HOW TO: Cambelt Change (V6), Engine-in
Famine last edited by
**Okay :D Since I did this a couple of weeks ago and the car hasn't exploded just yet, I'm going to post up a step-by-step guide as best I can manage. It'll be in mainly idiot-speak because I'm an idiot and I'd have loved a guide in idiot speak when I was doing it to prove an idiot can do it…
Tools you will need**
10mm, 12mm, 14mm, 17mm, 21mm hex sockets (plus wheel locking nut, where used)
A wide range of ratchet wrenches
Breaker bar (with adapters to suit your sockets) - 2ft recommended
Torque wrenches (small, medium and buggeration my arms are falling off)
Cross-headed screwdriver (long and stubby)
Supplies you will need
Accessory belts (check they are correct, these vary if your car has PAS/AirCon)
Hydraulic cambelt tensioner - this is an option replacement. Replace it.
Philips/Douwe Egberts Senseo coffee maker and endless mugs
Your neighbours to be inside so they can't hear you swearing
14 hours of free time the first time you try this
**Okay, you ready? Let's begin. But first… it's important to read this right through before even ordering the parts. Feel free to print it off and use it as a reference alongside the job, but make sure you haven't missed anything first.
Step 0 - Preparation**
At this point, you need to decide what job you're actually doing. If you're doing a full service, including changing the filters, plugs and leads, you will make the cambelt change slightly easier for yourself though, obviously, add on a little time to the job. I don't want to make this guide any more complex than is necessary though, so I will annotate in a slightly different colour to help demarcate the tasks.
Oh, and if you've not used a ratchet or screwdriver before, clockwise tightens, anticlockwise loosens. And remember, always keep the stuff you take off in a safe place rather than letting it roll about your driveway.
Step 1 - Preparation
Disconnect the battery - negative first, then positive (or just negative is fine). Jack the front right (RHD - driver's side) of the car up. If you're feeling chirpy, jack the front left too. Pop the axle stands in place. Take the front right (RHD - driver's side) wheel off - stock size is 21mm.
In the wheel well (not in the arch) you will see a black plastic cover - the splashguard. This is held in place by a variety of 10mm hex bolts, occasionally with cross-head heads - three are beneath the car and the remainder are in the wheel well itself. Remove them and the splashguard.
What you will now see in front of you is a giant, metal wheel the size of your fists put together. This is the crankshaft pulley and probably the most important reference point and part of the engine for you right now.
Step 2 - More preparation
At this point, I'd remove the entire intake tract up to the plenum. That, for us idiots, is all the plastic stuff. It's not necessarily required for the cambelt job, but a step later on might - if your car is being badly behaved - need it. It is, however, required if you're doing a full service because it enables access to the fuel filter and distributor cap.
The intake tract is a piece of piss to remove. There's a cross-head screw securing a clip which attaches the "concertina section" to the plenum, two more similarly connecting the resonator (useless looking J-shaped bit of plastic) and air filter box to that, three 10mm head hex bots holding the air filter box in place and three 10mm head hex bolts holding the intake to the radiator mounting. This should take 2 minutes to remove.
Step 3 - Accessories
At this point, there are two tensioner pulleys to remove - for us idiots, any wheel-shaped thing which has a belt wrapped round it is a pulley, and anything that's only there to give the belt tension rather than make anything else move is a tensioner. So a tensioner pulley is a wheel with a belt on it to give the belt tension. Simples.
As you look at the crankshaft pulley from underneath, you'll see one belt going ahead of the engine and one going to the rear. Let's deal with the one ahead of it first.
Underneath the engine, follow the belt forwards (try and note which way round the writing on the belt is - you'll want to put whichever belt you put back on later the same way round) until it gets to the tensioner pulley - it'll be above and forwards of the crankshaft pulley. It is held in place by a single 17mm hex bolt. Get your 17mm socket on it and just crack it loose - don't unbolt it all the way, just loose.
Get above the engine and look to the left side where we're working and cast your eyes forwards. There should be an obvious - and long - 10mm head bolt coming right up at you. This will appear to go into a bracket behind one of those tensioner pulleys. Get your 10mm socket onto it and tighten it (clockwise on the ratchet). This might seem counterintuitive, but the bolt has two threads. One attaches it to the bracket, the other tensions the belt. By tightening it, you release tension on the belt and, after a couple of full turns, the belt should slip right off.
Follow exactly the same procedure for the belt at the rear, with the exception that the 10mm tensioning bolt is only accessible from under the car this time. You can feel free to remove both 17mm nuts at this point along with both the tensioner pulleys.
Now return to the tensioner pulley at the front (or where it was). You should be able to see that it's mounted on a triangular bracket. Remove this bracket - there will be a 10mm bolt at the bottom and a 10mm (long) bolt at the top/back. Remove, take the bracket out and store in a safe place…
Step 4 - More Pulleys
Your next step is to take off the water pump pulley. This is relatively obvious, but, for us idiots, it's the one the back belt used to go over before you took it off and it has four bolts in it. Each is a 10mm hex head. I'll forewarn you here that this might be tricky, because if one of them is a bit tight you'll just be going round in circles. Try to brace the opposite one with a 10mm spanner and don't take any out until they will all move freely. It's a sound method for three of them, but the fourth might be a nightmare. Persevere.
