Timing (Cam) Belt Change
The 1.9 diesel (XUD & XUTD) engines are classified as Class 5 (Interference) – a catastrophic collision of pistons and valves will occur if the exact relative position of crankshaft and camshaft are lost (because the belt breaks, jumps several teeth or through incorrect assembly); a replacement cylinder head is likely to be the cheapest, if not only, option. If the injection timing is lost the engine won't run properly if at all.
Citroen recommend a 76,000 mile interval (or 10 years). Accepted wisdom is that belts should be changed roughly every 50,000 miles or 5 years, whichever occurs first. Quite a lot has to be removed to get at the timing belt, reckon on at least a day for the complete job.
The Haynes Handbook is a help, particularly with illustrations, but some vital details are missing or wrong; I hope I’ve covered these here. I've now done the job three times and revised these notes in March 2014.
All diesel Xantias left the factory fitted with an engine under-tray; Citroen had good reasons for the considerable extra cost, including:
- It helped meet the EU drive-by noise regulations
- Improved fuel consumption
- Improved air flow through the engine radiator, inter-cooler and A/C condenser
- Protection of the entire engine bay from debris, stones, grit, mud, salt, spray, frozen snow and ice; all of which damage and corrode.
If your Xantia still has one (many get thrown away by lazy mechanics), I strongly recommend that you re-fit it.
While the ‘front’ of the engine is exposed and all the belts are off: check the crankshaft and camshaft oil seals (you can't see the latter without removing the sprocket but any leak will be down the 'end' of the cylinder-head and very obvious), and the water pump, for leaks. If any of them show any signs of leaking, change them at the same time. Oil contamination will shorten belt life, and a water pump weeping coolant will fail shortly because the inner water seal is leaking water through the "lubricated-for-life" bearing.
My friendly local mechanic (who used to do a lot of work on the NA XUD engine in vans) reckons that it's essential to remove both tensioner and idler for inspection. Given the labour involved in changing the belt, for the extra £50 or so, fit a tensioner kit rather than run the risk of having to do the next belt change early when either the tensioner or idler starts to fail.
Complete failure equals wrecked engine! On my Xantia at 68,000 miles, slack in the idler bearing was just detectable and it was starting to leak grease slightly - it wasn’t going to last another 50,000 miles or 4 years to the next scheduled belt change. In any case, replace them both at every other belt change – every 100k or 10 years.
The crankshaft bolts are known to come undone and to break, so always use a new one (£2.50) when refitting the crankshaft pulley. A bolt is not usually included in a belt kit (belt, tensioner and idler).
If the belt has ever been changed, the paint seal on the nut (and stud) that secures both upper and front belt covers will be broken.
In addition to a basic tool kit, you will need:
- 21mm ring spanner for the injection pump nut (to carefully and slowly rotate the engine to alignment).
- 22mm socket (½" drive) for the crankshaft bolt – if you have to buy one, choose a hex impact socket.
- A BIG (900mm) ½" breaker bar for the crankshaft bolt.
- Torque wrench
- Small LED inspection lamp.
- A 'mirror on a stick' is a big help.
- Cam-belt Tensioner tool (10mm square drive). Two options:
- Buy an expensive 'proper' one,
- As 3/8" square = 9.5mm is slightly smaller than the 10mm square hole in the tensioner arm, a 3/8" drive 3" extension can be used. I found that a Molegrip clamped on a 70mm extension were the only thing to hand that would fit between camshaft sprocket and inner wing. Now I've bought a skinny 3/8” ratchet, that's much easier to use and less crude, than the Molegrips. The extension is looking slightly chewed - one day I'll buy a decent quality replacement.
- Timing 'pins':
- the ideal alignment bolts are: 2 off M8 x 45mm (ordinary hex head) for the injection pump, plus 1 off M8 x 50mm cap head (not enough space for a hex head) for the camshaft sprocket.
- Flywheel alignment pin: Cut off the head of a long M8 bolt with about 50mm un-threaded. Grind or file down the last 10mm or so (of the plain end) into a good taper. Wind 4 or 5 turns of about 1m of fairly stiff (fence) wire round the threads; unwind from the threads, and over-wind the 'spring' so it grips the pin's threads. Bend the free end 45º to the axis of the spring and make a loop in the end to form a handle.
