Parts for your 2004 Toyota Highlander-Engine mount

2004 Toyota Highlander engine mount — what it does and when to replace it

Engine mounts are absolutely used on the 2004 Toyota Highlander. Factory sources including the Toyota Highlander 2004 Repair Manual (Engine Mechanical – Engine Mounting), the Toyota Electronic Parts Catalog for ACU20/25 (2.4L) and MCU23/28 (V6), and mainstream workshop manuals for Highlander/RX (1999–2006) list multiple mounts: a right-hand engine mounting insulator, a left-hand transaxle mount, plus front and rear mounts/torque rods. These support the engine and transaxle and manage vibration and torque under load.

For this model, the mounts do two big jobs: hold the drivetrain in the correct position under the bonnet, and isolate vibration so the cabin stays quiet and comfy. They’re a mix of rubber (and on some variants, hydraulic) insulators tuned to tame the 2.4L 2AZ-FE or 3.3L 3MZ-FE’s movement during take-off, gear changes, and over rough roads. When they’re healthy, they keep everything aligned so hoses, exhaust, and driveshafts aren’t stressed.

Over time, heat, oil contamination, and Kiwi/Oz road conditions can crack or soften the rubber. Tell-tale signs on a 2004 Highlander include:

• Noticeable vibration at idle in Drive, which eases in Neutral
• Clunks or a thud on take-off or when shifting
• Excessive engine rock when blipping the throttle
• Visible perishing or fluid weeping from a hydraulic mount

There’s no fixed kilometre interval, but many owners see mounts tired between 100,000–160,000 km. Inspection during routine servicing is smart: look for cracked rubbers, collapsed mounts, and loose or corroded hardware. If one has failed badly, it’s worth checking the others, as the extra load can accelerate wear.

Replacement is straightforward for a competent home mechanic, but it’s not a rush job. Support the engine/transaxle safely with a jack and a timber block, swap one mount at a time, and loosely fit all fasteners before final tightening. Final torque should be done at normal ride height to avoid pre-loading the rubber. Always follow the torque specs and sequences in the Toyota repair manual for the exact variant (FWD/AWD, 2.4L/V6), and replace any single-use stretch bolts if specified. After fitting, recheck clearances around the exhaust, radiator hoses, and driveshafts, then road test for NVH and any driveline clunks.

Quality OEM or reputable aftermarket mounts generally restore that smooth Highlander feel. Keeping oil leaks in check will also help new mounts last longer.

Popular questions about 2004 Toyota Highlander engine mounts

How many engine mounts does a 2004 Highlander have?
Most 2004 Highlanders use four primary mounts: right-hand engine mount, left-hand transaxle mount, plus front and rear torque mounts. Exact shapes and brackets vary by engine (2.4L vs V6) and whether it’s FWD or AWD, but the layout is broadly the same across the range.

What are the most common symptoms of a failed mount?
Shaking at idle in Drive, a thump on acceleration or shift, and visible engine movement under the bonnet top the list. On mounts with hydraulic fluid, you might see oily residue on the insulator. Excess vibration that disappears when you select Neutral is a classic clue.

Do all mounts need replacing at once?
Not always. If one mount is torn or collapsed, replacing that unit can restore smoothness. That said, on higher-kilometre vehicles it’s practical to assess all mounts together, if several are aged or soft, doing them as a set can save labour and give a better result for NVH and longevity.