DIY Polyurethane Motor Mounts - A Guide | Polyurethane Motor Mounts Diy

Revitalize Your Ride: The Ultimate Guide to Polyurethane Motor Mounts DIY

Ever felt like your engine's having a bit too much of a party under the hood? Or maybe you're chasing that crisp, responsive feel you get from high-performance cars? Chances are, your motor mounts might be telling a tale of wear and tear, or simply not up to the task of spirited driving. This is where polyurethane motor mounts DIY comes into play, offering a fantastic blend of durability, performance, and serious cost savings if you're willing to get your hands dirty.

Let's be real, tackling a project like this can feel a little daunting at first. But imagine the satisfaction of knowing you've significantly upgraded your car's feel and longevity with your own two hands. We're going to dive deep into why polyurethane is such a game-changer, whether this DIY project is right for you, and exactly how you can make it happen. So, grab a coffee, put on your thinking cap, and let's get into it!

Why Polyurethane? A Game-Changer for Your Mounts

Before we get into the nitty-gritty of the "how-to," let's talk about the "why." Most cars roll off the factory line with rubber motor mounts. And while rubber does a decent job of isolating engine vibrations, it's not exactly built for the long haul or high-performance demands. Over time, rubber degrades – it cracks, softens, and basically turns into a squishy mess thanks to heat, oil, and just plain old age. When that happens, your engine starts to move around more than it should, leading to:

Excessive engine movement: You might feel clunks when shifting, especially in a manual.
Reduced power transfer: Some of that engine's power is wasted jostling the engine itself instead of sending it directly to the wheels.
Vague handling: Especially if your transmission mount is also shot.
Potential damage: Excessive movement can stress other components like hoses and wiring.

Enter polyurethane. This synthetic polymer is like rubber's tougher, smarter cousin. It's far more resistant to chemicals, oils, and extreme temperatures. What does that mean for your motor mounts?

Superior Durability: Polyurethane mounts last significantly longer than rubber, often outliving the car itself.
Reduced Engine Movement: Its firmer nature dramatically reduces engine slop, leading to more direct power delivery and crisper shifts. You'll feel a much more "connected" driving experience.
Better Performance: Whether you're street driving or hitting the track, that stability translates into improved throttle response and a more predictable feel.
Cost-Effective DIY: Buying aftermarket polyurethane mounts can be pricey. Doing it yourself, often by filling existing rubber mounts, is incredibly budget-friendly.

Now, there's a trade-off, and it's important to be honest about it: Noise, Vibration, and Harshness (NVH). Because polyurethane is firmer, it transmits more engine vibration into the chassis and cabin. This can feel a bit more raw, a bit less refined. For some, it's part of the performance appeal; for others, it might be a deal-breaker on a daily driver. It's all about finding that sweet spot, which we'll discuss when talking about durometer.

Is Polyurethane Motor Mounts DIY Right for You?

So, you're intrigued. But should you be doing this? It's a fair question!

The Upsides of DIY

Massive Savings: This is often the biggest motivator. Aftermarket poly mounts can run you hundreds of dollars. The materials for a DIY fill project? Often less than fifty bucks.
Customization: You get to choose the durometer (hardness) of the polyurethane, tailoring the mount's firmness to your specific needs – from mildly stiffer street cars to track-focused machines.
Sense of Accomplishment: There's nothing quite like the pride of tackling a substantial car project yourself and then feeling the tangible results every time you drive.
Learning Experience: You'll gain valuable mechanical skills and a deeper understanding of your vehicle.

What to Consider

Time Commitment: This isn't a quick fix. You'll need time for prep, pouring, and especially curing (which can take 24-48 hours).
Basic Mechanical Skills: You'll need to be comfortable jacking up your car, supporting the engine, and removing/installing motor mounts. If you've never touched a wrench, this might be a steep learning curve.
Tools: While not extensive, you'll need some basic garage tools.
Patience: Polyurethane work requires patience, especially during the curing phase. Rushing it can lead to failure.
NVH Tolerance: Seriously, think about this. If you value a super quiet, vibration-free ride above all else, firmer polyurethane might not be your jam.

If you're reasonably handy, have access to a safe working space, and are prepared for a bit more "connectedness" in your ride, then a polyurethane motor mounts DIY project is absolutely within your reach.

The "How-To": Making Your Own Polyurethane Motor Mounts

Alright, let's get down to brass tacks. There are a couple of main approaches to DIY polyurethane mounts, but the most common and accessible is filling existing mounts.

1. Understanding and Removing Your Existing Mounts

First things first, you need to know what you're working with.

Locate them: Engine mounts are usually found on either side of the engine, attaching it to the chassis. Transmission mounts are typically under the transmission, connecting it to the subframe.
Inspect them: Look for cracks, tears, or excessive squishiness in the rubber. If the mount is completely separated, you'll likely need new outer sleeves or internal metal components.
Removal: This step varies greatly by car. You'll need to safely jack up and support your car, then use an engine hoist or a block of wood and a jack under the oil pan (with a buffer like another piece of wood) to support the engine. Remove the bolts holding the mount to the engine and the chassis. Take pictures as you go – they'll be invaluable for reassembly!

2. Choosing Your Polyurethane Durometer

This is arguably the most critical decision for your DIY poly mounts. Durometer is a measure of hardness. It's expressed as a number followed by an "A" (e.g., 70A, 85A). Higher numbers mean firmer material.