The power steering is next. First find the power steering fluid reservoir - it's front-left of the engine and has a big black pipe going into the top. It is held in place by two 10mm bolts. Remove these, position the reservoir away from the engine and secure it with wire or string.
Return to where the tensioner pulley for the back belt was. Above this is a big wheel (pulley!) with four slots in it. Through three of the slots there ought to be 12mm bolts showing. Put a socket and ratchet onto one of these (the front-most one is your best bet) but do not turn it. Next put the appropriate socket & breaker/spanner (I don't recall the size offhand) onto the nut in the centre of the pulley and remove it, using the first socket as a brace to stop the pulley rotating. Remove the pulley.
Now you'll see the bracket that held the pulley on - it kinda looks like two triangles, point-on-point. It is held on by three 10mm bolts - one in the middle and one each bottom-front and top-front. Remove them and keep the middle one aside - you'll see it's quite a bit longer than the others…
Now the power steering pump is free you need to position it away from the engine also, and secure with wire or string.
Step 5 - The biggest pulley of all
Remember the Crankshaft pulley? Well, now we're removing it and it doesn't take a thorough search of this site and the Canadian one to find out what a :evil: ing load of :evil: :evil: this is…
The upshot is that this one bolt holds the crankshaft pulley onto the crankshaft. And when you turn it, the crankshaft turns - and it's tightened to a torque greater than that which the engine can deliver... So you need to prevent the crankshaft from moving while undoing this nut (and later the same, but when tightening it).
What people advise is to put the car in 5th and have someone stand on the brakes. I'll save you time now - this doesn't work unless the bolt is undertorqued. So you're left with:
1. Accepted method. Buy the Specialist Service Tool: Crankshaft locking tool. :evil:. That.
2. Immobilise the crankshaft. The long 10mm bolt you pulled from the middle of the power-steering pump bracket at the end of the last step is a perfect fit (M10 x 1.25) for the holes in the face of the pulley. Screw one in nice and tight, use a gigantic chunk of metal to slide between that and the nut and brace it on the ground or against a hefty piece of engine bay.
3. Immobilise the flywheel/clutch. If you've taken the intake tract off like I said in Step 2, you will be able to see the starter motor (right side of engine, low down. Wires going into it, looks a bit pointy). This is secured by three 14mm bolts - two at the front and one which is really hard to get off at the back. Once these are off, remove the starter motor and you now can see the flywheel and clutch. Follow the example of this picture, using your biggest, thickest and not-cheapest screwdriver - don't put it anywhere else - and brace it while someone else with a two foot breaker pulls his spine out trying to undo this :evil: ing bolt.
We used method three. It works.
Once this is done, pull the pulley off. It may need encouragement with a rubber mallet, but don't overdo it.
Behind the pulley is the crank position sensor and an electrical connector you should now disconnect.
Step 6 - Getting under the covers
Okay, you're now ready to make a go of removing these covers… Only one thing stands in your way - the driver's side engine mount. Uh-oh.
Bring your engine lift in. Put the hook on the front engine lifting point and pump the lift enough that the chain becomes taut. Give it another half-pump and ignore it.
The engine mount is held by three vertical bolts and one horizontal one. Crack the horizontal nuts first - 17mm - and you'll note that one of them is actually oval inside. Remember which it is (I know I forgot) for when you come to replace it. There will also be an Earth wire terminal between the two nuts at the front.
Put a 17mm spanner on the nut end of the horizontal bolt and use a 17mm socket to remove the bolt. If you sense at any point that the weight of the engine is bearing down on the bolt, gently raise the engine lift a little and try again.
Once this is clear, remove the mount. You may also wish to remove the bracket on the engine to which the mount was attached - this is again, just three bolts (also 17mm).
And now you are clear to remove all the 10mm head bolts that attach the cambelt covers to the engine. Be aware that some of them (top/back) also attach to small metal brackets carrying part of the engine wiring harness and one (middle/front) attaches the dipstick pipe. There are :evil: ing loads of these and there's bound to always be one more than you think - any time the cover has a recess in it, there's a bolt in there.
Once these are all clear, remove the cambelt covers. They split into two - front and back - and the front should come clear first.
Step 7 - The belt itself…
Now, the easy part. :D
This next image isn't mine, but you will have seen it before if you're interested in changing your V6 cambelt. It comes courtesy of tunes67 on MX-3.com:
Turn the crank (big one at the bottom) or one of the cam gears (two big cartwheels up top) until the yellow timing marks are aligned with notches in the casing. You can see the correct orientation in that image - this is what's known as "Top Dead Centre" (TDC) for the crank. Now let's get to work.
Bolts 1 & 2 are the infamous hydraulic tensioner. You will be replacing this part. Yes I know it's £90, but look at all the crap you've just gone through to get to this point that you'd have to do again when it fails - and it will fail. Crack bolt 1 (12mm), remove bolt 2 (12mm) and the remove bolt 1. Unless you're replacing the other circled idler pulleys - and unless they're worn or you're upgrading, there is no point - ignore and move on.
