Ford Escape Quiz
Powertrain

General Procedures - Cylinder Compression and Leakage Test

In this manual: Powertrain
General Information — 26Chassis — 160Powertrain — 323Electrical — 356Body and Paint — 290
15steps
~90min
4/5difficulty
Done 0 of 15
  1. Make sure the engine oil is of the correct viscosity and at the correct level, and that the battery is fully charged. Operate the vehicle until the engine reaches normal operating temperature. Turn the ignition key to the OFF position.
  2. Remove the spark plugs.
    For additional information, refer to: Spark Plugs (303-07A Ignition System - 1.5 L EcoBoost (132 kW/180 L PS) - I3 (Y1), Removal and Installation).
    For additional information, refer to: Spark Plugs (303-07B Ignition System - 2 L EcoBoost (177 kW/240 L PS) - MI4, Removal and Installation).
    For additional information, refer to: Spark Plugs (303-07C Engine Ignition, Removal and Installation).
  3. Set the throttle valves to the fully open position.
  4. Install the compression gauge in cylinder No. 1.
  5. Install the auxiliary starter switch in the starting circuit. With the ignition switch in the OFF position and using the auxiliary starter switch, crank the engine for a minimum of 5 compression strokes and record the maximum reading. Note the approximate number of compression strokes required to obtain the highest reading.
  6. Repeat the test on each cylinder, cranking the engine for approximately the same number of compression strokes.

Compression Test - Test Results

  1. Compression pressures are considered within specification if the cylinder with the lowest reading is at least 75% of the highest reading.

Compression Pressure Limit Values Table

  1. Refer to the Compression Pressure Limit Values Table.
    Maximum Cylinder Pressure - Minimum Cylinder Pressure Maximum Cylinder Pressure - Minimum Cylinder Pressure Maximum Cylinder Pressure - Minimum Cylinder Pressure Maximum Cylinder Pressure - Minimum Cylinder Pressure
    134.0 - 100.9 psi (924 - 696 kPa) 164.0 - 123.0 psi (1131 - 848 kPa) 194.1 - 145.0 psi (1338 - 1000 kPa) 223.9 - 168.0 psi (1544 - 1158 kPa)
    136.0 - 102.0 psi (938 - 703 kPa) 166.1 - 124.0 psi (1145 - 855 kPa) 195.9 - 147.1 psi (1351 - 1014 kPa) 226.0 - 169.0 psi (1558 - 1165 kPa)
    138.1 - 104.0 psi (952 - 717 kPa) 168.0 - 126.0 psi (1158 - 869 kPa) 198.0 - 147.9 psi (1365 - 1020 kPa) 228.0 - 171.0 psi (1572 - 1179 kPa)
    140.0 - 105.0 psi (965 - 724 kPa) 170.0 - 127.1 psi (1172 - 876 kPa) 200.0 - 150.0 psi (1379 - 1034 kPa) 230.0 - 172.0 psi (1586 - 1186 kPa)
    142.0 - 107.0 psi (979 - 738 kPa) 172.0 - 128.9 psi (1186 - 889 kPa) 201.9 - 151.0 psi (1392 - 1041 kPa) 232.1 - 174.0 psi (1600 - 1200 kPa)
    143.9 - 108.1 psi (992 - 745 kPa) 174.0 - 131.0 psi (1200 - 903 kPa) 204.1 - 153.0 psi (1407 - 1055 kPa) 233.9 - 175.1 psi (1613 - 1207 kPa)
    146.1 - 109.9 psi (1007 - 758 kPa) 176.1 - 132.0 psi (1214 - 910 kPa) 206.0 - 154.0 psi (1420 - 1062 kPa) 236.0 - 176.9 psi (1627 - 1220 kPa)
    147.9 - 111.0 psi (1020 - 765 kPa) 178.0 - 133.0 psi (1227 - 917 kPa) 208.0 - 155.9 psi (1434 - 1075 kPa) 238.0 - 178.0 psi (1641 - 1227 kPa)
    150.0 - 113.0 psi (1034 - 779 kPa) 180.0 - 135.0 psi (1241 - 931 kPa) 210.0 - 157.1 psi (1448 - 1083 kPa) 240.0 - 180.0 psi (1655 - 1241 kPa)
    152.0 - 114.0 psi (1048 - 786 kPa) 182.0 - 135.8 psi (1255 - 936 kPa) 212.0 - 157.9 psi (1462 - 1089 kPa) 242.1 - 181.0 psi (1669 - 1248 kPa)
    154.0 - 115.0 psi (1062 - 793 kPa) 184.1 - 138.1 psi (1269 - 952 kPa) 214.1 - 160.0 psi (1476 - 1103 kPa) 244.0 - 183.0 psi (1682 - 1262 kPa)
    156.1 - 117.0 psi (1076 - 807 kPa) 185.9 - 140.0 psi (1282 - 965 kPa) 216.0 - 162.0 psi (1489 - 1117 kPa) 246.0 - 184.1 psi (1696 - 1269 kPa)
    157.9 - 118.1 psi (1089 - 814 kPa) 188.0 - 141.0 psi (1296 - 972 kPa) 218.0 - 163.0 psi (1503 - 1124 kPa) 248.0 - 174.3 psi (1710 - 1202 kPa)
    160.0 - 119.9 psi (1103 - 827 kPa) 190.0 - 142.0 psi (1310 - 979 kPa) 220.0 –165.1 psi (1517 –1138 kPa) 250.0 –187.0 psi (1724 –1289 kPa)
    161.0 –121.0 psi (1110 –834 kPa) 192.0 –144.0 psi (1324 –993 kPa) 236.6 –166.1 psi (1631 –1145 kPa) 251.9 –189.0 psi (1737 –1303 kPa)

