If your car has over 100,000 miles on it and you’ve never touched the engine or transmission mounts, you should seriously consider changing them. These unique pieces of hardware live hard lives and contribute to your car’s comfort and responsiveness quite a bit. You might not necessarily need “high-performance” ones, even if you do track days or spirited driving, but fresh mounts alone can sometimes bring real spryness back to an older car.
I’ve had mounts changed in a few different cars now. I’ve tried OEM ones, knockoff brand factory-style ones, and a few different aftermarket performance picks. Your mileage and experience may vary, but if you’re thinking about replacing mounts, or you just read my intro and are now curious about these interesting little auto parts, I can shed some light on what to expect from various options.
Performance-Upgrade Mounts With Minimal Vibration Penalty
There are ways to do a slightly more aggressive driveline mounting setup than stock without dramatically worsening your car’s noise, vibration, and harshness too much. After a lot of research, I landed on these two sets in particular that really impressed me, and inspired me to make this diary entry.
The 034Motorsport “Street Density” Mounts in My BMW
My 2003 BMW 330ci is bone stock with nice tires, used by my wife and me for backroad blasts and the occasional road trip. Comfort is the priority, but I do love the E46’s undertones of sportiness.
A little difficulty engaging reverse inspired me to start looking into transmission mounts, among other things. With the car jacked up, they looked intact but a little crusty. The engine mounts had some alligator-skin texture to them too. At 160,000 miles, I was confident that replacing them would pay off. My first instinct was to grab some OEM replacements, but a salesperson at FCP Euro turned me on to a kit from 034Motorsport. They promised me these would add a little more sharpness to the car’s personality than factory ones without the intense vibrations normally associated with performance mounts. Here’s the rundown from the side of the box:
“034Motorsport Street Density engine mounts and transmission mounts are manufactured from 55 durometer rubber, which is a significant upgrade from the rubber used in-stock BMW mounts. Since the mounts are also void-free and solid-filled, the resulting mount is substantially stiffer than stock, without introducing any additional noise, vibration, or harshness into the cabin. The mount bodies are made from high-quality steel using OEM production techniques.”
Rubber hardness is usually expressed as a two-digit number, and 55 is on the low (soft) side of performance mounts.
I ordered this kit, had it installed by my go-to local wrenchman, and boy, was I delighted with the results. The car feels smoother and sharper, but it’s still every bit as comfortable as ever. I hadn’t heard of this company at all (apparently it usually specializes in VW and Audi parts) but a few thousand miles on its Street Density engine and transmission mounts and I’m loving them—strongly recommend.
I’m not trying to claim that it transformed the entire driving experience, but it really did elevate the driving experience everywhere from casual drives to the store to hard-charging around the mountains. The car simply feels tighter, especially coming on and off the throttle, and in gear changes.
The Hasport 62A “Partial Kit” in My Honda
About a year ago, my friend and former colleague Chris Rosales was test-driving my tuned Civic and mentioned I should check out its rear mount (which kind of holds both the engine and transmission). Indeed, when I got off the gas, there was a little more disruption than there should have been. Unlike my Bimmer, which I am committed to keeping in Bavarian businessman spec, my hard-partying Honda lives to be driven aggressively.
I was all set to order an ultra-stiff set of engine mounts, but research scared me off. Just about everyone I conferred with convinced me that’d make the car miserable to ride in. How much stiffness could a 200-horsepower Honda really need, anyway?
I ended up ordering mounts from Hasport, one of the best-known Honda engine mount outfits that’s been around forever. I got the softest (62 durometer) option for only the upper and lower mounting locations.
Hasport does sell a full mount kit for the eighth-gen Civic Si, but it also sells the upper and lower pieces alone, made to work in conjunction with the stock mounts elsewhere. This, I was hoping, would provide a little more response without making the car unbearably rough. Also, it was cheaper than a whole mount kit.
