The 7 Best Compression Testers of 2021
In the absence of proper compression, an engine cannot function correctly. Hence, if you notice a significant drop in power output, it's time to do a compression test. A compression test also helps you identify burnt valves, worn rings, and blown head gaskets.
This test assesses the engine's mechanical health by using a compression testing kit to measure each cylinder's pressure during the compression cycle. That said, a car engine in top condition should have a compression pressure of under 100 PSI per cylinder.
As this is a crucial test for your vehicle, you need to use a high-quality testing kit. In this review, we showcase some of the best compression testers in the market and explain what to consider when buying one.
7 Best Compression Testers – Review
1. Innova 3612 (Best Overall)
2. OTC 5606 (Best for Small Engine)
3. Mityvac MV5532 (Best Digital)
4. OTC 5605 (Best for The Money)
5. BlueDriver BDCT-001 (Exceptional Quality)
6. Betool HW0130 (Quick & Accurate)
7. Lisle 20250 (Basic but Effective)
1. Innova 3612
2. OTC 5606
(Best for Small Engine)
3. Mityvac MV5532
4. OTC 5605
(Best for The Money)
5. BlueDriver BDCT-001
6. Betooll HW0130
(Quick & Accurate)
7. Lisle 20250
(Basic but Effective)
1. Best Overall Compression Tester: Innova 3612
- Set Included: 15-inch rubber hose, side release valve, and adapters (12mm, 14mm, and 18mm)
Innova’s 3612 is compatible with conventional, electronic, and computerized vehicles, which means it can work for any engine, making it our best overall model. What's more, it helps identify damaged pistons, worn rings, burnt valves, and blown head gaskets.
The unit’s interface has a large and easy-to-read 2.5-inch dial face. This dial has dual calibrated and color-coded scales that give a range of 0-300 PSI and 0-2100 kPa. Hence, it is easier to get accurate readings when doing your test.
Other useful features include a quick disconnect fitting for easy installation. There is also a heavy-duty bourdon tube meter movement for high accuracy and a side release valve that allows for repeated tests without disconnecting the hose.
Though it comes with a high-pressure rubber hose and various other adapters (12, 14, and 18mm), there is no carry case. This makes it challenging to store and transport the set. But, you can get one separately without spending much.
2. Best Compression Tester for Small Engine: OTC 5606
- Set Included: 12-inch flex 14mm standard, 12-inch flex 14mm long reach, 25-inch flex hose and 10mm, 12mm, and 18mm thread adapters.
The OTC 5606 is a highly rated compression tester kit that works exceptionally well for small engines. And this can be attributed to the fact that it comes as a complete kit with multiple adapters and hoses, which will be very useful for diagnosing a small engine.
Like the Innova’s 3612 above, this model also features a 2.5-inch diameter gauge with a wide measuring range of 0-300 PSI and 0-2100 kPa. This dial has a chrome bezel, as well as a rugged outer boot for protection.
This kit includes 10, 12, and 18 mm thread adapters, which can work on flat and tapered seat plugs, making it more versatile.
In addition to this, the tester and all accessories come packed in a rugged, blow-molded hard case with a removable lid. This case helps keep all the parts organized, while also being easy to transport.
However, this kit is only suitable for domestic or import gasoline vehicles, motorcycles, and marine engines, but not diesel ones.
3. Best Digital Compression Tester: Mityvac MV5532
- Set Included: 10-inch hose, quick-change coupler, 14mm × 6.5 and 12-inch hose adapters, 18mm × 12 inch hose adapter, 18 × 14mm, 16 × 14mm, 10 × 14mm and 12 × 14mm plug adapters, and an air hold adapter.
Mityvac’s model MV5532 is a digital tester with a digital scale that gives some of the most accurate readings. Furthermore, it also allows you to store the pressure readings for up to 12 cylinders for convenient use.
This digital scale is in the form of an LCD screen, which has a backlight for easy reading from any angle and under any lighting conditions.
A power conservation feature is built-in to ensure the battery gives you extended service. This function shuts off the tester after 3 minutes without use. However, the memory part is powered throughout so that you can refer to the stored values on restarting the unit.
The tester's exterior cover is rubber, which helps to protect the gauge from drops and bumps. This protective cover combines with the grease and oil resistant face to ensure the electronics inside are adequately protected.
This kit requires a battery to run, which can be inconvenient. Luckily, the included battery lasts quite long. Also, it is relatively pricier, but the quality and performance are worth every buck.
4. Best Compression Tester for The Money: OTC 5605
- Set Included: 25-inch flex hose, 2-1/2-inch gauge, 8-inch deep well 14mm connector, 5-inch flex Ford Triton 16mm adapter, 12-inch flex-14mm standard reach, 12-inch flex-14mm long reach, 10mm, 12mm, and 18mm thread adapters, and repair parts kit.
With more items in the set than most others on our list, the OTC 5605 ensures you get great value for your money. Also, its versatile adapters are ideal for both flat and tapered seat plugs.
All the metal parts in this kit are designed for durability as they have a nickel-plated finish that offers maximum corrosion resistance for long service life. Better yet, the kit includes an extra-long 25-inch flex hose that ensures a comfortable view through the cluttered engine compartment.
