How2 - Change the Timing / Cam Belt on a C18NZ Engine

[Robsey]

This is a How 2 for changing the Cam Belt on the C18NZ Engine, although the C16NZ, C16NZ2 and later C20NE are the same.

Step 1
Remove the air-filter housing - it is held in place by three 10mm (M6 thread) nuts. See the arrows for their locations.

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Step 2
Loosen the wheel nuts, whilst the car is still on the ground
It is not safe to swing on a nut wrench when the car is raised off the ground. I use a 17mm Socket on a strong-arm / breaker bar for better leverage.

Step 3
Jack up the car, and support on an Axle stand...I tend to put my stand under the sub-frame to which the wishbone attaches

Step 4
Undo wheel nuts and remove road wheel...As an extra point of safety, I always place the removed wheel under the sill of the car.
(On the side upon which you are working).

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Step 5
Remove the access panel from the splash shield in the driver's side wheel arch. This is held in place by one plastic expanding clip, and two No.2 Philips cross head self tapping screws.

This now gives access to the Crank-shaft pulley area.

[Robsey]

Step 6
Remove the Multi-V alternator drive belt, using a 15mm spanner on the bolt head arrowed. (red arrow)
A good tip given to me, is to link a 13mm spanner (looped end) onto the jaw of the open end of the 15mm spanner.
This gives more leverage against the sprung tensioner, and also reduces the chances of skinning your knuckles.

Turn the tensioner bolt clock-wise to remove the tension of the Multi-V belt.
Once the tension has been removed, slip the belt off the alternator pulley.

MAKE A NOTE OF THE ROUTE OF THE MULTI-V BELT, BECAUSE IT IS A VERY PECULIAR ROUTE.

Step 7
Undo the four E10 (Male spline / torx) Headed bolts to allow removal of the crank-shaft pully from it's sprocket.

Step 8
Undo the spline / Torx bolts from the Cam Belt cover.
There are three in the upper area, and two more low down near the crank-shaft sprocket. - yellow arrows.

[Robsey]

Step 9
Set the Cam-belt to its Setting Position.

The Camshaft has a line punched into it, which should point vertically upward towards a V notch in the rear plastic guard behind the cam-shaft sprocket - arrowed.

The Crank-shaft has an upside down U shaped indent in it...when set correctly, it will point right down towards another U mark near the oil sump flange - arrowed.

NOTE - The camshaft turns twice, for each turn of the crank shaft.
If the camshaft mark is pointing down, then you will need to turn the CRANK twice for one turn of the CAM-shaft.

TIP !!
It is easier to turn the crank-shaft, if the spark plugs have been removed from their plug-holes

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Step 10

Loosen the Cambelt tension by loosening the 13mm (M8) hex head bolt...then using an Allen Key, turn the tension plate anti-clockwise to looosen the belt tension. See the red arrows in the photo for step 8

RECOMMENDATION.

If you do not know the history of the engine...
It is recommended that the Cam Belt Tensioner and the water pump should be replaced for new items, when replacing the Cam Belt.

These items will add more expense to the job, but £50 for a complete Cam Belt Kit with tensioning roller and £30 for a water pump is much cheaper than a damaged engine.
Refer to the Haynes manual for the best positioning of the water-pump...Fixed by 3 Cap Head Allen Bolts - M8 thread.

ALTERNATIVELY - If you know the history, then the pump and tensioner could be swapped on every 2nd belt change.
My rule of thumb is...
New belt every 32 thousand miles.
New belt, pump, and tensioner every 64 thousand miles.

REBUILDING.
Step 11

If you are keeping the same tensioner, the you only need to loosen the 13mm bolt.
If you are fitting a new tensioner, then fit it loosely at this stage.

Step 12

Without moving the crank-shaft and the Cam-shaft sprockets, lay the new cambelt over the sprockets as shown in the photos.

Ensure that you keep the belt quite tight on the longest run (The right side - towards the front of the engine) between the Cam-shaft and Crank-shaft sprockets.
It is important to get this right, as poor running and economy will result if the belt is only one or two teeth out.

Step 13

Using the allen key again, you can now tension up the belt.
On the tensioner, you will see a line stamped into the plate and another line at the base of a V groove.
For a NEW belt, you will need to set the tensioner so that the pointer lines up with the right-hand line (with V groove) as shown by the Red Arrow.

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If you are just refitting the same belt, then you line up the pointer with the left hand line - yellow arrow.

Whilst holding this position, tighten up the 13mm bolt, to secure the tensioner in it's location.

Step 14 - Checking the belt.

Now, you will need to turn the crankshaft twice (clockwise).
Then re-line up the sprocket markers.

If the marks line up then great.

If not, then you will need to loosen the tensioner, and try re-fitting the cam-belt...
Repeat this stage until you are satisfied that the marks are lined up.

Step 15.

It is now a matter of ensuring that the water-pump and tensioner bolts are tight, then start to refit all the covers etc in this order.

a) Refit Plastic Cam-Belt Cover, and tighten up torx-head screws.

b) Refit Crank-shaft Pulley...note that the four holes are slightly off-set, and so the pulley only fits in one direction.

c) Refit Alternator Drive belt

d) Refit access panel

e) Refit the road-wheel, but only fit the bolts a little more than hand-tight. Lower the car to the ground, and tighten up wheel nuts to specified torque.

EXTRA POINT.

If your Alternator drive belt is quite heavily cracked...like the one in the sequence, then it is advisable to change this aswell.

Haynes will not tell you this, but the alternator drive belt passes through an engine mount, and so this will need to be split to allow removal of the belt. Yellow arrow in the photo for step 6 shows it's location.
You will need to support the weight of the engine, before splitting the mounting.

[Envoy CDX]

Very informative Robsey, PM me if this complete and I will lock the thread