To my surprise, even with just the rear mount installed and all the other ones stock, the car gained what I consider pretty serious rumble at idle. The whole auditory experience inside the car changed dramatically. The engine tone sounded deeper, the start-up was more ominous. Of course, it wasn’t the engine sound itself that changed. The whole harmonic experience had been altered by replacing a spent rubber mount with a (relatively) hard one.
That said, the car’s responsiveness—especially coming off throttle—did improve in a meaningful way. Interestingly, when I installed the Hasport upper mount, I didn’t really feel any change—that lower one must be doing more work. Soon, I’ll replace the others with fresh factory ones and I’m optimistic that I’ll get another improvement.
Meanwhile, I’ve gotten used to the Civic’s new noisiness. But it did make me appreciate the fact that performance motor mounts are not for everyone.
How Do I Know When I Need New Engine Mounts?
Motor mounts usually degrade slowly. Ever hear that adage about “if you drop a frog in boiling water he’ll jump out but if you put him in lukewarm water and heat it, he won’t notice the temperature rising?” That’s kind of how it is with engine mounts—you might not really notice that they’re weakening until it gets really bad and the mounts are completely disintegrated. Also, that frog thing is kind of a gross saying, I’m just now realizing. Leave those frogs alone!
If the car kind of jerks a little as you get on or off the gas, that might be an indicator that a mount is messed up. You can visually inspect an engine mount too—look for cracks or fluid leaks (many use fluid for shock absorption)—but you might not see tiny defects.
All else being equal, I would say about a decade of continuous use or weather exposure might be a good time to preemptively replace your mounts if they’ve never been done.
Should I Get High-Performance Engine Mounts or Stock Ones?
If you’re not sure, my suggestion is to get stock ones. I have two main reasons for this. First: Aftermarket motor mounts add more vibration than the average non-gearhead is probably expecting. Like I said earlier—just a low-harshness (62A) high-quality (U.S.-made Hasport brand) mount set on my 200 horsepower Honda added considerable rumble at idle. It’s not too bad while underway, but if you spend a lot of time in your car, make sure you really are OK with a lot more shake and rattle to your roll before getting stiffer-than-stock engine mounts.
Look around to see what your options are for your car. Whatever you do end up going with, I’d recommend replacing mounts as a set for the sake of symmetry.
Secondly, and some might consider this the more important point: If the idea of “increased responsiveness” is drawing you to go with aftermarket mounts, good news! Fresh OEM-style ones will absolutely make your car feel more responsive than your old cracked ones.
If you’re setting your car up in a specific way or you just like to feel hardcore, by all means, throw in some stiff-ass engine mounts and have fun pretending you’re in a shifter cart. For those of you who are into driving but don’t want your teeth rattled out when you engage air conditioning, the middle-ground performance engine mount upgrades like what I’ve done with my cars are well worth looking at. But if you’re on the fence or just looking for a mild upgrade, fresh factory-style mounts are the move.
Is It Hard To Change Engine Mounts?
Check out our engine-mount replacement guide if you’re looking for DIY tips. The difficulty in an engine mount job depends entirely on the car, and even the mount itself. Some are super easy to access, while others are buried under labyrinths of coolant plumbing or exhaust piping. Access, and what kind of climate you’ve been driving in, will be the main determining factors in how much pain you’re in for here. If a mount is really rusty and tough to reach, don’t let your kids help unless you’re ready to teach them all your swear words. There’s no shame in calling a pro—I did, on several cars, for this job.
But this FCP Euro video didn’t make the job seem too intimidating.
Most cars have similar links holding up the transmission, and on rear-drive cars, the differential will have some too. If you decide to tackle this yourself, make sure you double-check forums or repair guides to see if there’s an optimal order or a certain place you need to put a supporting jack on whatever vehicle you happen to be working on.
Conceptually, it’s quite simple—just secure the engine, remove bolts, remove mount, install new mount, install new bolts. Ah, if only all wrenching projects were as clean and easy as they look on paper!