5w40 engine oil
Worth a lookShows low returns (0.6%), but strong incumbent ratings (4.8★) keeps it on the watch list.
Returns
Incredible0.6%return rate — above 5% kills the launch gate
Avg price
Incredible£23.02avg listing price — sweet spot $15–$100
Price range
Great£7.44–£42.20cheapest to priciest tracked listing — scored on the share inside $15–$100
Conversion
Good6.8%search→purchase rate — share of searches ending in a sale
Growth
Okay+19.2%90-day search growth — must beat 0% to launch
Review moat
Okay1,728.29avg incumbent reviews — the moat a new listing must climb
Market size
Okay£188K£188K/yr · 119K searches
Competition
Okay63%top-5 click share — leaders hold, buyers still browse
Brand share
Bad93%top-5 brand share — brand-locked demand
Quality gap
Bad4.8★avg incumbent rating — lower means beatable quality
According to Flapen's Amazon United Kingdom niche tracking, 5w40 engine oil is a £188K/yr Amazon United Kingdom market (119K searches/yr). The top 5 brands hold 93% of demand. Verdict: Worth a look — 50/100.
Data updated Jul 18, 2026 · scored weekly · How we score niches
5w40 engine oil market data
- Units sold / yr
- 8K–10K
- avg 250–500/product
- Revenue / yr
- £184K–£230K
- units × avg price
- Conversion rate
- 6.8%
- Avg BSR
- #93
- Page quality
- 0%
- Prime
- 100%
- Sponsored
- 82%
- Out of stock
- 9.1%
- Avg brand age
- 88 months
- Avg seller age
- 190 days
Competition & brand share
The top 5 products take 63% of clicks — established leaders, but buyers still shop beyond them.Brands
8 falling
Sellers
53
Top-5 brand share
93%
Top 20: 100%
Top-5 click share
63%
Top 20: 100%
Open market
4%
- Castrol71%
- Redex7%
- Carlube6%
- Liqui Moly6%
- TotalEnergies3%
- Comma3%
- Open — no brand owns it (2 brands, 4%)
Demand & seasonality
Weekly Amazon search volume, last 104 weeks — +19.2% search growth over the last 90 days.No pronounced peak months · busiest ÷ quietest = 1.4×
Top 5w40 engine oil search terms
- 5w40 engine oil44K/yr
- 5w4014K/yr
- 5w 40 fully synthetic engine oil12K/yr
- castrol edge 5w409K/yr
- engine oil 5w409K/yr
- 5w40 engine oil fully synthetic9K/yr
- 5w-40 engine oil6K/yr
- 5w 40w engine oil5K/yr
- 5w 404K/yr
- 5w40 oil4K/yr
Top 5w40 engine oil products on Amazon
Each bubble is one product — market share against review moat; bubble size tracks estimated sales, color grades how beatable the incumbent looks.
All 17 tracked products in this niche — three views at once, no toggling.
Top sellers
by 90-day click share
Castrol EDGE 5W-40 Advanced Fully Synthetic Engine Oil Meets ACEA C3 & API SN/CF Specifications 4L
Castrol£25.994.8★1,123 rev
Castrol EDGE 5W-40 Advanced Fully Synthetic Engine Oil Meets ACEA C3 & API SN/CF Specifications 1L
Castrol£10.944.8★1,123 rev
Castrol EDGE 5W-40 Advanced Fully Synthetic Engine Oil Meets ACEA C3 & API SN/CF Specifications 5L
Castrol£33.694.8★1,123 rev
Redex 5w-40 Fully Synthetic Engine Oil MB VW RN 2 Litre
Redex£14.614.7★127 rev
Castrol MAGNATEC 5W-40 C3 Engine Oil 4L
Castrol£24.484.8★260 rev
Newest
by launch date
MOTORWORLD Fully Synthetic C2/C3 Engine Oil 5W-40 Advanced Full Synthetic Motor Oil for Petrol & Diesel Engines Low SAPS ACEA C2 C3 Approved 5L
Motor World£24.7419 rev
Castrol MAGNATEC 5W-40 C3 Engine Oil 4L
Castrol£24.48260 rev
Castrol EDGE 5W-40 Advanced Fully Synthetic Engine Oil Meets ACEA C3 & API SN/CF Specifications 4L
Castrol£25.991,123 rev
Castrol EDGE 5W-40 Advanced Fully Synthetic Engine Oil Meets ACEA C3 & API SN/CF Specifications 1L
Castrol£10.941,123 rev
Castrol EDGE 5W-40 Advanced Fully Synthetic Engine Oil Meets ACEA C3 & API SN/CF Specifications 5L
Castrol£33.691,123 rev
Trending
90-day click momentumCastrol MAGNATEC 5W-40 C3 Engine Oil 4L
Castrol£24.484.8★
LIQUI MOLY Synthoil High Tech 5W-40 | 5 L | Synthesis technology motor oil | SKU: 1856
Liqui Moly£37.834.7★
Castrol EDGE 5W-40 Advanced Fully Synthetic Engine Oil Meets ACEA C3 & API SN/CF Specifications 5L
Castrol£33.694.8★
Castrol EDGE 5W-40 M Advanced Fully Synthetic Engine Oil Meets ACEA C3 & API SN Specifications 5L
Castrol£42.204.9★
Castrol MAGNATEC 5W-40 DPF Engine Oil 1L
Castrol£7.444.7★
What buyers say about 5w40 engine oil
What buyers praise and complain about, mined from review topics.What buyers love
“Good price”
“Good quality oil”
“Great oil choice”
“As expected”
“Strong, reliable oil for smooth engine performance”
“Runs smooth in my car”
“very confident it will increase engine longevity”
“It worked, no more light on, better performance, engine not as noisy”
“Ease of use”
“The engines purr - good item / good price”
What buyers complain about
“While the price point is a bit higher”
“My car never consumes oil”
“Disappointed happy with the quality”
“This version doesnt seem to have titanium”
“Not really a perfect fit”
“Unfortunately, although this is described as Fully Synthetic, nowhere are these words to be found on the item itself, which makes you doubt that it is, in the absence of any reassurance from any source”
“These bottles don't have a built in spout so you'll definitely need a funnel to prevent spillages”
“too thick”
Top return reasons
Common questions
- Is 5w40 engine oil profitable to sell on Amazon United Kingdom?
- The niche generates £188K/yr across 17 tracked products. 90-day search growth is +19.2%. Flapen's verdict: Worth a look (50/100).
- How competitive is the 5w40 engine oil niche?
- 8 brands and 53 sellers compete. The top 5 products take 63% of clicks and top 5 brands hold 93% of demand.
- What do buyers complain about in 5w40 engine oil?
- Top complaints mined from reviews: Value For Money, Lubrication, Quality-Overall. The return rate is 0.6%.
- When does demand for 5w40 engine oil peak?
- Demand is steady year-round — the busiest month runs 1.4× the quietest.
- What does it cost to enter the 5w40 engine oil niche?
- Listings span £7.44–£42.20; the average listing price is £23.02 (sweet spot $15–$100). The average incumbent carries 1,728 reviews — the moat a new listing must climb.