- Lilo pump, 'duster' aerosol or some other means of blowing out the thread in the crankshaft end.
- Digital Camera; take some extra photos as you go to remind you what goes where and how.
- Jack: The engine has to be supported from underneath as the lifting bracket has to be removed for access to the automatic tensioner spring. Support the right-hand end of the engine on a jack with a short (about 250mm) length of timber (4” x 2” minimum) or a piece of good ply (15mm minimum) about 150mm wide bridging the sump and the rear engine mount. The right-hand end of the engine can then be slightly raised or lowered to marginally improve access to its end and back. The height of a trolley jack can't be safely adjusted by small amounts, it's easier and safer to use the cars own jack.
- Axle Stands: NEVER EVER work underneath a Xantia unless (that end of) the car is securely supported on axle stands.
- Component Storage: Cheap polythene tie-handle freezer bags are a good way to keep fasteners and small components with the corresponding larger components. This saves muddle and wasted time.
- Timing Belt
- Crankshaft pulley bolt
(1,2 & 3 are often available more cheaply as a kit)
Sequence of Operations
- Remove the under-tray (if there still is one fitted!)
- Support O/S jacking point on an axle stand.
- Suspension on High (so the car can't move up and down).
- Remove O/S front wheel and inner wheel-arch liner.
- Release tension on Auxiliary Drive Belt and remove tensioner and belt.
- Remove crankshaft pulley/damper.
- Remove lower Timing Belt Cover.
- Remove front Timing Belt Cover.
- Remove Air Cleaner top (and element) and stuff a ball of newspaper in the hole
- Remove plastic air pipes over the engine
- Remove top Timing Belt Cover.
- Rotate engine to align timing bolt on camshaft;
- Fit timing 'pin' to crankshaft, timing bolt to camshaft, timing bolts (x2) to fuel pump.
- Take tension off timing belt and remove.
- Remove cam-belt tensioner and idler for inspection.
Re-assemble in the reverse order after carefully cleaning crankshaft pulley face, bolt and washer.
The bits that Haynes doesn't cover too well.
(6) The crankshaft bolt can very difficult to undo. Pull the handbrake on hard and put the gear box in 5th. With your big breaker bar and 22mm socket you should be able to shift the bolt. It's unlikely now to be as it left the factory (very tight - an impact air-wrench at its maximum setting of 160ft/lb wouldn't budge mine). Failing the breaker bar, you have to use the starter: reconnect the battery, rest the end of the big breaker bar on a piece of wood (not on concrete or similar). Put the gearbox in neutral, and with anyone well clear, a quick flick (no more) of the starter should undo it. This trick has been known to shear off the bolt head! The factory used Locktite on both faces of the thick washer under the bolt head, gluing the bolt head to the pulley face. I would never re-use a crankshaft bolt that was really difficult to undo.
The crankshaft pulley may come off easily once the bolt is out. Sometimes it's stuck on the taper. It's a casting, so expect to break bits off if you hit it with anything hard! Two M6 tapped holes are provided for a puller. DO NOT use a gear puller or a lever on the pulley rim – you'll break the rim and wreck its balance. If you have a two-legged puller, find a couple of short M6 bolts with well-fitting washers (under tray bolts), screw them into the pulley so the puller's legs will just go under the washers as shown in the photo (right). The pulley should then come off quite easily.
(10) Timing Belt Covers Trust me, it's much easier to get the top cover off if the air ducts are first removed. Start by removing the air cleaner cover and its duct. The other mountings and connections on top and in front of the engine are obvious but take some digital photos as you go so you know how it all fits together. Finally you are left with disconnecting the two ducts that disappear down the back of the engine to the turbo-charger, shown (right) re-assembled on the floor; the 'whiskers' are cable-ties keeping the set-screws in place. Plug the open inter-cooler hoses with newspaper.
