Mazda CX-9 Engine Compression Test Cost

Know what price you should pay to get your vehicle fixed.

The average cost for a Mazda CX-9 engine compression test is between $188 and $239. Labor costs are estimated between $188 and $239. Estimate does not include taxes and fees.
Note about price: The cost of this service or repair can vary by location, your vehicle's make and model, and even your engine type. Related repairs may also be needed. Talk with a RepairPal Certified shop to learn which repairs might be right for you.

How does a Engine Compression Test work?

To generate power, an engine utilizes the exhaust gasses created in the combustion process as a source of power to move the pistons up and down inside the cylinders. The engine in a car is known as a "four-stroke" (or "four-cycle") engine that relies on four distinct piston strokes (intake, compression, power, exhaust) to complete one full operating cycle. During the compression and power strokes, the intake and exhaust valves are closed and the cylinder is sealed airtight.

What are the symptoms of a bad Engine Compression Test?

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Can I drive with a bad Engine Compression Test?

A vehicle that has an engine suffering from low compression can be a hazard to drive if it tends to stall at idle. This can make navigating busy intersections on the road a dangerous job. The vehicle should be evaluated as soon as possible if this is the case. Otherwise, the vehicle can be driven for short distances.

How often do Engine Compression Tests need replacement?

The main cause of low engine compression is premature wear of the piston rings that seal the pistons against the cylinder walls or damage to the valves. Poor lubrication may result in piston ring and valve failure. With normal vehicle maintenance - including regular oil changes - sufficient engine compression should be retained for the life of the vehicle.

How are Engine Compression Tests done?

To perform a compression test, a technician will make sure the oil level is normal and warm up the engine before disabling the ignition and fuel systems. The spark plug wires are disconnected and the spark plugs are removed. A compression tester is installed in one of the spark plug mounting holes. The technician will have someone turn the key to engage the starter for a short time. The gauge on the compression tester reveals the pressure in the cylinder. The technician will record the reading and repeat with the rest of the cylinders. The process is more complex for a test with the vehicle running, but it reveals more information about the condition of the engine.

RepairPal Recommendations for Engine Compression Test issues

Variations from one vehicle model to the next require access to vehicle-specific information and repair procedures. It is recommended that a qualified technician diagnose and repair symptoms of low compression.

What to look out for when dealing with Engine Compression Test issues

The ignition system and/or the fuel system need to be disabled prior to performing an engine compression test, unless the test is being done while the engine is running. In the latter case, a professional technician should perform the test. Damage or injury can occur if excess fuel is sprayed from the engine during the procedure.

Can I replace the Engine Compression Test myself?

While a basic engine compression test is not too difficult to perform on some vehicles, it is quite a challenge on others. Access to cylinders located at the back of the engine compartment can be minimal. Specific vehicle data must be referenced for comparison to the compression test results. Moreover, an engine compression test alone is usually not enough information to properly diagnose poor engine performance. Other tests need to be conducted for a solid and targeted diagnosis because several conditions can lead to the symptoms associated with compression loss. These tests are usually better left to a professional technician.