Windstar V6-232 3.8L (1995)
Compression Check: Testing and Inspection
Compression Test
Compression Gauge Check
1. Make sure oil in crankcase is of the correct viscosity and at proper level and battery is properly charged. Operate vehicle until engine is at
normal operating temperature. Turn ignition switch to the OFF position, then remove all spark plugs .
2. Set throttle plate in wide-open position.
3. Install a compression gauge such as Rotunda Compression Tester 059-00009 or equivalent in No. 1 cylinder.
4. Install auxiliary starter switch in starting circuit. With ignition switch OFF, and using auxiliary starter switch, crank engine at least five
compression strokes and record the highest reading. Note the approximate number of compression strokes required to obtain the highest
reading.
5. Repeat test on each cylinder, cranking the engine the same number of compression strokes.
Test Conclusion
The indicated compression pressures are considered within specification if the lowest reading cylinder is within 75 percent of the highest. Refer to
the following chart.
If one or more cylinders reads low, squirt approximately one tablespoon of XO-20W30-QR or equivalent engine oil meeting Ford specification
ESR-M2C179-A on top of the pistons in the low-reading cylinders. Repeat compression pressure check on these cylinders.
Interpreting Compression Readings
1. If compression improves considerably, piston rings are at fault.
2. If compression does not improve, valves are sticking or seating poorly.
3. If two adjacent cylinders indicate low compression pressures and squirting oil on pistons does not increase compression, the cause may be a
head gasket leak between cylinders. Engine oil and/or coolant in cylinders could result from this condition.
Check the compression pressure limit chart when checking cylinder compression.
