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Poor or uneven compression in the cylinders

Signs of compression reduction:

  • Difficult starting of the engine
  • Rough engine running
  • One or more cylinders are not working
  • Popping in inlet or outlet area
  • Increased fuel consumption
  • Increase in pressure in the cooling system

Causes of low or uneven compression:

  1. Coking of the piston rings, coking deposits on the combustion chamber walls and on the piston crown.
  2. Wear or damage of the cylinder surface, non-critical wear of the compression piston rings.
  3. Incorrect valve adjustment, wear or damage to hydro-compensators.
  4. Valve guide wear, bent valves.
  5. Burnout of the valve and cylinder head gasket, crack in the cylinder head, the exhaust manifold of the cylinder head, burnout or partial destruction of the piston, destruction of the piston rings.


  1. In the case of coking on the piston rings and coking deposits on the combustion chamber walls and the piston crown, it is recommended to decarbonize them.

  2. Decarbonization is achieved through STEAL AtomEx Total Flush achieved. The product will be approx. Filled into the motor oil 150-200 km before the oil change and later drained completely with the used oil.

  3. If there is a loss of compression due to wear or We recommend this in the event of damage to the cylinder surface and non-critical wear of the piston rings STEAL 1 Maximum Stage which can rebuild worn metal surfaces by forming a metal-ceramic surface layer. In the event of significant cylinder wear, we recommend an additional treatment with XADO Gel-Revitalizant® for cylinders and, after the planned oil change, a full oil system treatment with an XADO Gel-Revitalizant® appropriate to the engine type (for Petrol- and diesel engines); XADO Revitalizant® EX 120
  4. In the event of low or unequal compression due to incorrect valve adjustment, wear or damage to the hydro-compensators, it is necessary to adjust valves and replace worn or damaged hydro-compensators.
  5. With wear of the valve guides, bending of the valve body, it is recommended to repair the cylinder head, change and grind valve liners, change damaged valves.
  6. In the event of a valve and cylinder head gasket burnout, a crack in the cylinder head, the manifold on the cylinder head, a burnout or partial destruction of the piston, it is necessary to carry out a full repair and replace the destroyed or deformed components.
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