Execution sequence
1. Check the oil level in the engine oil pan (see «Checking the levels of technical fluids»). We make sure that there is no emulsion in the engine oil pan (oil on the level indicator should be free of white streaks). The appearance of an emulsion indicates damage to the cylinder head or its gasket (see «Cylinder head - gasket replacement»).
2. We make sure that there are no oil stains in the expansion tank of the cooling system, as well as that there is no seething in the expansion tank under various engine operating modes. In the presence of these phenomena, damage to the cylinder head or its gasket is possible (see «Cylinder head - gasket replacement»).
3. We check the absence of oil leaks from under the oil filter, from under the drain plug of the oil pan, from the front and rear crankshaft oil seals, camshaft oil seals (with the front timing belt cover removed, see «Timing belt - condition check, tension adjustment and replacement»), head cover gaskets (with a leaky cylinder head gasket, oil usually accumulates in candle wells) and engine sump. If oil leaks are found, damaged elements must be replaced (see relevant sections).
4. We check the absence of breaks in the rubber-metal hinges of the left and right supports of the power unit, as well as the lower rod. Damaged parts must be replaced (see «Supports and rods of the power unit - replacement»).
5. We check the absence of noise and knocks in the engine. For the most accurate diagnosis, you must use a technical stethoscope:
1) knocking of the crankshaft of a dull metallic tone, the frequency of which increases with the speed of the engine crankshaft;
2) knock of connecting rod bearings; audible at idle speed of the engine with a sharp opening of the throttle.
3) the sound of pistons is unvoiced, muffled; audible at a low frequency of the crankshaft under load;
(To eliminate the above listed knocks, disassembly and troubleshooting of the engine block is required. It is better to entrust this work to a specialized service.)
4) knocking inlet and outlet valves of high tone at regular intervals; sounds good when the engine is idling. Its frequency is less than the frequency of any other knock in the engine (see above). Usually caused by malfunctioning valve lifters (see «Valve lifters - replacement»).
6. We check the absence of engine smoke in various operating modes.
Black smoke during regassing indicates a too rich working mixture. This is most likely caused by a malfunction in the engine management system (see «Engine management system - condition check»).
Blue smoke indicates that oil has entered the combustion chamber. If smoke occurs when releasing gas, at idle and when the engine is running at high speeds without load, but there is no smoke during uniform movement, the valve stem seals are most likely worn (see «Oil seals - replacement»). If the smoke increases with an increase in speed and load, and with a uniform movement behind the machine, a bluish plume stretches, most likely the reason is the wear of the oil scraper rings. To eliminate this malfunction, it is necessary to disassemble and repair the engine block. It is more expedient to entrust this work to a specialized service.
Thick white smoke indicates that coolant has entered the combustion chamber. This may be caused by a warped cylinder head (see «Cylinder head - check») or damage to the cylinder head gasket (see «Cylinder head - gasket replacement»).
7. Check the compression in the engine cylinders (see «Checking compression in the engine cylinders»).
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