whats the odo meter reading ? how many owners before this owner is selling the car.
people use 'Great Deception Tools' in case of diesel engines, so if there is some maintenance history available its easy. compression test, injector pump condition & blow by
To perform a compression test on a diesel engine, you need to have a diesel compression gauge and a glow plug or injector adapter. Remove all the glow plugs to check any cylinder. Crank the engine at least five revolutions and the same number of revolutions for each cylinder. It would probably be a good idea to have a battery charger hooked up during the test. You will need to check 2C engine manual to determine the minimum compression values that are acceptable...but if any cylinder is 10% lower than the others it is a good indication that this engine is probably due for some major work soon.
Doing a leak down test, particularly in conjunction with a compression test will give you a great deal of additional information and allows problems to be pinpointed. The condition of the engine is determined by measuring the degree to which a cylinder with valves closed leaks air. In simplified terms, if air is pumped into the cylinder at 100 PSI and the gauge reads 97 PSI, then the leak down percentage is 3%. Doing a leak down test is a fairly simple matter.
A cylinder leakage test is done with the engine at normal temperature, not running, and the piston at Top Dead Center on the compression stroke. During this test, compressed air is pumped into the cylinder, and a cylinder leakage gauge gives a reading of air leaking out of the cylinder in percent. Listen for escaping air at the oil fill cap, the exhaust pipe, the intake manifold, and the cooling system, [for safety , let the system cool first]. This helps pinpoint the problem area. Total cylinder leakage should be no more than 25 percent; leakage from the cylinder head and valves should not exceed 10 percent; leakage from pistons and piston rings should not exceed 20 percent.
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