Every oil extractor gets a score from 0 to 100% built from five factors, which maps onto the 5-point rating shown on the site (a 0% score would be 1.5 stars; a perfect score, 5). Each factor is scored against fixed reference points, not against the other products in the list, so adding a new model never moves another model’s rating. Extractors are grouped by type (hand pump tanks, pneumatic tanks and 12 V electric pumps) and ranked within their group.
| Factor | Measures | Weight |
|---|---|---|
| Price | current price | 30% |
| Capacity | tank capacity for vacuum extractors, rated flow for electric pumps | 25% |
| Tube kit | suction tubes in the box (vacuum tanks) or suction hose length (electric pumps) | 15% |
| Features | overflow shutoff, no compressor needed, pour spout and dispensing (tanks); 12/24 V, case and hose plugs (electric pumps) | 15% |
| Warranty | warranty length | 15% |
Where the numbers come from
Capacity, flow, tubes, features and warranty come from the maker’s product copy, including the maker’s own copy on a retail listing, and for some models a parts distributor’s copy of the maker’s specifications. Figures given in gallons or quarts are converted to liters. Where a listing gives two figures that conflict, neither is used. Prices are checked at Amazon and the maker’s own store, and the lowest price at a store the page links to is used.
The factors
Price is the current price on a log scale, so halving the price always counts the same: $200 scores zero and $50 full marks.
Capacity is the tank capacity for vacuum extractors: 4 L scores zero and 15 L full marks. Electric pumps have no tank, so this factor uses the maker’s rated flow instead: 1 L a minute scores zero and 6 L a minute full marks. Where a maker gives a range, such as 1 to 4 L a minute, the top figure is used, which assumes warm oil.
Tube kit is, for vacuum tanks, the number of suction probes or extension tubes in the box that go down a dipstick tube, not counting the main hose or a brake bleeding hose: one tube scores zero and four full marks. For electric pumps it is the suction hose length: 36 in scores zero and 72 in full marks.
Features for vacuum tanks is 45% for an overflow shutoff, 25% for working without a compressor (every hand pump tank, and pneumatic tanks with a hand pump), 15% for a pour spout and 15% for being able to pump fluid back out. For electric pumps it is 40% for running on 12 V and 24 V, 30% for a storage case and 30% for hose plugs that stop drips in storage. A feature the maker doesn’t mention counts as absent.
Warranty is the maker’s warranty: none scores zero and 3 years or a lifetime warranty full marks.
What isn’t scored
Weight, the thinnest probe’s diameter, hose length on vacuum tanks, air pressure, motor power, release date and pneumatic flow figures are listed but not scored. The thinnest probe matters for fit on your engine, so check it on the product page.
Missing data
Capacity is the factor that most separates these products, so a tank without a published capacity, or an electric pump without a published flow rate, scores zero on it and the product page marks it as estimated. The same goes for warranty: a maker that doesn’t publish one gets no warranty counted. If the tube count or hose length isn’t published, that factor gets the neutral middle score (50) and is marked estimated.
Ties and discontinued models
Products are ranked by score within each group. Discontinued models stay listed but rank below every current model and can be hidden with the “Hide discontinued” filter.