2007 – 2014 Nissan X- Trail
All Head Services have had numerous occurrences of broken camshafts on the Nissan QR25DE engines. The camshafts have to be removed to access the cylinder head bolts. These breakages are caused by customers when they are either removing or refitting the camshafts.
The correct procedure MUST be followed when removing and fitting the camshafts, as failure to do this WILL cause the camshaft to break. If the correct procedure is not followed the camshaft can lift up on an angle and bind in the thrust area. The leverage from the valve spring will then cause the camshaft to snap!
This creates the inconvenience of having to source and fit another camshaft and line bore the cam journals again, which adds additional cost due to rework.
To Loosen the Camshaft:
Loosen all bolts in the reverse order to the sequence to the diagram below (refer to full VACC Article) in several steps.
To refit the Camshafts:
Apply sealant to the outer edge of the front bearing cap.
Make sure that the bearing caps with the numbers 2 to 5 are fitted in order on the intake camshaft, and the bearing caps with letters A to D, are fitted in order on the exhaust camshaft. They must be able to be read from the exhaust side of the engine.
Tighten the camshaft bearing cap bolts in four steps, following the sequence in the diagram below.
1st: Bolts 9 to 11 on the front bearing cap to 2 Nm.
2nd: Bolts 1 to 8 to 2 Nm.
3rd: Tighten all bolts in order to 5.9 Nm.
4th: Tighten all bolts in order to 10.4 Nm.
Make sure to wipe off any excess sealant from the front bearing cap.