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hi


You are replying to:
VMS
Posted 3/20/2013 8:05 PM (#628658 - in reply to #628594)
Subject: Re: Low Compression





Posts: 3486


Location: Elk River, Minnesota
Hiya,

If you take the motor to a service shop, have them perform a leak-down test on the cylinders. This will determine if the problem goes beyond being bad rings on the piston, as they can determine if the cylinder itself is shot, a head gasket is bad or the head is warped. In all three of these situations, the leak down test can determine if the leak is external or internal, whereas a compression test usually determines only if rings are bad.

A quick test with compression is to squirt some oil in the cylinder and then re-do the compression test. If the compression stays high with very slow leaking, it is probably in need of new rings. But...this only works if the head is not leaking.

The leak down test will determine where the leak is happening as the cylinder is maintained under pressure, and external leaks are found by spraying soapy water or windex around the head (bolts, gasket, etc.) If the leak is external, it will show in the form of bubbles. If it is internal, you can literally hear the air moving by. If the latter of the two happens, it's rebuild time. With the Age of the motor, though, the cost of a rebuild may not be worth it as it could cost more than the motor is worth... It may be less than a replacement, though, and a good rebuild will have that motor running for years to come.

Steve

Edited by VMS 3/20/2013 8:07 PM

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