Symptoms of compression decrease:
- Difficult engine start
- Unstable operation in all modes
- One or several cylinders do not function
- Popping sounds in the inlet and outlet manifold
- Increased fuel consumption
- Increased pressure in the cooling system connection
Reasons for low or unequal compression:
- Piston ring sticking, carbon deposits on the walls of the combustion chamber and on the piston top.
- Wear or damage to the operating surface of cylinders, non-critical wear of compression piston rings.
- Improper adjustment of valves, wear or damage to the hydraulic lifters.
- Wear of guide bushings, deformation of the valve stem.
- Burning-out of the valve or of the cylinder head gasket, through crack in the cylinder head, warpage of the cylinder head, complete burning-out or partial destruction of the piston, destruction of piston rings.
In case of sticking of piston rings and presence of significant carbon deposits on the walls of the combustion chamber and on the piston top it is recommended to decarbonize the cylinders at any operation stage by introducing Verylube Anticarbon into the cylinders through spark plug holes (for gasoline engines) or through orifices for nozzles or glow plugs (for diesel engines) without changing the motor oil. .
In order to prevent sticking of piston rings and to efficiently remove the carbon deposits on inner surfaces of cylinders and valves it is recommended to clean the oil system of any engine before each oil change by introducing XADO VitaFlush – intensive cleaner of oil system into the old oil and further engine operation within 180−500 miles of run before the oil change.
By wear or damage to the operating surface of cylinders, as well as by non-critical wear of compression piston rings the cylinders should be treated with XADO Revitalizant® for cylinders by introducing the Revitalizant® through plug holes (for gasoline engine) or through orifices for nozzles or glow plugs (for diesel engine).
If the cylinders are significantly worn, after treatment of cylinders with XADO Revitalizant for cylinders and the scheduled change of engine oil the whole oil system should be treated with a XADO Revitalizant® for a certain engine type (for gasoline engine or for diesel engine); XADO Revitalizant® EX120; XADO 1 Stage Revitalizant® or XADO АМС Maximum.
- In case of low or unequal compression resulting from improper adjustment of valves, wear or damage to the hydraulic lifters, it is necessary to adjust the valves and replace worn or damaged hydraulic lifters.
- By wear of guide bushings, deformation of the valve stem it is recommended to repair the cylinder head, repair and bore valve guides, replace damaged valves.
- By burning-out of the valve or of the cylinder head gasket, through crack in the cylinder head, warpage of the cylinder head, complete burning-out or partial destruction of the piston it is necessary to carry out a complete overhaul with replacement of destroyed or deformed parts.