Modern engines are complicated. There are so many moving pieces, precision engineering, and advanced machining that go into building one. However, making a good engine isn’t the end of the journey for automotive engineers. Now they need to figure out how to bolt it onto a car properly. This is where engine mounts come in. Our goal today is to tell you everything you need to know about this particular car component. We’ll discuss engine mount replacement procedures, symptoms of failed engine mounts, and more.
The Function of an Engine Mount
Engine mounts are simple and often small components tasked with a massive job. Bolting an engine onto a car is much more complicated than it looks on paper. As it turns out, your average engine is like a wild buck. It wants to jump, twist, and turn when you apply the gas.
What if we take a bunch of brackets and bolt that sucker down? Problem solved, right? Not really. Bolting the engine down using simple brackets and bolts would secure it in place, but it would cause another rather massive problem — vibrations.
Your average engine is rather violent while it works. It’s a vibration and noise powerhouse. The moment you secure it to the rest of the car using metal to metal contact, you’ll end up with all of those violent vibrations inside the passenger cabin. Depending on the car you drive and the engine that comes with it, you might be in for a rough ride.
Enter engine mounts. Although engine mounts come in all kinds of different flavors, they all share the same principle — adding a buffer between the engine and the body/chassis of the car.
Different Types of Engine Mounts
Over the past few decades, there have been all kinds of different motor mounts used in various cars. That being said, we can recognize three main types – solid mounts, hydro mounts, and electronic mounts.
Solid mounts are the most common type of mount but also the simplest one of the bunch. Your average solid mount features a piece of rubber or other materials laminated between two pieces of metal.
The rubber or a composite (usually polyurethane) that sits between the metal brackets can be of varying stiffness. Some mounts are stiffer than others, but overall, they do a great job soaking up vibrations. This is also the same type of design you’d find on many transmission mounts. Its popularity can be attributed to the fact that It’s simple and that it works.
The only issue with standard rubber mounts is the fact that they tend to become brittle over time. Once that happens, you’re looking at potentially cracked rubber and possible mount failure.
Since standard solid rubber mounts weren’t cutting for more sophisticated cars, various manufacturers came up with hydraulic mounts. These are filled with fluid, which is used to soak up any vibrations coming from the engine. Since fluid doesn’t compress but is still fairly soft, you’re getting good damping properties as well as the necessary stiffness when things get out of hand.
However, hydro mounts have a built-in flaw — their sealed enclosure tends to fail after years of use and abuse. Once a hydro mount leaks, it’s game over. Always use Genuine or OEM hydro mounts on your car.
Electronic mounts are the latest evolution of this component. At some point, it became possible, and more importantly, feasible, to use active electronic vibration dampening. An average electronic mount uses active components to counteract the vibration of the engine. Some are running various vacuum systems, while others use different means of active dampening to kill those vibrations in real-time.
That being said, electronic mounts aren’t there because an engineer somewhere had decided to see just how far they could push this tech. Active motor mounts have a very real application in vehicles that feature electronic cylinder shutoff systems. The vibration and noise profile of such engines is continually changing, which requires an active vibration negation system.
Symptoms of a Failed Engine Mount
Now that we know a bit about motor mounts let’s talk about diagnosing a bad mount. Here are the most common symptoms you’ll run into if any of your mounts start acting up.
One of the most apparent symptoms of a bad mount is an increase in vibrations. As the mount fails, it will also lose its ability to soak up noise and vibrations.
That being said, hydro mounts will usually be worse off than regular rubber mounts. Rubber mounts tend to show a few more symptoms in combination with the increase of vibration.
Motor Moving Around
Although we’ve focused mainly on the vibration and noise dampening properties of motor mounts, they also have another important function — holding the motor in place. When engine mounts fail, they are no longer capable of locking the motor firmly in place.
At that point, you’ll see and often feel the engine moving around excessively. All you really need to do is have someone apply gas while the gearbox is in neutral with you looking at the engine. You will see it visibly torque.
Clunking Noises and Impacts Felt in the Cabin
If you ignore a bad mount long enough, there is a good chance it will ultimately lose whatever dampening medium it uses. As a result, the engine will create clunking noise and send impact vibrations through the body of the car. It would be best if you considered this symptom as a final warning to take action.
How to Replace a Motor Mount?
The motor mount replacement is usually a simple enough job. We say ‘usually’ because all cars are different in this regard. Some will make your life living hell when you try to change the mount. Either way, here are the universal steps that will work on most cars.
Step 1 – Jack the Engine
The first thing you’ll want to do is jack up the engine using a floor jack. Make sure to put a block of wood between the jack and your oil pan. Don’t put too much tension on your engine mounts, as that will make removing them much harder. Also, it goes without saying that your car should be on flat ground and secured before you start doing anything.
Step 2 – Remove the Engine-Side Bolts
With the engine supported, locate the motor mount you want to remove and undo the bolts that connect the mount to the engine. These are usually accessible from the top and might require the use of extension pieces.
Step 3 – Remove the Bottom Mounts
Next, get under the car and remove the bolts that hold connect the motor mount to the body of the car. You’ll most likely have to get under the car to reach these.
Step 4 – Lift the Engine Slightly
With the mount lose, jack the engine just enough where you can wiggle out the old mount. Some mounts come with a heat shield, so make sure to transfer it to your new mount before tossing the old one in the trash.
Step 5 – Install the New Mount
Next, install the new mount where the old used to be while ensuring it is oriented the right way. Engine mounts usually have orientation indents in them, which should prevent you from installing them the wrong way around.
Once you install the mount, thread in the bolts that connect the mount to the frame before lowering the engine.
Step 6 – Lower the Engine
Slowly lower the engine until the mount fully suspends it. With the new motor mount in place, go ahead and tighten the bolts following correct torque specs if you have them. If not, just tighten everything down by feel.
How to Make Your Engine Mounts Last Longer?
There are a few things you can do (or not do) that will prolong your motor mount’s lifespan. These tips also extend the life of your transmission mounts. For one, try not to spill any liquids over your rubber mounts. Chemicals such as brake fluid, power steering fluid, and similar will degrade the rubber or polyurethane materials in the mount.
More importantly, try not to gun your car too much. Launching a car is fun, but it puts a serious amount of stress on your engine mounts.
Always Use Quality Engine Mounts
We always recommend using only OEM or Genuine engine mounts on your car. Check out our online store to find out which mounts from our catalog fit your car’s make and model. Feel free to get in touch with our customer support if you have any questions regarding our offer!