radiator cap
Worth a lookShows a fragmented shelf (top 5 take 23% of clicks), but a failed launch gate (market size, growth, or returns) keeps it on the watch list.
Competition
Great23%top-5 click share — an open shelf
Review moat
Great309.48avg incumbent reviews — the moat a new listing must climb
Quality gap
Great4.3★avg incumbent rating — lower means beatable quality
Brand share
Good62%top-5 brand share — brands hold most of the demand
Conversion
Good5.6%search→purchase rate — share of searches ending in a sale
Returns
Good2.9%return rate — above 6% kills the launch gate
Market size
Okay$244K$244K/yr · 422K searches
Price range
Okay$5.07–$23.15cheapest to priciest tracked listing — scored on the share inside $15–$100
Avg price
Okay$10.26avg listing price — sweet spot $15–$100
Growth
Bad-6.4%90-day search growth — must beat 0% to launch
Competition
Clicks spread well past the top 5 (23% combined) — an open shelf where new products get seen.Brands
37 falling
Sellers
170
Top-5 brand share
62%
Open market
34%
- Gates23%
- MotoRad15%
- ACDelco10%
- Manymiba9%
- RBOKO5%
- IHOTDER5%
Product shelf
Each bubble is one product — market share against review moat; bubble size tracks estimated sales, color grades how beatable the incumbent looks.
All 92 tracked products in this niche — three views at once, no toggling.
Top sellers
by 90-day click share
Gates 31528 Standard Radiator Cap
Gates$8.474.6★683 rev
ACDelco GM Original Equipment RC27 (10409635) Radiator Fill Cap
ACDelco$10.724.7★1,950 rev
Gates 31336 Radiator Cap
Gates$12.484.4★851 rev
Car Radiator Cap Coolant Reservoir Cap OEM#16401-31520 1640131520 Standard Radiator Coolant Reservoir Tank Cap Compatible with Lexus Toyota Scion Auto Replacement Parts(for Lexus)
IHOTDER$5.964.6★152 rev
Teybouk High Pressure Radiator Cap Cover 1.8 bar Vehicle Radiator Cap Temperature Gauge 1.85 x 2.55 Water Tank Sealing Cover Universal for Suzuki Yamaha Motorcycle ATV Models (Black)
Teybouk$10.043.2★27 rev
Newest
by launch date
CCNU 1.8 Bar Radiator Cap with Temperature Gauge High Pressure Radiator Cover 25.6 PSI Water Tank Cap Universal Fit for Motorcycle ATV Dirt Bike Compatible with Honda Kawasaki Suzuki Yamaha KTM
CCNU$9.983 rev
Icyfond Car Radiator Cap Radiator Cap Replacement OEM#16401-31520 16401-31650 Standard Radiator Coolant Reservoir Tank Cap Compatible with Lexus Toyota Scion Auto Replacement Parts
Icyfond$6.012 rev
YUPIKJI Radiator Cap Engine Coolant Anti-Heat Cap Compatible with 1994-2006 Honda Accord 1992-2005 Civic 1997-2005 CRV 1995-2007 Odyssey 2003-2008 Pilot Repalces OEM# 19045-PAA-A01 19045-RAA-003
YUPIKJI$5.071 rev
KoiLuvGo Radiator Cover High Pressure Radiator Cap with Temperature Gauge 1.8 Bar High Pressure Radiator Cap Compatible with Honda Kawasaki Suzuki Yamaha KTM and More Motorcycle ATV Models
KoiLuvGo$10.976 rev
Teybouk Radiator Cap Replacement Radiator Cover 16 PSI Stainless Steel Engine Seal Cover Compatible with Dodge and Jeep Vehicles (Silver)
Teybouk$6.3710 rev
Trending
90-day click momentumCCNU 1.8 Bar Radiator Cap with Temperature Gauge High Pressure Radiator Cover 25.6 PSI Water Tank Cap Universal Fit for Motorcycle ATV Dirt Bike Compatible with Honda Kawasaki Suzuki Yamaha KTM
CCNU$9.982.5★
Racing Safety Lever Radiator Cap
MotoRad$10.744.7★
MotoRad T208 Racing Radiator cap
MotoRad$9.584.3★
Radiator Cap for Honda Acura 1995-2022 Accord 2003-2022 Pilot 1997-2020 CR-V 1995-2023 Odyssey 2006-2014 Ridgeline 1992-2015 Civic 2001-2020 MDX 2007-2024 RDX 2011-2016 CR-Z 19045-PAA-A01
Manymiba$9.753.8★
Radiator Cap - 16 PSI Original Equipment Replacement with Dual Lug Design Sealed Cooling System Pressure Cap Universal Fit for Most Cars (Silver)
LTDCVTR$6.874.2★
Demand & seasonality
Weekly Amazon search volume, last 104 weeks — -6.4% search growth over the last 90 days.No pronounced peak months · busiest ÷ quietest = 1.2×
Reviews
What buyers praise and complain about, mined from review topics.What buyers love
“Direct fit”
“The build quality feels solid”
“Worth it”
“Just as advertised”
“No leaks after installation”
“Works as intended”
“Holds pressure well”
“Works perfectly, solved my coolant odor problem”
“Easy installation”
“Well built cap”
What buyers complain about
“Didn't fit”
“Does not fit the v6 engine”
“will start to leak”
“Bad quality”
“cause all my coolant to spill out”
“False info”
“Truck overheated”
“the bar pressure is to high”
“Dose not work”
“Failed in 3 months”