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Engine Compression Test Demonstrated After 280,000 Miles

Here is a demo video of how an engine compression test is done with some actual engine compression numbers from a used vehicle engine after logging in 280,000 miles.

Engine Compression Testing

A compression test is a basic car maintenance/repair procedure where the engine is made to spin through its cycles momentarily while a compression gauge is fitted into a single spark plug hole as each cylinder is being tested. As the engine spins, the compression gauge will measure the maximum pressure within the cylinder tested.

The significance of this measure is that the cylinder’s compression value is dependent upon the engine's valves, its valve seats, piston rings; and, whether these parts are wearing evenly. If any of these components are loose, leaky, open or burned, compression is lost and performance suffers significantly. A compression test can also help you determine whether there is a leak in your cylinder head gasket as well as avoid a head gasket scam by a mechanic or service center technician.

Roughly, a healthy cylinder reading should show compression over 100 psi per cylinder, with no more than 10 percent variation between the highest and lowest readings amongst the remaining cylinders tested. If the readings are relatively low in reference to the specs on the engine of your particular car; or worse yet, show too much variation between cylinders, then you can expect that an engine rebuild is in your car’s near future.

Related articles: What a Used Toyota Engine Rebuild Can Cost and Ford Mechanic Catches Engine Rebuild Scam.

The importance being able to do a compression test of an engine is to help figure out the health and thereby a vehicle’s true worth when considering on buying a particular used car. In fact, in most cases it is so simple to do that it is a recommended skill to add to your vehicle inspection checklist.

For a more in-depth discussion of the importance of a compression test and how to do it, refer to this article “The Most Important Used Car Test You Should Do Before Deciding to Buy a Used Car” for some additional information that can help you with your car.

The Health of a 1996 Toyota 4Runner After 280,000 Miles

As an example of just how useful a cylinder compression test can be and a testament to how well a Toyota engine can perform even after 280,000 miles, here is a recent Toyota Maintenance YouTube channel video that reveals what kind of compression test numbers are possible when a vehicle is well maintained.

Toyota Engine 5VZ-FE with 280,000 miles compression test

And finally…

For additional articles related to engine health and compression testing, here are two selected articles that will help you make use of today’s information: “Avoid Getting Scammed with This Blown Head Gasket Tutorial for Non-Mechanics” and “Blown Head Gasket Scam Tutorial for Non-Mechanics Part 2.”

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Timothy Boyer is a Torque News automotive reporter based in Cincinnati. Experienced with early car restorations, he regularly restores older vehicles with engine modifications for improved performance. Follow Tim on Twitter at @TimBoyerWrites for daily new and used vehicle news.

Image Source: Photo by Anna Shvets from Pexels