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Home >> Ford >> 2001 >> Excursion 7.3 F, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 2152 (Engine System - General Information) >> Diagnosis And Testing >> Engine >> Compression Test - All Vehicles Except Hybrid >> Compression Test - Interpreting Compression Readings
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Compression Test - Interpreting Compression Readings

WARNING: This page is about a different car, the 2010 Mercury Milan, 2010 Lincoln MKZ, and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
  1. If compression improves considerably, piston rings are worn or damaged.
  2. If compression does not improve, valves are sticking or not seating correctly.
  3. If 2 adjacent cylinders indicate low compression pressures and squirting oil on each piston does not increase compression, the head gasket may be leaking between cylinders. Engine oil or coolant in cylinders could result from this condition. Use the COMPRESSION PRESSURE LIMIT TABLE  when checking cylinder compression so that the lowest reading is within 75% of the highest reading.
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