To start with, I want to say, almost all of the bigger suppliers of used equipment are no crooks. But as the Germans say: “The Exception confirms the Secret. ” And what is better than hoping an engine is good? That is better to learn it.
When you arrive on-site and you go to inspect a wheel termes conseillés, excavator, bulldozer or any other used construction machine with a combustion engine, we recommend this treatment: Komatsu WA500-1 Wheel Loader manual
Before turning the important thing have a look if the engine is cold. In the event it is heated up already this may be a sign of starting problems with a cool engine (compression).
Check the oil condition. New olive oil along with old air- and fuel filters and no other service done is a bad indication.
Now open the chillier reservoir and have a look to coolant quality. There really should not be plain drinking water in and the coolant should be a little more or less clear. It will not stink for diesel and should not contain oil.
Maintain the cooler reservoir open up and start engine. Enjoy the smoke on start. A little grey or dark-colored smoke should disappear after max. 30sec.
Watch into the cooler reservoir or put your odds on the opening. There really need to be no pressure. Now you can close it.
Now it is time to examine the so called Blow-By. When an engine is running a certain amount of pressure from the combustion is bypassing pistons and cilindro rings and finds their way to the crankshaft case. Therefore an vent out line is existing and accessible with almost all of the engines. (With some modern engines this hose leads back to the air inlet channel to returning the gas to the engine. )
To check the Blow-By open the oil filler cap and put your hand on. It is hard to describe the level of allowed Blow-By. However, to give you a sense: Blow through your nostril at your hand. In the event that the level of engine wear is normal it should be less than that. Engine must run in idle! The olive oil filler cap should not be covered with grey residues. This would be an indication of watering the engine oil.
Now you can perform other machine tests like a Stall-Test or Cycle Time Check. This will warm up the engine to functioning temperature. Run the engine in working speed and watch the smoke. A bit black smoke can be regular under weight. More black smoke occurs when the fuel is not combusted completely. Black smoke indicates that the fuel gets mixed up with oil somewhere before burning. Unburned fuel which gets to the exhaust stream is in charge of white smoke cigars.