Compression Test - Compression Test Interpretation

  1. If one or more cylinders shows low compression, add approximately one tablespoon of Ford-specification engine oil through the spark plug hole into the low-compression cylinders. Repeat the compression test on those cylinders.
  2. If compression improves significantly, the piston rings are worn or damaged.
  3. If compression does not improve, the valves are sticking or not seating correctly.
  4. If 2 adjacent cylinders show low compression and compression does not increase when oil is added to each piston, the cylinder head gasket between the cylinders may be leaking. Engine oil or coolant in the cylinders may result from this condition. Use the Compression Pressure Limits table. If the lowest cylinder value is within 75% of the highest value, the test is acceptable.

Cylinder Leakage Test

  1. When a cylinder shows low compression, use the Cylinder Leakage Tester to help determine the exact cause.
  2. Insert the leakage tester into the spark plug hole, position the piston at TDC on the compression stroke, and admit compressed air.
  3. When the combustion chamber is pressurized, the tester gauge shows the percentage of leakage. Leakage greater than 20% is excessive.
  4. While air pressure is maintained in the cylinder, listen for escaping air. A leak in the intake valve can be heard at the throttle body. A leak in the exhaust valve can be heard at the exhaust pipe. A leak past the piston rings can be heard at the crankcase breather (PCV). If air passes through the cylinder head gasket into an adjacent cylinder, the noise will be evident at the spark plug hole of that adjacent cylinder. Cracks in the cylinder block or a leaking head gasket into the cooling system can be detected by a stream of bubbles in the radiator.
  5. Install the spark plugs.
    For additional information, refer to: Spark Plugs (Engine Ignition 303-07A — 1.5 L EcoBoost (132 kW/180 L hp) — I3 (Y1), Removal and Installation).
    For additional information, refer to: Spark Plugs (Engine 303-07B, Ignition — 2 L EcoBoost (177 kW/240 L hp) — MI4, Removal and Installation).
    For additional information, refer to: Spark Plugs (303-07C, Engine Ignition, Removal and Installation).

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