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Product Selection by Problem Solving

Low or unequal compression in cylinders

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:

  1. Piston ring sticking, carbon deposits on the walls of the combustion chamber and on the piston top.

  2. Damaged cylinders' operating surface, or worn-out piston rings

  3. Improper adjustment of valves, or damage to the hydraulic lifters.

  4. Worn-out bushing guides, Valve Stem deformation.

  5. Burned valves or cylinder head gasket. Crack in the cylinder head, half or fully burned piston, destroyed piston rings.



  • If piston rings are coked or there are carbon deposits on combustion chamber wall - we recommend using Verylube Anticarbon fluid. Simply, you would need to spray it into engine cylinders through spark plug holes (for gasoline engines) or injector nozzles and glow plugs (for diesel engines) BEFORE CHANGING OIL.
    In order to prevent carbon build-up on piston rings and to effectively remove carbon deposits on inner surfaces of cylinders and valves - it is recommended to clean the engine oil system before each oil change by using XADO Atomex Total Flush – intensive oil system cleaner with Anti-Carbon Effect.


  • If there is minor damage to cylinder surface or if piston rings are not extremely worn-out - use XADO Revitalizant® EX120 for engine (Gasoline / Diesel) . You can apply Revitalizant® through spark plug holes (for gasoline engines) or injector nozzles and glow plugs (for diesel engines).
    If cylinders are heavily worn-out- use XADO Revitalizant® and make an oil change - use  XADO treatment to revitalize your engine (for gasoline engine or for diesel engine)


  • If low or unequal compression in cylinders resulted from improper valves configuration, or if hydraulic lifters are damaged, it is necessary to adjust the valves and replace worn or damaged hydraulic lifters.

  • If bushing guides or valve stem got deformed - it is recommended to repair the cylinder head, repair valve bushings, or replace damaged valves.

  • If valves or cylinder head gasket are burned or there is a crack in the cylinder head - complete overhaul of the engine need to be done.

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