M40 Timing Belt Change

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M40 Timing Belt Change (Originally Submitted on the E30 Zone by Gwynleym10 Please visit OverlandintheSun.com to see his charity drive from London to Cape Town)

Please note that this car had air - con so ignore the extra pipes / slightly bigger radiator + compressor.


Take the fan cowling off:

Image:M40timingbelt0.jpg


Drain the coolant off (into a container and dispose of responsibly!) Its useful to remove the top water pipe at this point as well:

Image:M40timingbelt1drain.jpg


Remove the reverse nut viscous cooling fan - it takes sudden movement rather than torque to undo it:

Image:M40timingbelt2removefan.jpg


Undo the bolts on the main pulley which is bolted onto the water pump:

Image:M40timingbelt3removepully.jpg


Undo the lower pulley using one socket to hold it in place and another to undo the bolts:

Image:M40timingbelt4removelowerpully.jpg


Take all the belts and pulley away and you are left with:

Image:M40timingbelt5waterpump.jpg


I now make sure that I can adjust my alternator (random way round I know).

Next remove the lower sensor with an allen key, one the bolt is out just twist it round back and forth until it is free:

Image:M40timingbelt6removesensor.jpg


Take the whole of the dizzy cap off leave the leads on:

Image:M40timingbelt7removedizzycapcover.jpg


Take the leads carefully off the spark plugs and set aside:

Image:M40timingbelt8removeleads.jpg


Now remove the thermostat housing (I think it is 3 10mm bolts which are NOT tight) once undone take the top hose off as well:

Image:M40timingbelt9removethermostatehousing.jpg


Undo the 3 allen bolts that hold the rotor on and remove the rest of the dizzy:

Image:M40timingbelt10removerotar.jpg


The next stage is to remove all of the bolts that hold the cover on - they should not be tight - be careful with them as the do go directly into the head / block. You will now see the whole of the timing belt:

Image:M40timingbelt11removecovers.jpg


Image:M40timingbelt12removecovers.jpg


Pile of bits...

Image:M40timingbelt13.jpg


Old belt:

Image:M40timingbelt13oldcambelt.jpg


Before removing the belt you need to set the timing use this tool... They only cost about £15-20:

Image:M40timingbelt14camtool.jpg


Undo the plug (it may have gone walkies) on the inlet side of your engine bell housing:

Image:M40timingbelt15flywheelplug.jpg


Put the long bit of the tool in the hole (ooh er) (gently does it):

Image:M40timingbelt16findingTDC.jpg


While holding the tool and pushing slightly on it - turn the engine over - like this. The long bit of the tool should eventually slot into the flywheel:

Image:M40timingbelt17turningtheengineover.jpg


Once you have slotted the male part into the female part successfully put the other part of the tool at the front of the cam in the head (it has a square bit):

Image:M40timingbelt18fittingthetool.jpg


Undo the tensioner and remove the belt:

Image:M40timingbelt20removetensionerandbelt.jpg


Mark up an allen key to 85mm with tippex:

Image:M40timingbelt19markinguptheallenkey.jpg


I then changed the rollers and then tensioners this is so obvious how to do it - you undo the bolts! Re-fit a new belt belt:

Image:M40timingbelt21refitnewbelt.jpg


Starting from the bottom:

Image:M40timingbelt22refitnewbelt.jpg


Now you need to set the tension - with the allen key in the bolt pull the tensioner out until you get to ..(I need to look in haynes..)....force (with the meter placed where you marked the allen key:

Image:M40timingbelt23tensionbelt.jpg


Tighten it up:

Image:M40timingbelt24tightenuptensioner.jpg


Take the timing tools off and turn the engine over by hand, making sure there is no scraping of metal:

Image:M40timingbelt25head.jpg


Fitting is the reverse of removal.....!