With an inspection lamp shining down the back of the engine, the front set-screw (10mm hex head) is just visible between the top of cam-case and the inlet manifold. The duct had to be removed to get the camera into place. Now you can feel where the rear set-screw is. You need a ¼” drive 10mm socket on the end of an extension (about 100mm) and a ratchet. Crack-off both screws before undoing them in turn. The safest way to remove them is with a magnetic retriever (you do not want to lose one down the back of the engine!). With a bit of waggling and manoeuvring this duct can then be removed. Stuff the turbo-charger outlet with a piece of clean rag – any cr4p that drops in there will trash the turbine and the debris will be force-fed into the engine! Now you can see where the other duct joins onto the turbo-charger air inlet via a flexible rubber pipe. Undo one of the two 'Jubilee' clips with a 7mm socket - the outer for choice, leaving the hose on the turbo-charger. Remove this duct. When you put the outlet duct back on, use a magnetic 'retriever' to position the bolts in the holes through the duct's flange. Recovering a dropped bolt would be nightmare.
(11) Now for the belt top cover fasteners. One is fairly obvious, the other is one at the back near the top and screws into the cylinder head (the camshaft end bearing housing); even with the air ducts removed it's invisible without a mirror and the fuel return pipe sits on top of it - push the fuel pipe out of its clips to get at the (11mm hex head) set-screw - beware, it's angled upwards by the tilt of the engine.
(12) Alignment Pins Before removing the cam belt, fit all the pins (Flywheel, Camshaft, Injection Pump). The flywheel pin (arrowed right). You will find that if you poke this behind the starter in line with the joint between the starter body and solenoid it will find the 'chute' cast into the front of the block and slide towards the timing hole. You will know when it's in the timing hole, as it will hit the flywheel with a distinctive ringing sound. Turning the engine over (belt moving towards you) with a socket and ratchet on the fuel-pump drive nut. If you watch the camshaft pulley, you will know when you are near the timing point as the timing hole in the cam pulley will head towards 4 o'clock. Fit the cam (1 x socket head) and 2 (hex-head) pump timing bolts. Refer to the picture in section (14) below – the sprockets are correctly aligned, but the 'pins' aren't in place (magenta arrows). Wind the locking 'pins' (bolts) in so that they are well in but there is still a bit of wobble. The crankshaft pin should now locate, but the crankshaft may need rocking ever so slightly for it to slide all the way in. Finger-tighten the sprocket pins.
What to do if the timing pins won't all line up:
If the timing has 'jumped' because bits of shredded auxiliary belt have gone between the cam-belt and the crankshaft sprocket, then the pins won't all go in at the same time with the cam-belt still in place. If you're lucky, jumping one tooth may have caused a horrible (big-end gone) clattering without doing any damage.
The photo (right) shows the crank-shaft sprocket alignment at TDC with the flywheel locking pin in place: the crank-shaft sprocket key (red arrow), its corresponding sprocket tooth (green) and the cast circular mark (blue) are aligned.
If necessary, turn the crankshaft one crankshaft sprocket tooth to lock the camshaft and pump sprockets with the pins in the positions indicated by the magenta arrows. Remove the tensioner and belt (see 14 below), before turning the crankshaft back to the correct position and inserting the flywheel pin as above. Do not force the engine to turn over if there is significant resistance! You will bend or break something!
Make a couple of cards that say TIMING PINS FITTED, park one somewhere obvious in the engine bay, and tape the other to the steering wheel.
(14) The tensioner pinch bolt is below and behind the camshaft pulley (top red arrow) - it can just be seen by looking down behind between the pulley – just loosen both it and the nut (lower red arrow).
Using your ‘tensioner tool’ (see Tools above), rotate the tensioner anti-clockwise as far as it will go. Nip up the pinch bolt. Remove the slack belt. Hold the tensioner with the 'tool' while you loosen the pinch bolt until you can ease off the tension. Hold the tensioner in place and remove the pinch bolt. Ease the tensioner off its pivot (bottom red arrow) with one hand, with the other ready to catch the plunger and spring (green arrow). There's no need to disturb the tensioner bracket (yellow arrows) unless the cylinder-head is also to be removed.
