Some erroneous operation and maintenance, resulting in premature engine failure. A new or overhauled engine after the engine is not running-new car or engine overhaul replacement cylinder liners, pistons, piston rings and bearings and other parts, but has not been fully run-in with a load of work, resulting in the early part of the wear and tear, and some also appeared pull-cylinder, bush-burning phenomenon. For example, a jacket with TY220 bulldozer NT855 engine, no overhaul as required after running directly with load operations, work less than 10h appeared bush-burning phenomenon. After two high-speed operation of the engine immediately after a cold start the engine cold start in the cold due to the state, the oil viscosity is high, the flow resistance is also large, so that oil into the friction of the time lag, the various parts of the engine has not been fully lubricated, Chongqing Li excavator repairs caused Adverse damaged engine lubricating gears and bearings, but also exacerbated the cylinder and bearing wear. Especially supercharged engine will cause the turbocharger shaft ablation. Only improve this reason, after a supercharged engine will start to be idle, standby oil temperature rises, liquidity improved sufficiently lubricated turbocharger speed, which is even more important during the cold winter months. For example, a station imports from Russia T-330 bulldozer, engine B-400 engine (V-shaped 8-cylinder with two turbochargers, power 300kw). This is precisely when bulldozers removed from the car carrying the winter season, after starting the engine speed machine hand to open the site, the engine can be found idling times, but along the load on the turn did not move. The original turbocharger shaft ablation due to poor lubrication, the cylinder intake air be reduced, a significant decline in engine power. 3 engine suddenly stalled when the supercharged engine suddenly stalled at high speeds, oil pump stops immediately, within the turbocharger oil stopped flowing. If the temperature of the exhaust manifold is high at this time, the heat will be absorbed into the booster housing, the oil will stay there baked coke, oil inlet blocked, leading to starvation sleeve, 1 may be air filter blocked. 2 may be blocking the air inlet, and a lot of debris digging machines are convenient bags such as toilet paper inlet inhalation. 3 motor ripped out, plugged in, open fan, a stalls test, the speed did not change is that the majority of the variable resistor is broken. Doosan excavator DH60 air conditioning out how to do a small amount? First, when a tune windshield, wind and small wind has not changed? 2 If no change is always the small wind that control different amount of wind resistance on the blower relay out of the question. 3 If the wind changes, but the biggest wind is still very small, you can put air conditioning filters (Dust) removed to try. 4 If the wind right on the big, gray is too much, lookout blocked, another air conditioning filters on the line. 5 Note that the filter must be, otherwise temporarily removed after the wind, the air conditioning inside after a period of time is all gray, than clean the filter to be more difficult.