Lexus LS460 & LS600h Engine Mount Failure: Diagnosing Vibration and High Repair Costs (2007-2017)
This guide details the common symptoms of failed engine mounts on the 2007-2017 Lexus LS460 and 2016 LS600h, focusing on the critical differences between RWD and AWD parts.
- The most critical factor is drivetrain: engine mounts for Rear-Wheel Drive (RWD) and All-Wheel Drive (AWD) models are different and not interchangeable.
- Replacement is extremely labor-intensive and expensive, often costing over $2,000, with the majority of the cost being shop labor.
- The most common symptom of failure is a strong vibration felt in the cabin at idle, especially when in gear.
- When buying a used mount, check for fluid leaks, cracks in the rubber, and signs of collapse to ensure you are getting a good part.
RWD vs. AWD: A Critical Distinction
Before diagnosing any issues, it's crucial to understand that the engine mounts and brackets are different for Rear-Wheel Drive (RWD) and All-Wheel Drive (AWD) models. The 2016 Lexus LS600h was only sold as AWD, but the 2007-2017 Lexus LS460 was available in both configurations. Installing the wrong part will not work. Always verify your vehicle's drivetrain before ordering.
Warning: The most common mistake is ordering parts for the wrong drivetrain. The front engine mounts (insulators) and the mounting brackets are different between RWD and AWD models.
| Drivetrain | Part Type | Common Part Numbers | Notes |
|---|---|---|---|
| RWD | Front Mount (Insulator) | 12361-38220, 12361-38221 | Fits left and right sides. Part number 12361-38221 is an updated version that replaces 12361-38220. |
| AWD | Front Mount (Insulator) | 12361-38210, 12361-38281 | Specific to AWD models. |
| AWD | Left (Driver) Bracket | 12315-38050, 12302-38170 | Mounting bracket for the driver's side on AWD models. |
| AWD | Right (Passenger) Bracket | 12311-38060 | Mounting bracket for the passenger's side on AWD models. |
Symptoms of a Failed Engine Mount
When an engine mount fails, the connection between the engine and the chassis is compromised. This typically results in one or more of the following symptoms:
- Excessive Vibration: This is the most common complaint. You may feel a deep vibration through the steering wheel, pedals, or the entire cabin, especially when the car is idling in gear (Drive or Reverse). The vibration may lessen when the car is in Park or Neutral.
- Impact Noises: A loud "clunk," "thump," or "bang" when you shift gears, accelerate, or decelerate is a strong indicator of a bad mount. This sound is the engine physically shifting and hitting its limits due to the failed mount.
- Engine Movement: A healthy engine should have very little movement. With a failed mount, the engine may visibly lurch or rock in the engine bay when shifting from Park to Drive or when an assistant briefly revs the engine. 🎬 Watch: See how much a failed mount allows engine movement.
- Rough Sensation: The car may feel generally rough, and gear shifts might feel harsher than usual, even if the transmission is healthy.
Known Issues, TSBs, and Recalls
There are no specific recalls or widespread Technical Service Bulletins (TSBs) from Lexus for premature engine mount failure on the LS460 or LS600h. Failure is typically due to age, mileage, and wear on the hydraulic rubber components.
Misdiagnosing Vibration: Brake-Related TSB
It's important not to confuse engine mount vibration with other issues. Lexus issued TSB No. SB0036-15 for some 2007-2015 LS460 models that could exhibit a vibration or pulsation in the steering wheel or brake pedal when braking at highway speeds. This issue is caused by the brake calipers and rotors, not the engine mounts. If your vibration only occurs during braking, investigate your brakes first.
Replacement Difficulty & Cost Breakdown
Replacing the front engine mounts on a Lexus LS460 or LS600h is a difficult and labor-intensive job, not recommended for the average DIY mechanic. The official Lexus repair manual procedure can even involve dropping the entire front subframe with the engine and transmission.