Remove the idler (blue arrows). Inspect tensioner and idler. Both should run as smooth as silk with no slack in the bearings nor any trace of grease leaking – if in any doubt, replace them. If either of them fail, the belt is likely to jump several teeth – serious damage. Inspect the water pump at the same time. As the engine has to be stripped this far to get at it, if it shows any signs of leaks or bearing wear, replace it. There are 5 bolts – it's easy to miss the left-most one outside the timing casing.
The spring-loaded plunger (green arrow above) that provides automatic tensioning makes the tensioner a bit of a sod to re-fit. The tensioner rotates on a pin - make sure this is free of rust and lightly lubricated so that the tensioner sleeve slides smoothly onto it.
Clean and lightly grease the plunger and spring. The plunger and spring WILL fall on the floor – so spread a large clean rag or dust-sheet on the floor to save having to keep cleaning them. With the tensioner ready to hand, fit the spring and plunger. Using the idler as a fulcrum for a suitable lever (with no edges to mark the idler wheel) carefully lever the plunger upwards as far as it will go (until the corner of the bracket gets in the way as in the photo - right).
Push the tensioner onto its pivot and under the plunger as far as it will go; the mounting bracket will stop it going the last 5mm or so. Now from below, with the end of a hammer handle or similar, push upwards and then sideways on the tensioner flange that the plunger rests on. With the plunger compressed, the tensioner will then slide fully into place. Pressure on the plunger can now be released so the tensioner jams against the edge of the mounting bracket. Fit the nut on the tensioner pivot. With your 'special tool' rotate the tensioner fully clockwise against the spring and lock off with the pinch-bolt.
Now fit the timing belt carefully – teeth to sprockets, smooth back to idler and tensioner wheels: Over the camshaft sprocket, round the pump sprocket, between the idler and the bracket (where the lever is in the photo), down round the crankshaft sprocket, round the water-pump sprocket and inside the tensioner. Once it's following the right path, take out the slack: hold it on the teeth of the camshaft sprocket, lift it off the teeth of the fuel pump sprocket and pull out any slack before re-engaging on the sprocket. Repeat for fuel-pump to crankshaft sprockets. There must be no slack in the belt from camshaft to fuel-pump to crankshaft, all the slack must be between the crankshaft (via water-pump and tensioner) and the camshaft. Carefully release the tensioner and check there is only the slightest slackness from camshaft to fuel-pump and fuel-pump to crankshaft. Nip up the tensioner pinch bolt but don't tighten the pivot nut. Personally I like to replace the pivot nut with a 'stiff nut' – an all-steel self-locker.
Now you need to reverse the dismantling sequence back to:-
(6) Crank-shaft pulley.
Have you removed all three sets of timing 'pins'? If so, you may now remove the TIMING PINS FITTED cards. Clean any rust and old Locktite off the crankshaft taper and the bore of the crank-shaft pulley. Wipe a trace of WD40 over both. DO NOT get any elsewhere on the pulley or down the hole in the crankshaft. Thoroughly clean the threads of the OLD bolt with a wire brush; DO NOT use WD40 or any other fluid, as it's vital not to contaminate the crankshaft thread. To tension the timing belt, re-fit the crankshaft pulley but for now use the old bolt. With a socket on the crankshaft bolt-head, turn the engine over (as though tightening the bolt) at least two full crankshaft revolutions (SLOWLY and GENTLY). Then release the tensioner pinch bolt to take up any further slack before finally tightening. Tighten the pivot nut. Check all three timing pins will still fit.
Lock up the engine by selecting 5th gear (the handbrake should still be on tight). Remove the old crankshaft bolt. Blow out the crankshaft thread as thoroughly as possible with air. Fit the new bolt, using thread-lock on both faces of the washer under the bolt-head, and, unless it's a new bolt with a pre-coated thread, the bolt thread. Fit and tighten the bolt to 60 ft/lb (40 NM) and then rotate a further 60° (or exactly one flat) without wasting time before the thread lock sets. You will need a big bar to do this accurately enough.
Finish the dismantling sequence in reverse.
Hesitant starting, with clouds of white (unburned) diesel vapour from the exhaust is a sure sign that one or more glow-plugs need replacing.
