The compression tester is an invaluable diagnostic tool designed to check out a number of problems that may be wrong with your diesel engine. Also known as a compression test gauge, this tool is extremely useful in performing pressure checks on your engine.
For the continued health of your engine, the best way to check without getting too invasive is by using a pressure testing kit. The kit typically consists of a high-pressure hose, a gauge, and fittings to match the gauge to the spark holes.
When purchasing a compression tester, you will typically want to choose one that fits a variety of car models and a gauge that goes up to 1000 PSI to cover the high pressure produced by diesel engines.
A compression kit is a tool that every mechanic and household should have, as it is quite inexpensive and can be a lifesaver. We have outlined five best compression testers you can buy for your diesel engine.
Our Top 5 Diesel Compression Testers
|Mityvac MV5532 Digital|
|OTC 5021 Universal Diesel Engine Compression Gauge|
|14 Piece Diesel Compression Tester Set for Cars, Trucks, Tractors|
|PMD Products Diesel Engine Compression Cylinder Pressure Tester Gauge Kit 0-1000psi TU-15|
|K&A Company Diesel Engine Compression Tester Test Set Kit 0-1000 PSI Copper Steel New with Case|
1. Mityvac MV5532 Digital – The Most Accurate Test KitMost people would shy away from the hefty price tag of the Mityvac MV5532 Digital, but we have tested this device and found out that it is worth every penny.
With this testing kit, you get a digital screen that narrows down the pressure reading to one decimal place and wants to be the only kit you will ever buy. The MV5532 reduces the hassle and stress that comes with most kits as it is well equipped with five rubber pressure hoses of varying lengths and lengthy adapters.
If it’s your first time using a compression tester, you will definitely appreciate the ease of use and the instruction manual that comes with step by step directions. The highly durable material coupled with the hard case prolong the lifespan of this kit even further.
2. OTC 5021 Universal Diesel Engine Compression Gauge – The Universal Diesel Engine TesterThe OTC 5021 Universal Diesel Engine Compression Gauge is one of the best gauges that you will get that is reasonably priced, offers good quality, and is capable of reading up to 1000 PSI.
The hose end of the gauge has a check valve button included and a quick disconnect fitting. Amongst the included accessories is a much-needed straight and 45-degree hose connectors that enable you to reach the spark plugs.
3. 14 Piece Diesel Compression Tester Set for Cars, Trucks, Tractors – Best Professional KitIf you work on a variety of trucks or are a professional mechanic, you will surely need the 14 Piece Diesel Compression Tester Set. This kit contains all the adapters that you will ever need when attending to trucks, tractors, cars, and anything that runs on diesel.
In addition to having numerous adapters, this tester comes with a hassle-free swivel-end and quick–coupler that allows you to connect and disconnect adapters. The gauge has a release valve included, and the hose is 14.5 inches long to ensure that it reaches the concealed parts in the engine bay.
This compression tester can go up to 1000 PSI, which is the recommended pressure level for diesel engine tester kits.
4. PMD Products Diesel Engine Compression Cylinder Pressure Tester Gauge Kit 0-1000psi TU-15 – The Durable KitThe PMD Diesel Engine Compression Cylinder Pressure Tester Gauge Kit is a 12-piece tester that scales from 0 to 1000 PSI. The tester kit has a readable 2.5-inch gauge with a push button air release.
The most intriguing aspect about this particular kit is the rugged built quality of every facet that comes in the case. The 15-inch adapter is made of flexible and equally durable material that enables it to reach the hidden spark plugs.
Like most professional kits, this one comes with 12 adapter pieces that enable you to work with a variety of car models without necessarily buying extra adapters.
5. K&A Company Diesel Engine Compression Tester Test Set Kit 0-1000 PSI Copper Steel New with Case – The Budget KitLike the 14 Piece tester above, the K&A Company Diesel Engine Compression Tester is built for professionals and comes with all the necessary components you will need for diesel-fueled trucks, tractors, and cars.
This compression tester is constructed from durable copper and steel around the adapters and fittings included. In addition, the oversized gauge is chrome plated in order to give accurate measurements that are easier to read.
This is a must-buy for any serious mechanic because you get an additional swivel-end quick-coupler for easy connecting of adapters at a fraction of the price of other testers in the market.
The K&A Company Diesel Engine Compression Tester Test Set Kit is a major steal considering the fact that it included 13 adapters in the travel case included. The K&A kit really impressed us by the number of equipment they threw in and the quality of items included.
Factors to Consider When Buying the Best Diesel Compression Testers
Before we look at what you should consider when buying a diesel engine compression tester, it is paramount that you learn the testing procedures and how the compression testers work.
The process is fairly simple, and you should be able to conduct this on your own rather than taking your car to the mechanic.
