This Service Bulletin provides updated non-electric water pump leak inspection and diagnostic tips for some 2008 – 2025 model year Toyota vehicles.
full bulletin at NHTSA ↗2018 Toyota Highlander engine problems
moderate Owners of the 2018 Toyota Highlander have filed 16 NHTSA complaints about the engine, typically surfacing around 20,000 miles at roughly $3,100 to repair (U.S. federal records, as of July 2026). Source: NHTSA Office of Defects Investigation. See engine across all vehicles →
Failure mileage
Complaints
16
Recalls
0
Avg fix
$3,100
| Model year | engine complaints |
|---|---|
| 2015 Highlander | 3 |
| 2016 Highlander | 6 |
| 2017 Highlander | 22 |
| 2018 Highlander (this page) | 16 |
| 2019 Highlander | 26 |
| 2020 Highlander | 3 |
| 2021 Highlander | 15 |
When does it fail?
Of the 16 engine complaints filed for the 2018 Toyota Highlander, here's the actual mileage breakdown — failures cluster heaviest at 0-25,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
What stands out
No new NHTSA engine complaint has been filed on this vehicle in over 5 years — the issue may be aging out of the active population.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering engine on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
This Service Bulletin provides updated non-electric water pump leak inspection and diagnostic tips for some 2008 – 2025 model year Toyota vehicles.
full bulletin at NHTSA ↗This is to advise of various price adjustments that will affect Toyota Genuine Motor Oil and Long Life Coolant, effective March 1, 2024. These products are ordered through the Toyota Complete Maintenance Care (TCMC) website.
full bulletin at NHTSA ↗TSB: Some 2019 ? 2022 model year Avalon, 2018 ? 2023 model year Camry, 2017 ? 2022 model year Highlander, 2017 ? 2020 model year Sienna, and 2016 ? 2023 model year Tacoma vehicles equipped with a 2GR-FKS engine may exhibit a knocking noise from the vacuum pump at idle. Follow the Repair Procedure in this bulletin to address this condition
full bulletin at NHTSA ↗TT: Some Model Year 2018-2021 vehicles equipped with A25A-FKS/FXS or M20A-FKS/FXS engines may display the following message ?Engine Maintenance Required Visit Your Dealer? on the combination meter.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Owners of 2018 Highlanders describe engine stalls, rough idle, and fuel-pump-related shutdowns—especially at low mileage. One reported an abrupt stall at a traffic light shortly after scheduled maintenance, with the check engine light activating; Toyota service suggested disabling auto-stop as a workaround and the owner tied this to recall 20TA02 (low-pressure fuel pump). Another experienced multiple no-start conditions following fill-ups, with fuel pump/vacuum codes and check engine lights; cruise control disabled when the light was on. A third reported stalling at 35 mph with check engine light. Another stalled on the highway with steering shake, brakes shake, and "low breaking power" error before the stall, with a recall notice pending a 3-4 month fix.
Oil leaks appear frequently: owners report valve cover-to-cam tower seal leaks at 52,500 miles and 4,200 miles, blamed on inadequate assembly and sealant application; one repair quote was $2,173.51. One owner found vacuum pump oil leakage. A persistent antifreeze odor from day one of ownership (no visible coolant leak) went unresolved after three dealer visits.
Low compression in cylinder #1 at 61,000 miles required full engine replacement. Water temperature sensor failure at 48,000 miles disabled AWD and stability systems; parts were on national backorder and not covered under warranty. Rough idle at 1,750 miles with RPM dropping to 500 at stops also went undiagnosed. Engine hesitation under acceleration occurred multiple times on highway, with RPM surges, and the dealer couldn't identify the cause.
Same Toyota Highlander engine reports on nearby years: 2017 · 2019 · 2021
Failure modes owners describe
Low-pressure fuel pump failure / fuel system shutdown
Engine stalls or fails to start, check engine light illuminates with fuel pump or vacuum-related codes. Stalls occur at traffic lights, fill-ups, and while driving at highway speeds. One owner tied this to NHTSA recall 20TA02.
When: As early as 20,000 miles; multiple occurrences through 70,000+ miles
Symptoms owners cite: Abrupt engine stall; No-start condition after refueling; Check engine light; Steering wheel lock; Cruise control disabled when light on; Low breaking power warning
Codes mentioned: Fuel pump/vacuum code, Check engine light (P0300 range implied)
Repairs/costs cited: Toyota service recommended disabling auto-stop feature as temporary measure. One owner was told parts were on backorder; another's recall status was unresolved for 3–4 months.
Recalls/TSBs owners mention: NHTSA campaign 20V012000 (fuel system, gasoline); recall 20TA02 (low-pressure fuel pump may stop operating). Toyota offered workarounds rather than timely repairs and charged diagnostic fees for recall-related issues.
Valve cover / cam tower oil leak
Oil leakage from valve cover-to-cam tower seal due to inadequate assembly and sealant application. Leak worsens over time and becomes visible after several years despite regular maintenance.