Experienced mechanics have found shortcuts, such as supporting the engine, unbolting the mounts, and carefully lowering or prying the subframe to gain enough clearance. 🎬 See this mechanic's shortcut for a faster mount replacement. Even with these methods, the job is complex and requires significant time and specialized tools. This difficulty is reflected in the high labor costs.
Pro Tip: Due to the extremely high labor cost for this repair, opting for a quality used OEM engine mount can provide significant savings while retaining the original factory quality and ride characteristics, which are often superior to cheaper aftermarket alternatives.
| Item | Estimated Cost | Notes |
|---|---|---|
| New OEM Mounts (Parts) | $350 - $500 (for a pair) | Prices range from about $170 to $250 per mount. |
| New Aftermarket Mounts (Parts) | $150 - $250 (for a pair) | Can be a cheaper alternative, but may not offer the same damping and longevity as OEM. |
| Used OEM Mounts (Parts) | $75 - $200 (for a pair) | Offers OEM quality at a significant discount. Inspection is key. |
| Shop Labor | $1,500 - $2,300 | Labor is the largest part of the expense, estimated at 9-13 hours. |
| Total Professional Replacement | $1,778 - $2,502+ | This is the estimated range for a professional shop to replace the mounts using new parts. |
Buying a Used Engine Mount: What to Check
Given the high cost of new parts and labor, a low-mileage used OEM engine mount is an excellent value. However, you must inspect it carefully before purchase.
- Verify Part Number: First and foremost, ensure the part number matches your vehicle's drivetrain (RWD or AWD). Cross-reference the number stamped on the part with the tables in this guide.
- Inspect the Rubber: Look for any cracks, tears, or signs of dry rot in the black rubber body. The rubber should be pliable, not hard and brittle.
- Check for Leaks: These are hydraulic mounts, meaning they are filled with fluid. Look for any dark, oily residue on the mount's surface. A leaking mount has failed and should not be purchased.
- Check for Collapse: Compare the used mount to photos of a new one. If the mount looks compressed or "squashed," it has likely collapsed and lost its ability to absorb vibration. The metal components should not be touching or be unusually close to each other.
- Examine Mounting Points: Ensure all threaded holes and mounting surfaces are clean and undamaged.
Can I drive with a bad engine mount?
You can, but it's not recommended for long. While the engine is unlikely to fall out, the excessive movement can strain and damage other components like coolant hoses, wiring harnesses, exhaust pipes, and transmission linkages. Addressing the issue promptly is the safest and most cost-effective approach.
Why is the replacement so expensive?
The cost is almost entirely due to labor. The engine mounts are located in a very tight space between the engine and the front subframe. To access them, a mechanic must either partially drop the subframe or lift the engine, both of which are time-consuming procedures.
How do I know if my LS460 is RWD or AWD?
The easiest way to tell is to look for an "AWD" badge on the trunk lid. If there is no badge, it is likely a Rear-Wheel Drive model. You can also have a dealership run your Vehicle Identification Number (VIN) to confirm the vehicle's original specifications.
Could my vibration be something other than an engine mount?
Yes. Vibration can also be caused by worn tires, unbalanced wheels, driveshaft issues, or brake problems. However, if the vibration is most noticeable at idle and changes when you shift gears, engine mounts are a primary suspect. 🎬 Watch: A guide on how to diagnose bad motor mounts. If the vibration only happens when braking from speed, check for brake issues as noted in TSB SB0036-15.
Helpful Videos
Technical Specifications
OEM Part Numbers: 12361-38221 (RWD Mount) 12361-38220 (RWD Mount, superseded) 12361-38210 (AWD Mount) 12361-38281 (AWD Mount) 12315-38050 (AWD Left Bracket) 12311-38060 (AWD Right Bracket) 12302-38170 (AWD Left Bracket)
These are hydraulic fluid-filled rubber engine mounts.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Lexus LS460:
- Lexus LS600h: