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Home >> Ford >> 2000 >> Excursion 7.3 F, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1219 (Engine System - General Information) >> Diagnostic Tests >> Engine >> Compression Test - Compression Gauge Check >> Compression Test - Interpreting Compression Readings
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Compression Test - Interpreting Compression Readings

WARNING: This page is about a different car, the 2008 Ford RV Cutaway, 2008 Ford Econoline, 2008 Ford E450 Super Duty, and 2008 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
  1. If compression improves considerably, piston rings are faulty.
  2. If compression does not improve, valves are sticking or seating incorrectly.
  3. If 2 adjacent cylinders indicate low compression pressures and squirting oil on each piston does not increase compression (GASOLINE ENGINES ONLY), the head gasket may be leaking between cylinders. Engine oil or coolant in cylinders could result from this condition.

    Use the Compression Pressure Limit Chart when checking cylinder compression so that the lowest reading is within 75% of the highest reading.

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