coolant reservoir cap
Worth a lookShows no brand lock-in (top 5 brands take 35% of clicks), but a small market ($73K/yr) keeps it on the watch list.
Brand share
Incredible35%top-5 brand share — no brand owns this niche
Competition
Great22%top-5 click share — an open shelf
Review moat
Great264.25avg incumbent reviews — the moat a new listing must climb
Quality gap
Great4.3★avg incumbent rating — lower means beatable quality
Conversion
Good5.3%search→purchase rate — share of searches ending in a sale
Returns
Good2.8%return rate — above 6% kills the launch gate
Price range
Okay$3.08–$20.38cheapest to priciest tracked listing — scored on the share inside $15–$100
Avg price
Bad$8.59avg listing price — sweet spot $15–$100
Growth
Bad-10.1%90-day search growth — must beat 0% to launch
Market size
Bad$73K$73K/yr · 162K searches
Competition
Clicks spread well past the top 5 (22% combined) — an open shelf where new products get seen.Brands
61 rising
Sellers
148
Top-5 brand share
35%
Open market
61%
- Dorman13%
- ACDelco7%
- ROVIKE5%
- KEVWR5%
- SWQS4%
- DeFageH4%
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 89 tracked products in this niche — three views at once, no toggling.
Top sellers
by 90-day click share
Dorman 54201 Engine Coolant Reservoir Cap Compatible with Select Models
Dorman$12.424.6★4,822 rev
2PCS Engine Radiator Coolant Water Tank Black Reservoir Cap Compatible with Infiniti Nissan Renault OEM# 21712-79900
KEVWR$6.264.4★385 rev
DeFageH 2Pcs Coolant Reservoir Cap - Premium Leak-Proof Coolant Caps for OEM# 21712-79900 Compatible with Nissan Pathfinder Maxima Murano Infiniti G35
DeFageH$4.374.6★26 rev
13502353 Coolant Reservoir Cap for Chevy GMC Buick Cadillac -Silverado 1500 2500 3500 Express Avalanche Suburban Captiva Cavalier Equinox Malibu Savana Sierra Yukon Radiator Surge Tank Cap
ROVIKE$11.524.4★162 rev
Car Radiator Cap Replacement OEM#68442532aa 53479332 Coolant Reservoir Cap Compatible with Chrysler Dodge Jeep Ram Standard Car Accessories Radiator Cover Easy to Mounting
Stacool$7.204.5★84 rev
Newest
by launch date
CCNU Coolant Reservoir Cap Replacement for Honda Odyssey 2011-2017 Acura ILX Radiator Overflow Expansion Tank Cap Replace 19102-RV0-A00 19102RV0A00 Engine Coolant Reservoir Tank Lid
CCNU$5.940 rev
4PCS Coolant Reservoir Cap Replacement OEM# 21712-79900 - Radiator Overflow Coolant Reservoir Tank Cap Compatible with Nissan Murano Rogue Versa Quest & Infiniti EX35 FX37 G35 M35
Alfaly$3.0811 rev
DeFageH 2Pcs Coolant Reservoir Cap - Premium Leak-Proof Coolant Caps for OEM# 21712-79900 Compatible with Nissan Pathfinder Maxima Murano Infiniti G35
DeFageH$4.3726 rev
Houlishu 2 Pack Coolant Reservoir Cap Replacement Universal Radiator Reservoir Cap Compatible with OEM# 21712-79900 Black Overflow Tank Cover for Water & Antifreeze
houlishu$6.0918 rev
Icyfond Engine Radiator Coolant Water Tank Reservoir Cap OEM 21712-79900 Engine Cooling System Overflow Expansion Bottle Cap Compatible with Nissan Murano Rogue Versa Infiniti
Icyfond$7.794 rev
Trending
90-day click momentumCCNU Coolant Reservoir Cap Replacement for Honda Odyssey 2011-2017 Acura ILX Radiator Overflow Expansion Tank Cap Replace 19102-RV0-A00 19102RV0A00 Engine Coolant Reservoir Tank Lid
CCNU$5.940.0★
4PCS Coolant Reservoir Cap Replacement OEM# 21712-79900 - Radiator Overflow Coolant Reservoir Tank Cap Compatible with Nissan Murano Rogue Versa Quest & Infiniti EX35 FX37 G35 M35
Alfaly$3.084.8★
Houlishu 2 Pack Coolant Reservoir Cap Replacement Universal Radiator Reservoir Cap Compatible with OEM# 21712-79900 Black Overflow Tank Cover for Water & Antifreeze
houlishu$6.093.4★
DeFageH 2Pcs Coolant Reservoir Cap - Premium Leak-Proof Coolant Caps for OEM# 21712-79900 Compatible with Nissan Pathfinder Maxima Murano Infiniti G35
DeFageH$4.374.6★
SWQS Coolant Reservoir Tank Cap for Toyota Engine Coolant Expansion Tank Cap 16471-0A030 Radiator Coolant Caps Replacement for Toyota Sienna 2004-2010 Lexus RX330 2004-2006 & RX350 2007-2009 (Black)
SWQS$9.933.0★
Demand & seasonality
Weekly Amazon search volume, last 104 weeks — -10.1% search growth over the last 90 days.No pronounced peak months · busiest ÷ quietest = 1.1×
Reviews
What buyers praise and complain about, mined from review topics.What buyers love
“Fit great”
“Quality replacement”
“Good price”
“Worked as advertised”
“Worked great as direct replacement for coolant reserve tank fill cap”
“Does the job just fine”
“No leaks so far”
“Easy installation”
“durable”
“Easy to use”
What buyers complain about
“Doesnt fit advertised to fit”
“Did not fit Suzuki Kizashi”
“Expected much higher quality from Gates”
“Not durable”
“Stop coolant loss”
“doesnt fix”
“Will leak everywhere”
“Do not believe what is advertised”
“absolute waste of money”
“It doesnt hold pressure”