There are any number of ways to get a looking into what is going on in your engine. They range from being as simple as merely listening to your engine to hear if things are sound right to taking your engine entirely apart. While disassembling your engine may be a way to be sure what is happening inside, it takes plenty of space, some special tools and quite a bit of time.
On the other hand, listening is quick and easy, but might not be the most informative tool at your disposal. Somewhere more toward the middle of the spectrum would be hunting down the best compression tester that you can.
These devices let you pull out a spark plug (and remember to disable your fuel pump) to make sure the engine is getting the proper compression for that cylinder. Sure, you’ll have to do a minimal amount of work, but you will be rewarded with hard data that can give you a definitive answer as to if there is a problem in the system.
Also, it gives you the chance to test regularly which can provide you with data as to how your vehicle performs. Frequent testing may also let you spot a problem before it becomes too much of an issue.
The Best Compression Tester – Quick Comparison
Before we dive in into details, for those of our readers who don’t have time going thru the entire post, here are the TOP picks of what we consider to be the best compression testers (plus, you will find individual product reviews in the following sections of this post). Here we go:
|editors-choice||Best Product||Best Value|
|editors-choice||Best Product||Best Value|
|item-title||Mityvac MV5532 Digital||INNOVANT||INNOVA 3612||INNOVA 3615 OHC||Actron CP7828A||OTC 5605 Deluxe|
|• digital gauge|
• number of adapters and hoses
• molded plastic case
|• 9 piece kit|
• up to 300PSI
• molded plastic case
|• 4 piece kit|
• up to 300PSI
|• 7 piece kit|
• up to 300PSI
• side-release valve
|• number of adapters|
• up to 300PSI
• storage pouch
|• number of adapters
• up to 300PSI
• molded plastic case
The Guide: What To Look For by Choosing the Best Compression Tester
What Should the Best Compression Tester Kit Include?
When you start looking for the best engine compression tester the easiest thing to look at is what does the kit contain. You’ll want to make sure that you have the correct pieces to work with your car.
The first and easiest thing that you’ll notice is the engine compression gauge. Most are a dial gauge, but you may find other types, such as digital offerings. You will want to make sure that the gauge is easy for you to read. These kits will also come with some number of high-pressure hoses. These will lead from the spark plug area to your gauge. Some kits will offer you a number of lengths to match different engine layouts.
Finally, the kit will have some number of adapters to attach to the spark plug port. More adapters mean that it will be able to work with more different cars.
How Do Engine Compression Testers Work?
The piston in your engine is used to compress a fuel and air mixture. The air is pulled in from the outside and the fuel is delivered from the fuel pump. When the mixture is properly compressed the spark plug will provide the spark and the mixture will explode, driving the piston down and providing power for the engine.
Problems can arise if the compression is off, though. Too low and the explosion won’t push the piston as much and you’ll get less power. These devices hook into the spark plug port and measure the level of compression.
Using Your Engine Compression Test Kit
Please remember that you will be working on the part of the engine where the fuel is ignited. You want to keep that in mind as you begin work.
First, you will want to stop the fuel from entering the cylinder. This can normally be accomplished by removing the fuse that runs the fuel pump. Alternatively, you can unplug the fuel line from the engine, if you go this way remember that the fuel pump may still be pumping fuel. Next, you will want to remove the spark plug from the cylinder that you are testing.
The best engine compression testers will have a range of different adapters to make sure that you have the right one to match with your vehicle.
Once your tester is hooked up with the gauge where you can easily read it you’ll want to crank the engine several times. The first time or two won’t have the full compression, which is the number you are looking to check, three to four times should be enough.
You’ll want to be sure to take an accurate reading from each port. It is always a good idea to note your readings down. If you have a tool with an analog dial you want to make sure that you read the dial looking straight at it (parallax error). Reading from the side may cause you to read a value that is too low or too high. You can look up what a good value for your engine is, but in general, you’ll want to see values that are above 100 psi.
Taking Care of Your Tester
One thing that you must take into consideration is taking good care of this tool. While a drop or hard hit can cause the gauge to go out of alignment, this isn’t a common problem.
