- the pressure in the engine lubrication system has dropped. The cause of this malfunction is often increased wear on the camshaft journals and camshaft bearing beds in the cylinder head. When the beds and their covers are worn out, the block head is replaced as an assembly, since the beds are made directly in its body;
- valve knock at normal clearances in the valve drive mechanism. Caused by increased wear of the camshaft cams due to the use of low-quality engine oil or damage to the oil filter.
You will need: the same tools as for removing the timing belt (cm. «Replacing the timing belt»), camshaft seals (cm. «Replacing camshaft seals»), as well as a TORX E11 key, a torque wrench.
1. Remove the solenoid valves of the VCT system by disconnecting the wiring harness blocks from them and unscrewing one bolt securing the VCT system caliper.
2. Remove the cylinder head cover (cm. «Replacing the cylinder head cover gasket»).
3. Remove the timing belt (cm. «Replacing the timing belt»).
4. Remove VCT mechanisms (cm. «Replacing camshaft seals»).
Pic. 5.14. Removal of camshafts: 1 – a head of the block of cylinders; 2 – support VCT; 3 – bolts of fastening of covers of bearings of camshafts; 4 – covers of bearings of camshafts; 5 - camshafts
5. Remove the VCT caliper (pos. 2 in fig. 5.14), having unscrewed four bolts of its fastening to a head of the block of cylinders.
NOTE: VCT caliper mounting bolts of different lengths: located further from the longitudinal axis of the block head - 38 mm, closer to the axis - 51 mm. Do not mix them up when reinstalling.
6. Turn out bolts 3 (see fig. 5.14) fastening of covers of 4 bearings of camshafts in an order, the return shown on fig. 5.15, and remove the camshafts.
Pic. 5.15. The order of tightening the bolts of the camshaft bearing caps
WARNING: Camshaft bearing caps are marked with serial numbers. Remember or write down the location of the covers in order to install them in their original places: the covers are processed together with the cylinder head and it is forbidden to depersonalize them.
7. Remove epiploons from necks of camshafts.
NOTE: Note
NOTE: Replace the camshaft seals with new ones each time they are removed.
8. Inspect the camshafts. The threads in the holes for mounting the VCT mechanism must not be damaged or worn. The surfaces of the bearing journals and cams must be well polished and without damage. On the working surfaces of the necks, scoring, nicks, scratches, aluminum enveloping from the bearing seats in the block head are not allowed. If there are signs of seizing, overheating, deep scratches or wear in the form of a cut on the working surfaces of the cams, replace the shafts.
WARNING: Grinding the camshaft cams to eliminate stepped wear is prohibited, since changing the size of the cam profile will disrupt the valve timing.
9. In workshops equipped with special tools and fixtures, you can check the radial runout of the camshaft journals. If the runout is greater than 0.02 mm or the journals are misaligned, replace the shaft as it cannot be straightened.
10. Lubricate the beds of the camshafts with clean engine oil and lay the camshafts in them in such a position that none of the cams rests on the shim of the valve lifter with the highest part of its toe.
Pic. 5.16. Places for applying sealant to the VCT caliper
11. Install the VCT caliper after applying sealant to its surfaces shown in fig. 5.16.
12. Establish covers of bearings of camshafts, tighten bolts of their fastening and bolts of fastening of support VCT in the order shown in fig. 5.15, in three steps:
- 1st step - Tighten the bolts evenly by half a turn each until the bearing caps and VCT caliper are in contact with the surfaces of the cylinder head;
- 2nd stage - tighten the bolts securing the camshaft bearing caps and VCT caliper to a torque of 7 Nm;
- 3rd stage - tighten the bolts of the camshaft bearing caps and VCT caliper by 45°.
13. Press the camshaft oil seals into the VCT caliper sockets (cm. «Replacing camshaft seals»).
14. Install the rest of the removed parts in the reverse order of removal.
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