| Testinf the combustion chamber for tightness |
| Special tools and workshop equipment required |
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| Pressure hose -MP1-210 (VW 653/3)- (replace gasket ring with a spark plug gasket ring) |
Note | Observe safety measures and rules for cleanliness when working on vehicles with liquefied petroleum gas system (LPG) → Chapter. |
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| Unscrew the spark plugs. |
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| Position piston of the relevant cylinder to dead centre. |
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| Screw the pressure hose MP 1-210 into the spark plug thread. |
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| Connect pressure hose to compressed air. |
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| With the assistance of a second mechanic, lock the screw at the crankshaft on TDC position in order to avoid the displacement of the piston after pressure build-up. |
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| Build up a pressure of approx. 0.3 MPa (3 bar) in the combustion chamber. |
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| Determine how the pressure escapes: |
| 1 - | Via the inlet valve(s) - the pressure enters the throttle valve. |
| 2 - | Via the outlet valve(s) - the pressure enters the exhaust system. |
| 3 - | Via the piston rings – pressure enters the engine block. |
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