A bigger concern is that your testing hoses remain in good condition. Since this is a tool that deals with highly compressed air a weak spot or a hole could result in part of the hose suddenly giving way. Some of the best compression tester kits will have a case that will store your kits pieces while also keeping them safe from getting worn down.
Our Top Picks – Reviews and Recommendations of the Best Engine Compression Tester Kits
Now that you know how useful an engine compression tester is you’ll want to search for the best one out there. Luckily, we have done the hard work and come up with six of the top choices that are currently available on the market.
Remember that as these are designed for testing compression but the best diesel compression tester cannot work on gasoline engines as long as they need to cover a might higher level of compression.
As normal we will point out the Best Value choice and the Best Product choice. So without any further delay let’s take a look at some of these options.
Mityvac MV5532 Digital – Our Best Compression Tester Kit Choice
The Mityvac MV5532 Digital Compression Test Kit is a high-quality kit designed to work with gasoline engines. This kit swaps the dial gauges for a digital one. In addition to making it easier to read this also means that it can not only display the pressure but it can store the highest pressure it hits. Normally the pressure will slowly begin to drop as the value reopens, so testing with a single person can be difficult, but this set up solves that problem.
This not only comes with a standard complement of adapters but also features a number of differing lengths of hose to make it easier to get to any ports that might otherwise be hard to reach.
One of the things that those in the running for best engine compression tester tend to come with is a case. This one does, which makes sure you can keep it safe and secure and quickly see if any of the smaller pieces are missing or still being used.
One note is that this device will need to be calibrated to remain accurate, luckily it doesn’t need to be returned to the company. A set of instructions for this task are included and the process is simple. This kit has the high-quality extras, like recording the highest pressure for each test that make it a no-brainer for our pick for the best engine compression tester kit.
Check the current price on Amazon
INNOVA 3612 – Best Compression Tester for the Money
The INNOVA 3612 Compression Tester is a four piece set that offers you an analog style gauge. This gauge goes up all the way to 300 PSI, which gives you a good range of pressure to read. The dial also has a range that is colored red and then one that is colored green, so you can get a good idea if things are going well or not without having to read off an exact number. The hose is 15 inches long to give you a fair amount of distance to go from the port to the gauge and still be able to read it easily.
This kit gives you the options of adapters that are 14 mm, 16 mm and 18 mm. These allow you to test not only automobiles but also motorcycles, ATVs, and even snowmobiles. This makes for a very versatile tool. In fact, it should be able to work with just about anything that takes a spark plug.
One downside to this set is that it is just loose pieces, so you’ll have to find a good place to store them. But at this price point for the level of versatility, it is no wonder that this is our pick for the best compression tester for the money.
Read customer reviews on Amazon right here
INNOVANT Compression Tester
This 9 piece Compression Tester from INNOVANT offers you quite a few bells and whistles that other kits might leave out. To begin it offers a good selection of threaded adapters, this particular kit covers 8 mm, 10 mm, 12 mm, and 14 mm. Then to cover other options where you might not have a threaded connection, this kit offs two rubber cone push connectors. One is straight and one is angled to help you easily reach the opening. These all connect to the 18-inch connector hose which is used to link the adapters to the analog dial. This dial is marked off in PSI up to 300 and also the inside is marked in kPa (here you can easily convert them).
In addition, the kit offers you a molded plastic case to keep everything in place and secure when not in use. Then to add another diagnostic tool to your kit, this set up gives you an inline ignition spark tester connector to let you easily check that you are in fact getting a spark.
The company also points out that none of these should be tightened more than finger tight, as doing so could cause the o-rings to break. In our research, we have also found that the company has a rather good and responsive customer service department.
Check it out on Amazon
INNOVA 3615 OHC Compression Tester Plus – 7 Piece Kit
The INNOVA 3615 OHC Compression Tester Plus is a 7 piece kit that you should consider if you are in the market. This kit has clearly been crafted to last you a while. The 15-inch high-pressure hose has stainless steel casing around it to keep it safe from being pinched, worn down or cut. The kit comes with threaded adapters in 10 mm, 12 mm, 14 mm, and 18 mm. It also offers a not threaded quick attachment in the 14 mm size so that you can quickly attach and test any opening.
