5.7. Tightening Cylinder Head Bolts 1) Retightening cylinder head bolts on new engines by authorized specialist personnel (engine cold or warm) The cylinder heads are mounted with cylinder head bolts which are tightened by Intake side injector the angle-of-rotation method. On new engines the cylinder head bolts are 1 4 tightened up for the first time at the factory after the engine has been broken in. After the first 400 hours of operation 3 2 retighten cylinder head bolts 1 to 4 in the order shown in right figure by a further 90 ° Exhaust side EA6O6009 (1/4 revolution). The two outer screws (intake and exhaust sides) must not be retightened. NOTE :
The cylinder head bolts to be retightened must not be loosened first, but simply tightened by a further 90 ° (1/4 revolution) from their actual position. 2) Tightening cylinder head bolts after a repair by authorized specialist personnel (engine cold) Before inserting the cylinder head bolts oil Intake side injector them with engine oil on the thread (not to the bore) and coat the contact face of the 6 bolt head with “Optimoly White T” 1 4 assembly paste. Do not use any oils or oil additives that contain MoS 2 . The bolts must be tightened by the angle- of-rotation method as shown in right 3 5 2 figure.
Exhaust side EA6O6010 z 1st pretightening step = to 10 N m z 2nd pretightening step = to 80 N m z 3rd pretightening step = to 150 N m z 4th pretightening step = turn by 90 ° z Final tightening = turn by 90 ° Maintenance of Major Components - 145 -