How do diesel compression testers work?
First things first, the engine operation involves the piston which is used to compress a mixture of fuel and air in the combustion chamber. In this very chamber, air is drawn from the outside and fuel from the fuel pump.
The mixture is normally put under high pressure from the pistons upward movement and the park plug release a spark that causes the mixture to explode. This, in turn, drives the piston down thus providing power for the engine.
Problems normally arise when the compression is off. Very low compression will cause the engine to work inefficiently as the power drawn would be minimal, and will therefore have to work for longer to generate the same amount of energy.
The compression testers now hook onto these spark plugs ports in order to measure the level of compression. The compression measurement should be taken when you crank up the engine three to four times in order to get the full compression.
Although this varies slightly from one diesel engine to another, the general procedure involves:
- Disabling the fuel injection: This can either be done by removing the fuel fuse or disconnecting the fuel supply altogether.
- Secondly, removing all the glow plugs; this is to reduce the emanating compression pressure.
- Using the correct adapter from the compression tester, thread it into the glow plug hole. Ensure that the gauge attaches to the plughole through the adapter firmly.
- Make one last check to verify that the ignition is disabled so that the engine does not start.
- Activate the starter directly by use of a test jumper.
- Crank the engine 4-5 revolutions in order to get the maximum compression.
- Read the PSI figure on the gauge straight to prevent parallax error and record it.
- Repeat this for all the other cylinders and compare compression pressures.
If you are still having a torrid time choosing the best diesel compressor for your engine, the following guideline will lead to the right choice should you choose to pick a compressor outside the five mentioned above.
Engine Compression Gauge
The compression gauge is the calibrated face where you take your readings from after cranking up your engine during testing. Most compression kit gauges are dial or analog in nature, but you will find a few that are digital. One good example of a digital gauge kit is the Mityvac MV5532 Digital.
One major advantage that comes with a digital gauge is increased readability and accuracy in measurement. To be precise, a digital gauge can narrow down a measurement to the nearest .0.
A good compression test kit should have a number of adapters in order to fit different car models. Make sure to go for a kit that has a full assortment of adapters to fit both the standard plug and the lesser common sizes as well.
The adapters included are just as good as their length. The spark plugs can be quite cumbersome to reach, and the testing process will be more enjoyable with a 15-inch long adapter. The most common adapters measure 10mm, 12 mm, 14 mm, or 18 mm in width.
Because you are not an expert in mechanics and do not have the time to go through all the available options, it is wise to consult. The feedback from experts or users will help in evaluating the available options.
This will also help narrow down your options with the numerous compression testers out in the market.
Many models come with a hard case included. A hard case is better than no case as it helps you stay organized and quickly find the required adapters if need be.
The fact that you can store all parts in a single bag also means that they can easily be ported to the testing site.
With many compression tester kits, this is normally the hose and gauge. Other models come with a little bit more included. All in all, the included components have to be of good quality. Readability is increased with a 2.5 inch calibrated gauge that shows pressure in both PSI and kPa.
The hose is something that you will twist and turn frequently in order to reach the inaccessible engine bay. For durability go for a hose that has a steel casing to prevent the hose from being worn out or cut by engine parts.
Ease of Use
The good thing about the entire process of compression testing is that you can do it yourself. This erases the need to approach the neighborhood mechanic and also saves on a few coins.
Compression testing is a simple DIY project and is made easier with detailed instructions from the manufacturer.
When purchasing a compression tester make sure to look for one that can withstand use and abuse over time. The components should be durable enough to serve you for over one year at best.
From the hose fittings, adapters to the gauge itself they should be made from premium materials and be rugged enough to resist some damage from external forces.
This is perhaps the most important part of the entire compression assembly. Gauge is a display face that shows the pressure readings from the compression chamber.
A faulty gauge is unusable, and it should, therefore, be large enough for easy legibility and most importantly, be accurate.
Moving parts can inadvertently break down during use. Although you will be buying a quality compression tester, do ensure that the manufacturer gives you comprehensive warranty coverage.
This only serves to show that the product sold is of high quality and the manufacturer is positive about it. The advantage of a warranty is that the broken parts can be repaired without charges should you mess up or it breaks in your hands.
Our Final Verdict
So there you are, a breakdown of the five best compression testers you can find for your diesel engine. The problem with compression kits is that there are so many that you may not know where to begin.
For optimal performance, find a tester that is made of quality materials and is accurate. If you have more than one vehicle or you might want to use it with another vehicle, then having multiple adapters is always a plus.
If selecting one is too much for you, all the five above are solid options that will evaluate and help give your engine a clean bill of health.
Please let us know which of the five testers you opted for. Share any good or bad experiences you might have had as well.