When: 4,200 miles and 52,500 miles; likely present from factory but not noticeable until years later
Symptoms owners cite: Oil leak from engine bay; Potential smoke and burning odor on hot engine components; Fire risk from oil on hot surfaces
Repairs/costs cited: Valve cover assembly and gasket replacement quoted at $2,173.51 by Toyota dealer. Owner performed repair at local shop after Toyota refused coverage.
Recalls/TSBs owners mention: Toyota of America refused assistance despite leak occurring within 60,000-mile powertrain warranty window but outside 60-month time limit. No recall issued.
Vacuum pump oil leak
Oil leakage from the vacuum pump requiring component replacement.
When: 2 years / early ownership
Symptoms owners cite: Oil leak from vacuum pump
Repairs/costs cited: Local body shop diagnosed; replacement required.
Engine gasket seal failure
Engine gasket not sealed correctly at assembly, causing fluid leakage.
When: 4,200 miles
Symptoms owners cite: Fluid leak from engine
Repairs/costs cited: Repaired at Toyota of Bowie (16700 Governor Bridge Rd, Bowie, MD 20716).
Recalls/TSBs owners mention: Manufacturer notified; vehicle repaired.
Low cylinder compression
Low compression detected in cylinder #1, requiring complete engine replacement. Failure cause not explained by owner.
When: 61,000 miles
Symptoms owners cite: Check engine light; Low compression in cylinder #1
Repairs/costs cited: Full engine replacement required. Vehicle not repaired; owner referred to NHTSA Hotline.
Recalls/TSBs owners mention: Manufacturer opened case and referred owner to NHTSA Hotline. No warranty coverage or remedy offered.
Water temperature sensor failure with disabled stability systems
Water temperature sensor failure causes the onboard computer to disable AWD and stability control. Dealer applied temporary fix (plastic on grill) but failure recurred multiple times.
When: 48,000 miles
Symptoms owners cite: Check engine light; AWD system disabled; Stability control disabled; Warning message on display
Repairs/costs cited: Temporary repair applied (plastic shielding on grill); permanent replacement required but parts on national backorder.
Recalls/TSBs owners mention: Manufacturer stated parts not covered under warranty. Attributed failure to weather and cold air intake.
Rough idle and RPM drop at stops
Engine RPM drops to near 500 when brakes are engaged at stop lights; vehicle idles rough and attempts to stall. Shifting to neutral restores normal RPM and smooth idle.
When: 1,750 miles (near-new condition)
Symptoms owners cite: RPM drops to ~500 at stops; Rough idle; Stalling attempts; Normal RPM when in Neutral
Repairs/costs cited: Dealer advised no problem found on first visit. Owner returning for second attempt.
Recalls/TSBs owners mention: Auto-stop feature confirmed off. Dealer unable to replicate or diagnose.
Engine hesitation and RPM surge under acceleration
Hesitation when pressing gas pedal, particularly during highway passing attempts. RPM surges (to 5,500 and 4,000 noted) then vehicle engages after delay. Owner reports it felt like the engine would 'blow up.'
When: Early ownership (incidents on 3/20)
Symptoms owners cite: Hesitation when accelerating; Unpredictable RPM surges; Delayed throttle response
Repairs/costs cited: Dealer service manager confirmed the hesitation during ride-along but vehicle remained undiagnosed and at dealership.
Persistent antifreeze odor without visible leak
Strong antifreeze odor from driver-side exterior, present from day one of ownership. No visible coolant leakage on pavement or in engine bay; no heater core odor inside cabin.
When: From first day of ownership (07/27/2018); 8 months old with 4,800 miles
Symptoms owners cite: Pungent antifreeze odor (exterior, driver side); No visible coolant leak; No interior heater core odor
Repairs/costs cited: No solution found after three dealership visits.
Synthesized from 16 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 3 most recent
Vehicle was driving on street and check engine light came on. Took vehicle to service provider and is related to recall. No remedy for recall has been developed -- currently driving a loaner car.
Wife was driving and out of nowhere axle to the transfer case broke leaving her stranded in the middle of the road. Seems like transmission had been a common issue in these vehicles around the same year
After vehicle has warmed up engine RPM speed drops to near 500 when brake engaged at stop lights and vehicle idles rough and attempts to stall. Shifting to neutral brings RPM speed back up and idles smooth again. Problem occurs daily over last two months. Vehicle is near new, 1750 miles. Auto stop start feature is not engaged. Taken to dealer who advised no problem found. Returning to dealer…
Had engine trouble with your 2018 Toyota Highlander?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the engine problem on the 2018 Toyota Highlander?
It's a documented issue but not catastrophic. 16 complaints have been filed. Repairs average $3,100 and most owners catch it before it causes a breakdown.
At what mileage does the engine typically fail?
Across the 10 complaints that reported odometer mileage, most engine failures cluster between 10,999 and 37,000 miles, with the median around 20,000. A quarter of owners report trouble before 10,999; a quarter make it past 37,000. Maintenance history matters more than the odometer alone — this is the reported failure window, not a guarantee.
What does it cost to fix?
Independent shops typically charge around $3,100 for engine repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to engine?
No active recalls currently cover engine issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2018/Toyota/Highlander.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.