough play to move when the force suddenly changes. This clunking may be accompanied by, or lead to full on engine movement ↓.

Stage 3: Engine Movement

If you are driving and you feel the engine banging around, that’s a sure indication that a motor mount has failed.  Really, you shouldn’t drive a vehicle with a motor mount clunking or even vibrating.  If you hear and feel the engine rolling around, it’s time to stop driving and have the motor mounts replaced immediately.  It’s going to cause all sorts of collateral damage in there.

 

Bad Motor Mount Diagnosis:  Toyota 4Runner

You can inspect the motor mounts and look to see if they have any free play.  If you take a look at your 4Runner’s engine as it goes in and out of gear, it is normal to observe some movement of the engine as it torques one way or the other.  It is not normal for it to make a clunking noise, or move excessively.  It is very difficult to tell that a motor mount is bad just by looking at it. That’s why it’s better to look for the signs of a bad motor mount, than to look at the mounts themselves.

Here are some ways of telling if your engine mount is bad just by looking for signs.

Drooping

One of the best ways that you can tell that you have a bad motor mount is if it is drooping to one side.  An engine is meant to be level.  If it is tipping in any one direction, that is a very strong indication that you have a bad motor mount.

Exhaust Leak

As your engine moves around the engine bay, it can cause an exhaust leak.  Exhaust leaks are pretty easy to distinguish.  A pinging or knocking sound coming from the exhaust is typical.  This happens because there’s not a lot of free play in the exhaust, so when it’s stressed, it’ll crack or blow a gasket.

Broken Hoses or Belts

There isn’t a lot of extra room in the modern engine compartment, which means that things can easily get cut or broken when they move.  This is exactly what can happen to hoses and belts when a motor mount fails.  A broken radiator hose can quickly cause a lot of damage if it runs your 4Runner out of coolant.

Related:  Toyota 4Runner Bad Serpentine Belt

Obvious Engine Damage

If you see their engine is damaged, and that there’s some corresponding damage on the frame, that is a telltale sign that you have a bad motor mount.

 

Why an Engine Mount Goes Bad

There are many reasons why your Toyota 4Runner could end up with a bad motor mount.  Here are the most common ones:

 

Collision Damage

One of the most common reasons that a motor mount will fail is when it gets damaged in an accident. Even if it’s a minor fender bender, that will often be enough to cause some serious damage to the mount.  That’s why even if you are in an accident and it’s not that bad, it’s always a good idea to take it into an alignment shop.  You should really take it to a mechanic and have them take a look and make sure there’s nothing else wrong.

 

Time/mileage

If you put enough mileage on a vehicle everything will eventually break. The motor mounts are no exception to that. This is particularly true because most motor mounts have rubber bushings. They will dry and crack as they age even without mileage being put on the vehicle. Some motor mounts are liquid filled. This provides great vibration dampening, but when they go bad they do it in a hurry. You can usually tell when one has gone bad, because they will be leaking fluid onto the frame. It’ll look like your engine mounts have an oil leak.

 

Poor Quality Mount

If your car has recently been in an accident, the motor mounts may have been replaced. But, that doesn’t mean that they were replaced properly. That’s why it’s important to find a good shop whenever you have a major repair done.

 

How Long Should Motor Mounts Last?

There’s no perfect answer to this question. It’s going to depend a lot on how often you drive, whether or not the vehicle’s ever been in a collision, and what the motor mount is made out of.  The best thing that you can do is have them looked at whenever you’re getting your vehicle serviced. Although, you should reasonably expect it to last for at least seven years.

 

Conclusion: 4Runner Bad Engine Mount Symptoms

Good luck finding out what’s going on with your Toyota 4Runner. Just remember while bad motor mounts are common, there can be other causes that would make your vehicle vibrate. It can be something as simple as a misfiring engine.  Although, you should get some sort of trouble code if that were the case.