Sealey VS5125 Instructions Manual page 6

5.2.11. Compress the oil pump drive chain tensioner and retain in
position using VS5125-07 Chain Tensioner Locking Pin.
5.2.12. Remove the oil pump drive chain tensioner and detach the
pump drive chain from the crankshaft sprocket.
© Jack Sealey Limited
5.2.13. Check for elongation of the timing chain. If the timing chain
has maximum permitted elongation then it MUST be
replaced.
5.2.14. Lift the retaining clip and non-return block of the timing chain
tensioner. Fully compress the tensioner plunger and retain in
position using VS5125-07 Chain Tensioner Locking Pin.
NOTE: When the timing chain tensioner is compressed and
chain tension is relieved, the inlet camshaft may rotate in the
direction of engine rotation due to valve spring pressure.
Original Language Version
VS5125 Issue: 3 - 22/03/17