Tools & Equipment
5 Best Compression Testers of 2020
In the absence of proper compression, an engine cannot function properly and if you notice a significant drop in power output, then you need to do a compression test.
Done using a compression tester, this test basically assesses the mechanical health of the engine, with the tester being used to measure the pressure on each cylinder during the compression cycle.
That said, an engine that is in top condition should have a compression pressure that is more than 100 psi per cylinder.
Since this is a very important test, you should use a high-quality unit and to help you get a good one, this review covers five of the best compression testers in the market, from which you should pick the most ideal one for your car.
5 Best Compression Testers – Review
1. Innova 3612 (Best for the Money)
2. OTC 5606 (Best Kit)
3. Mityvac MV5532 (Best Digital)
4. Innova 3615 (Best Compact)
5. Lisle 20250 (Good Quality)
1. Innova 3612
(Best for the Money)
2. OTC 5606
3. Mityvac MV5532
4. Innova 3615
5. Lisle 20250
1. Innova 3612 – Best Compression Tester for the Money
- Set Included: 15-inch rubber hose, side release valve and adapters (12mm, 14mm, and 18mm)
Innova’s 3612 is very affordable but it still has several key features that make it the top-rated compression tester in this review. Compatible with conventional, electronic and computerized vehicles, it helps identify damaged pistons, worn rings, burnt valves, and blown head gaskets.
The unit’s interface comprises of a large and easy-to-read 2.5-inch dial face, which has dual calibrated and color-coded scales that give a range of 0-300 psi and 0-2100 kPa. All these make it easier for you to get accurate readings when doing your test.
Other useful features are a quick disconnect fitting for easy installation, a heavy duty bourdon tube meter movement that gives high accuracy measurements and a side release valve that allows repeated tests without having to disconnect the hose.
Though it comes with a high-pressure rubber hose and various other adapters (12, 14 and 18mm), no carrying case is included, making it a little bit challenging to store and transport the set.
2. OTC 5606 – Best Accessorized Compression Tester
- Set Included: 12-inch flex 14mm standard, 12-inch flex 14mm long reach, 25-inch flex hose and 10mm, 12mm, and 18mm thread adapters.
In addition to this, the tester and all the included items come packed in a rugged, blow-molded hard case with a removable lid. This helps to keep all the parts organized in storage while also being easy to transport.
Part of this kit includes 10, 12 and 18 mm thread adapters, which can work on both flat and tapered seat plugs, making the kit very versatile.
Like the 3612 above, this one also features a 2.5-inch diameter gauge with a wide range of 0-300 PSI and 0-2100 kPa. This dial has a chrome bezel, as well as a rugged outer boot for protective purposes.
However, this range is only suitable to use on all types of gasoline engines such as domestic or import motorcycles and marine engines, but not diesel engines.
3. Mityvac MV5532 – Best Digital Compression Tester
- 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
Even though Mityvac’s compression tester sits in the higher end of the price range, it gives you the most accurate readings possible because it is a digital tester with a digital scale. This 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 display, which is backlit for easy reading from any angle and under any lighting conditions. However, this also means that it requires a battery in order to function.
A power conservation feature is built-in to ensure the battery gives you extended service, in which it shuts off the tester after 3 minutes without use. However, the memory part is kept powered throughout so that you can refer to the stored values on restarting the unit.
Rubber is used to make the exterior cover of the tester and this helps to protect the gauge from drops and bumps. Combined with the grease and oil resistant face, this gives it a high durability factor because the electronics inside are highly protected.
4. Innova 3615 – Small Engine Compression Tester
- Set Included: 15-inch hose, 10mm, 12mm, 14mm, and 18mm threaded adapters, 14mm and 8-inch long reach adapter
This 7-piece kit is designed specifically for gasoline engines due to its 0-300 PSI and 0-2100 kPa pressure testing range, plus the included accessories enable you to safely and easily access recessed spark plug holes, enabling you to carry out this test on all kinds of small gas engines.
These accessories include 10 and 12 mm adapters, which are a good fit for most watercraft, ATVs, snowmobiles and motorcycles, and two long reach adapters (14mm and 8 inches) for reaching deep into spark plug holes.
The 8-inch piece is actually usable with any compression tester, meaning that you can still use it if you decide to buy another tester.
A 2.5-inch dial face is used to show the results in either PSI or kPa, and it is color coded for easy reading.
Other features include a side-release valve that allows for repetitive testing without having to disconnect the hose and a direct shaft attachment for quick testing. However, a storage case is not included and thus, you must find a way to store these 7 pieces.
5. Lisle 20250 – Good Compression Tester
- Set Included: 10, 12, and 14mm adapters
Simplicity is the one thing you can expect with the Lisle 20250 and although only a few tools are included in the set, it is very affordable.
The set includes a valve core, which is the main part that has a color-coded dial for measuring the pressure in PSI and kPa on a range of 0-300 and 0-2100 respectively.
Also included are 10, 12 and 14mm adapters, which easily fit on motorcycle, ATV, snowmobile and watercraft engines, while a flexible hose gives you extended reach.
On the downside, the tester does not feature a side-release valve for pressure release and a carrying case is not included. However, since the included accessories are very few, even without a case, you can still find an easy way to store or carry them on site.
How to Buy the Best Compression Tester
This is a no brainer. The more the tools included in the kit, the better and the more you should consider buying that product. This is because these extra tools make the compression tester more versatility in its use, allowing you to conduct this test on a wide array of engines.
Apart from the hose and gauge, other tools to look for include differently sized adapters and hoses.
A gauge is the most important part of a compression tester as it shows you how much compression is in the engine. Two important things to check on this is that it should be large enough for easy reading and should deliver accurate readings.
Keep in mind that there are dial and digital gauges. Digital units are the most accurate and can store the readings as you conduct the compression test for a number of cylinders. However, they are very costly but if you can afford it, this is the best gauge to buy.
A good compression tester should be made using premium materials for durability purposes. When choosing a tester, look for features such as a rubber boot for preventing damages from drops and shocks, and a grease-oil resistant face, especially for digital units.
Some testers come packed in a carrying case together with the included tools and this helps to maintain a high level of organization in storage.
This case also protects the parts against damage, increasing the lifespan of your tester kit, while transportation to the site is made much easier.
Therefore, you should highly consider buying a compression tester that comes with its accompanying carrying case because it is an essential part of the kit. Otherwise, you will have to buy one separately later on.
5. Ease of Use
Whether you are a beginner or experienced at using this tool, it is definitely better to have an easy-to-use tester that is user-friendly so that you can perform the test easily on your own.
Ensure to look for features such as an easy to read gauge and always go through the usage instructions in the manual before use.
Read More: 10 Best Car Battery Testers
To summarize, a few factors to consider when purchasing a compression tester are the construction quality, the number of fittings and ease of use.
With these qualities, it will be easy to test the condition of your engine so as to determine the problem and make any necessary repairs.
After going through this review, you should be able to select the best compression tester that is most effective according to your needs.
- 5 Best Compression Testers – Review
- How to Buy the Best Compression Tester