Now at the top of the engine is an idler pulley. Remove this as well (14mm bolt). And off with the old belt. Junk the belt.
Install your new hydraulic tensioner with only the top bolt in place. Nip it up, but do not tighten it yet.
Step 8 - In with the new…
This is separate to the above because it is important. One the hydraulic tensioner is engaged at the end of this step, you are done for if you have done it wrong, so pay attention, Bond.
Put the new belt on so that the writing is the correct way up as you look at it standing by the driver's side of the engine bay. Loop it over the components IN THIS EXACT ORDER:
1. Crankshaft (important bit, at the bottom)
2. Front idler pulley
3. Front cam gear
Ensure there is tension in the front side (that is, what you have just put on) of the belt
4. Autotensioner pulley
5. Rear cam gear
Ensure there is tension in the rear side (that is, what you have just put on) of the belt and slack on the top of the engine between the two cam gears.
Now reattach the top idler pulley (14mm) bolt. This is easier with two people - one to push the pulley down and the second to install the bolt. Un-nip the top bolt (bolt 1) on the hydraulic tensioner, install the bottom bolt (bolt 2) and retighten the top bolt.
Now check that all the timing marks are in the right place - that is the same place they were when you removed the belt, and the same as in the picture in Step 7. If they are not, you will have to repeat step 7.
It is far better to repeat step 7 twenty times than it is to fix the consequences of thinking "ah, that'll do it".
Once you are sure the belt is on and the timing marks are correct, torque the bolts up correctly:
Bolt 1 (hydraulic tensioner top): 17lbft
Bolt 2 (hydraulic tensioner bottom): 17lbft
Bolt 3 (top idler pulley): 30lbft
Now remove the hex key/wire that is preventing the hydraulic tensioner from engaging.
Your next step is to rotate the crankshaft one full revolution (or rotate one of the cam gears by two full revolutions) and recheck the timing marks. Then do this again. If the timing marks are fine, we'll start the closing up procedure. If they are not, you're looking at repeating the entirety of steps 6 and 7 - and recompressing the hydraulic ram (which must be done slowly and carefully in a vice). Hopefully they are.
Step 9 - Assembly is the reverse of removal
And now steps 5-0 backwards… Your biggest worry now is overtightening.
1. Reattach the covers and install all the 10mm bolts, tightened to slightly-more-than-gloved-finger-tight. If you have a lbin torque wrench, 83lbin is doing it properly
2. Remember to reattach anything attached to these bolts - engine harness brackets, dipstick
1. Engine side bracket if you removed it - 3, 17mm bolts to 38lbft
Leave the mount itself for now...
1. Install and nip the nut up.
2. Immobilise the pulley as before and torque to 120lbft
1. Reinstall starter motor
2. Locate and torque the 3 14mm bolts (32lbft)
Water pump pulley
1. Install the pulley and locate all 4, 10mm bolts. Torque to 83lbin
Power steering pump
1. Reinstall the bracket. Bottom and top 12mm bolts torqued to 22lbft, central 12mm bolt torqued to 39lbft
2. Reinstall the pulley. 12mm bolt torqued to 58lbft
3. Reinstall the reservoir. Two 10mm bolts torqued to finger-tight :D
Accessory belt tensioner pulleys
1. Rear - fit the pulley to the bracket and tighten 17mm bolt to "tight".
2. Front - install bracket. Two 10mm bolts, torqued to 22lbft
3. Front - install pulley and tighten 17mm bolt to "tight"
1. Fit inside belt, then adjust tensioner adjuster bolt (10mm) until the belt will not deflect more than 8mm with fingertip pressure.
2. Fit outside belt, then adjust tensioner adjuster bolt (10mm) until the belt will not deflect more than 8mm with fingertip pressure.
2. Install horizontal nut/bolt and nip up
3. Install vertical nuts - remembering which was the oval one, and to put the ground wire terminal between the two left bolts.
4. Torque vertical nuts to 65lbft
5. Torque horizontal nut/bolt to 60lbft
6. Relax and remove engine lift
1. Reinstall intact tract (10mm bolts)
1. Reinstall splash shield (10mm bolts)
1. Reinstall wheel (21mm bolts), remembering not to torque up until car is grounded.
2. Jack up and remove axle stands.
3. Torque up wheel bolts
Step 10 - Now go enjoy it, you pillock
I have a couple more images to add at some point, but it's really difficult to get a ratchet into some of these places, never mind a camera…
I'd recommend printing off this page as a handy "oh, so that's what it looks like" guide in the meantime.
Hopefully, this will help those of you as inept as me. And after all, I did it (kinda).
ukmx3admin last edited by
A couple of suggestions
loosen the waterpump pully bolts while the belts are still on as its much easier
Instead of an engine hoist you can just put a jack under the sump. Use a lsrge flat bit of soft wood on top of the jack to protect the sump. I like using a trolly jack as its quick to raise/lower the engine as you need.
I would also be thinking about doing a new water pump while I was at it!!