While this kit does not come with a case it is clearly built to last. It has a metal 8 inch, long reach adapter that can be used with any engine compression tester for when you need a few more inches of reach. The gauge for this one is another analog affair, ranging up to 300 PSI, with the kPa on the inside to give you another set of values. The main hose is 15 inches long.
The whole kit has been designed to help the user get easy access to those difficult to reach spark plug ports. The gauge’s adapter has a side release valve so that you have the ability to run several tests without having to disconnect the whole set up to relieve pressure.
Check it on Amazon right here
Actron CP7828A Professional Compression Tester
The Actron CP7828A Professional Compression Tester is one that is built to last and give you years of service. It sports an analog gauge that goes all the way to 300 PSI. Like most dial gauges it also sports markings inside that give you values in kPa. Unlike some other gauges, this one doesn’t seem to have the color markings to quickly let you know if the pressure is good or too low.
This gauge also has a ring of protective plastic armor around it to keep it safe from falls and bumps. It features a number of adapters, a 10 mm, 12 mm, 14 mm, 14 mm long reach and an 18 mm threaded spark plug adapter. All of this can fit into the provided storage pouch.
In addition, this kit comes with a repair kit. That kit has extra valves and O-rings so that if something goes wrong you can easily swap them out and continue to work. One thing to note is that at times some of these adapters have been known to get stuck. When you go to remove them the hose will come, but the actual adapter stays in place and is difficult to remove. Be sure to exercise caution while removing the set up once testing is completed.
Check the latest price on Amazon
OTC 5605 Deluxe Compression Tester Kit
The OTC 5605 Deluxe Compression Tester Kit is one that has quite a few tricks up its sleeve. All the connectors are finished with a corrosion resistant nickel plate to keep them in top condition.
The set comes with a 10 mm, 12 mm and 18 mm threaded connectors as well an 8 inch deep well 14 mm connector, 12 inches flexible 14 mm connectors (in both standard and long reach) as well as offering a 5 inch 16 mm connector for the Ford Triton.
This setup sports an analog dial gauge that offers measurement from 0 to 300 PSI and 0 to 2100 kPa.
The compression tester kit comes in a molded plastic case which features a removable top to allow everything to be quickly accessible while working. Then you can replace the lid and all of your pieces will be securely held in place and safe for storage.
The kit also gives you a repair kit, so if there are some O rings that go out you will be able to quickly replace them and continue on with your tests. With all the adapters this offers you, you should be able to test pretty much any engine that has a spark plug.
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This is a tool that if used improperly can result in damage to your vehicle or even injury to yourself. We would urge you to take the correct steps, such as making sure that you have a plan in place to keep fuel from ending up where you don’t want it.
Also, be sure that you give your tool a check before using it, as a worn down spot in the hose can cause it to fail suddenly and possibly launch pieces around your garage.
Bottom Line – Wrapping Up Our Search for the Best Compression Tester
Now you should be armed with everything that you need to make your selection for the best compression tester. Based on the kinds of data you get when you test all of your cylinders you will be able not only tell if things are going wrong in your engine, but you’ll also be able to narrow down it to a few different problems, such as poor engine compression, stuck piston or bad value. With proper care, you will be able to use any of these options for years to come on any different number of vehicles.
Remember, that diesel engines work with much higher compression so they need dedicated diesel compression tester. All of our choices are designed for gasoline engines.
If you just want a quick easy answer for which to go with, you can’t get any better than the offering from Mityvac. It is the only digital gauge to make our list, which gives it the ability to do a number of useful things. By far, the best thing it does if you are working on your own is to store the highest pressure from each different test that you run, so that you are sure that you are getting true values.
Go and check all compression testers available on Amazon
Next, it is your turn. We’d love to hear from you which option you went with and why in the comments section below.