60A-70A (Softer): Great for daily drivers where you want increased durability and a bit more firmness without a significant increase in NVH. Think mild upgrade.
75A-85A (Medium): This is often the sweet spot for enthusiast street cars or occasional track use. You'll definitely notice the firmness and NVH increase, but it's generally manageable.
90A+ (Harder): These are typically for dedicated track cars or serious performance builds. NVH will be quite high, but engine movement will be minimal.

For most folks doing a polyurethane motor mounts DIY, a 70A or 80A durometer is a good starting point. You can buy specific pourable polyurethane kits online from brands like Energy Suspension, Powerflex, or generic industrial suppliers. They usually come as a two-part liquid (A and B) that you mix.

3. Preparing Your Mounts for Filling

This is where the magic happens!

Clean, Clean, Clean: This is absolutely crucial for proper adhesion. Scrape out any loose or torn rubber. Use a strong degreaser (brake cleaner works well) to remove all oil, grease, and dirt. Scrub it with a wire brush or sandpaper to roughen the surface where the polyurethane will bond. Make sure it's completely dry. Any contaminants will prevent the poly from adhering properly.
Create Your Mold: If your existing rubber mount has voids (open spaces within the mount), you'll be filling these. Use strong masking tape or modeling clay to create a dam or mold around the edges of the void, ensuring the polyurethane doesn't spill out. If you're completely replacing all the rubber, you'll need to burn or cut out the old rubber and create a new mold using the metal shells of the mount. This is more involved and usually requires a custom-fit mold. For a first-timer, filling voids is much easier.
Optional: Drill Holes: For mounts with very small voids or if you want to ensure the poly gets into every nook and cranny, you can carefully drill small holes into the rubber in strategic places.

4. Mixing and Pouring the Polyurethane

Follow the instructions on your specific polyurethane kit precisely.

Work in a Well-Ventilated Area: These chemicals can have strong fumes.
Wear Safety Gear: Gloves and eye protection are a must.
Accurate Mixing: Use separate measuring cups for components A and B, then combine them into a third, clean cup. Mix thoroughly but not too vigorously to avoid introducing excess air bubbles. Most kits have a specific mix ratio (e.g., 1:1 by volume or weight). Time is critical here – you'll usually have a "pot life" of just a few minutes before it starts to cure.
Pour Carefully: Slowly pour the mixed polyurethane into the voids of your prepared mounts. Work slowly to allow air bubbles to escape. Overfill slightly, then scrape off the excess with a plastic spreader or spatula.
Bubbles: If you see a lot of bubbles, a heat gun (on a very low setting, from a distance) can help bring them to the surface. A vacuum chamber would be ideal, but that's a bit much for a DIY project!

5. Curing Time

This is where patience truly comes in.

Hands Off! Let the mounts cure completely. This typically takes 24-48 hours, depending on the specific product, temperature, and humidity. Don't rush it. Curing too fast or disturbing it can weaken the final product.
Optimal Conditions: Most polyurethanes cure best at room temperature, ideally between 65-80°F (18-27°C).

Tools and Materials You'll Need

Safety Gear: Gloves, eye protection.
Basic Socket/Wrench Set: For removing and installing mounts.
Jack & Jack Stands: Absolutely essential for safe vehicle lifting and support.
Engine Support: Engine hoist, or a floor jack with a wood block/2x4 to support the oil pan.
Degreaser/Brake Cleaner: Lots of it!
Wire Brush/Sandpaper: For surface prep.
Polyurethane Kit: The specific durometer you choose.
Mixing Cups & Stir Sticks: Disposable ones are best.
Masking Tape/Modeling Clay: For creating molds.
Razor Blade/Exacto Knife: For trimming excess cured poly.
Torque Wrench: Crucial for tightening bolts to spec during reinstallation.

Installation and Post-DIY Expectations

Once your DIY polyurethane mounts are fully cured, it's time for reinstallation!

Reverse the Removal Process: Refer to those photos you took earlier. Ensure all bolts are started by hand to prevent cross-threading.
Torque Specs: Use your torque wrench to tighten all bolts to your car's factory specifications. This is vital for safety and mount longevity.
First Drive: Expect a difference immediately. You'll likely feel more engine vibration, especially at idle. However, you should also notice a much firmer, more direct feel when accelerating, braking, and shifting. This "new" NVH can sometimes lessen slightly over the first few hundred miles as everything settles.
Check Bolts: After about 50-100 miles, it's a good idea to recheck the torque on all the mount bolts, just in case anything has settled.

Troubleshooting Common Issues

Excessive NVH: If it's truly unbearable, you might have chosen too high a durometer. Unfortunately, the fix here is to either live with it or replace the mounts with softer ones (or go back to rubber).
Polyurethane Not Curing/Sticky: This usually points to improper mixing ratio, insufficient mixing, or incorrect ambient temperature.
Cracks in Polyurethane: Could be due to improper mixing, inadequate prep (poor adhesion), or extreme stress if the mount design wasn't ideal for a full poly fill.

Final Thoughts: Drive With Confidence!

Undertaking a polyurethane motor mounts DIY project is a rewarding experience. It gives you incredible insight into your vehicle's mechanics, saves you a significant chunk of change, and results in a tangible, performance-enhancing upgrade. Yes, it takes time and effort, but the feeling of a more responsive, connected, and durable ride that you built? That's priceless.

So, if your current mounts are feeling a bit tired, or you're just itching for a project that genuinely improves your driving experience, don't be shy. Dive in, take your time, and enjoy the transformation. Your car (and your wallet) will thank you!