With this compression tester model, you get a rugged carry case to help keep all the kit components well-organized. This case also ensures the tester and its accessories are easy to carry around.
Because the gauge will hold the pressure internally, this compression test kit cannot test for leak down. But this still does not take anything away from the fact that it is an excellent product for the money.
5. Exceptional Quality Compression Tester: BlueDriver BDCT-001
- Set Included: 2.5-inch triple scale gauge, 16-inch rubber hose, 14mm, and 18mm spark plug adapters, 8mm, 14mm, 12mm, and 10mm adapters, 45° universal direct shaft, and straight universal direct shaft.
The exceptional build quality of the BlueDriver BDCT-001 is what makes it stand out. This high-quality construction ensures the kit serves you well for many years to come.
BlueDriver BDCT-001 will accommodate all kinds of users, as it includes a triple scale gauge. This 2.5-inch gauge provides the readings in 0-300 PSI, 0-21 kg/cm², and 0-20 bar to ensure you can read it your way.
There is a decent size 16-inch rubber hose with different adapters, and the package will also have both the 45-degrees and straight universal direct shafts for maximum versatility.
One drawback of this kit is that it has just eight pieces. But while these are relatively fewer than others on our list, the good news is that it still has everything you need to do the compression test accurately.
6. Quick and Accurate Compression Tester: Betooll HW0130
- Set Included: 16-inch rubber hose, 3-inch gauge, M10, M12, M14, and M18 brass adapter and portable case.
If you are looking for a compression tester that gives you fast and accurate results, the Betooll HW0130 is a fantastic choice.
This tester comes with a larger 3-inch gauge that provides a dual-color scale to allow you to get the reading in either 0-20 bar or 0-300 PSI.
With the 16-inch rubber hose, you not only get a more flexible hose that can reach tighter areas but also a tougher one for handling greater pressure.
Motorists love that this kit is complete with various adapters for different applications and that it has a portable case for easy carry.
This compression tester will not come with long reach adapters. But, other than that, it works well enough, and you can always buy extra adapters separately. Despite not being a professional-grade kit, it is still handy for DIY uses.
7. Basic but Effective Compression Tester: Lisle 20250
- Set Included: 10, 12, and 14mm adapters
Simplicity is the one thing you can expect with the Lisle 20250. But despite the simple and basic design, it is still highly effective and accurate when testing compression.
The set includes a valve core with a color-coded dial for measuring the pressure in PSI and kPa with a range of 0-300 PSI and 0-2100 kPa, respectively.
Also included are 10, 12, and 14mm adapters, which fit a motorcycle, ATV, snowmobile, and watercraft engines, while a flexible hose gives you extended reach.
The tester does not have a side-release valve for pressure release, but it still functions well. Also, there is no carrying case. However, since the included accessories are few, carrying them around should be hassle-free.
How to Buy the Best Compression Tester
The more the tools included in the kit, the better it will be for you as it comes in handy for various uses. These extra tools allow you to conduct this test on a wide array of engines.
Besides the hose and gauge, your kit should include differently sized adapters and hoses. And even if you are shopping on a budget, make sure the kit has all the essential items like the Lisle 20250.
A gauge is the most crucial part of a compression tester as it shows you how much compression is in the engine. With that in mind, it should be large enough for easy reading and also deliver accurate readings.
Remember that there are dial and digital gauges. That said, the digital units like what you get on the Mityvac’s MV5532 are the most accurate.
These digital gauges can even store the readings for several cylinders as you conduct the compression test. However, digital testers tend to be more expensive.
A good compression tester should use premium materials for maximum durability. When choosing one, look for features such as a rubber boot for preventing damages from drops and shock. Also, a grease-oil resistant face, especially for digital units, will ensure maximum durability.
Some testers come packed in a carrying case together with the included accessories. A carry case helps ensure easy organization and transportation. Also, it protects the parts against damage, increasing the lifespan of your tester kit.
5. Ease of Use
Whether you are a beginner or experienced at using this tool, it is better to have an easy-to-use model. An easy to use kit ensures you can perform the test smoothly and accurately.
Look for features such as an easy-to-read gauge and always go for something that comes with a good manual that will provide some easy to follow directions.
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When buying a compression tester, you need to consider the construction quality, the number of fittings and ease of use to get a good one. That said, you can be sure there is something that will work for your engine on our list above.
But, to make your choice an even easier one, Innova’s 3612 takes our top overall spot. This model can work for almost any vehicle, and it is also quite versatile to allow you to accomplish various tasks.
However, for those looking for something that will give them great value for money, the OTC 5605 is perfect. The number of accessories, quality, and performance is hard to beat for its price.
- 7 Best Compression Testers – Review
- 1. Best Overall Compression Tester: Innova 3612
- 2. Best Compression Tester for Small Engine: OTC 5606
- 3. Best Digital Compression Tester: Mityvac MV5532
- 4. Best Compression Tester for The Money: OTC 5605
- 5. Exceptional Quality Compression Tester: BlueDriver BDCT-001
- 6. Quick and Accurate Compression Tester: Betooll HW0130
- 7. Basic but Effective Compression Tester: Lisle 20250
- How to Buy the Best Compression Tester