Individual glow-plugs can be checked with a DVM once they have been disconnected from the electrical feed; a good plug should have a resistance of around 1.2 Ω, while dead plugs will be open-circuit. However, plugs which don't glow right to the end and are thus not effective, may have a resistance not much different to a good one.
The middle two plugs are fairly easy to get at and check in situ; access to either of the end two requires some dismantling and even then is awkward.
Only use genuine BERU plugs, about £8 each (2015) from GSF - you might as well change the lot and save any good ones.
Tools & Consumables
- 12mm deep-cranked (the deeper the better) ring-spanner - absolutely essential, the job is impossible without one.
- 8mm ditto (not absolutely essential)
- ¼” drive wobble extensions, ratchet, and 8mm socket
- Piece of stiff wire – double over one end (so you don't spear an eye!), bend a loop in the other end like a shepherd's crook to hold the plugs when you drop them – you will, so it's worth spending 5 minutes making this.
- Torch or work-lamp.
- PlusGas or other good penetrating fluid - not WD40 or similar water-dispersant fluid.
- Loads of rag (rag is better than paper towel in this instance).
- A magnetic pickup and a mirror-on-a-stick will save a lot of time when the inevitable happens and something drops somewhere inaccessible.
- Citroen number the cylinders from the flywheel end, so No4 plug is behind the injection.
- When removed, the element (unplated) of plugs that are defective but not dead, will be sooty only at the tip; dead plugs will be sooty over most of the element length; good plugs will have elements that are clean black (except for a rusty spot on the tip where injected fuel ignites).
- Stuff loads of rag around and behind the injection pump to trap dropped glow-plugs and nuts; given half a chance they escape to hide in inaccessible places!
- Before removing/refitting each plug, wedge a piece of cloth under it - to catch the 8mm nut when you drop it!
- When removing/fitting plugs, use the wire 'crook' (see Tools) to hold the plug to prevent dropping it.
- Use Blu-Tak to hold the 8mm plug nuts on the end of your finger.
- Do the job with a warm engine – the aluminium cylinder head expands at a greater rate than steel glow-plugs, so a warm head doesn't bind (so tightly) on the plug threads.
- Do not be too brutal when trying to unscrew the glow-plugs; there is a real risk of shearing a plug or stripping the thread in the head. Either event means removing the cylinder head.
- On my '95 car the turbo pipe bolted onto the turbo outlet flange; some cars have the pipe fixed on with a jubilee clip, which is easier to remove.
- With the engine warm, spray a little Plus-Gas around the glow-plug threads (electrical connection and the plug into the head). If you can, it helps to do this several times over several days before tackling the job – then (hopefully) you'll wonder why glow-plugs are said to be difficult to remove.
- Remove the inter-cooler to manifold air pipe, and its associated brackets. If you can, remove the turbo to inter-cooler pipe also (I couldn't manage this easily, so I just disconnected the inter-cooler end, and then propped it up as high as it would go).
- Remove the oil filler to air intake breather tube.
- Remove the 8mm nut from №s 2 and 3 plugs, disengage the cables from the plugs and unscrew the plugs from the head. Do not fit the new plugs yet!
- Undo the pipe clip for the coolant tee piece on top of the engine mount and move the tee to give a bit more room. You should now be able (just!) to undo the 8mm nut on № 4 plug. Beware of dropping the spanner – if you do it's likely to lodge behind the alternator, hydraulic pump of A/C compressor, where it's a pig to extricate!
- Undo the 8mm nut on № 1 plug and unscrew the plug from the head.
- Remove № 4 plug (behind the injection pump); once you have cracked the plug you will be able to reach in behind the injector pipes (past where № 3 plug is missing) to get your finger tips to the plug to unscrew it - go very carefully when cracking the plug, if the spanner slips or you overcook it, you can break off the coolant pipe stub from the engine! Fit an 8mm nut loosely to a new plug and fit it as the new № 4 plug, tighten the plug but leave the nut loose.
- Fit the other new plugs in sequence as Change № 1 plug, and fit the new № 2 and № 3 plugs.
- Now refit the power cable that connects all 4 plugs. First snip a section out of the ring connector for № 4 plug - so that you can just slide the wire in behind the nut which is very difficult to get at. Refit the wire to the other 3 plugs without tightening the nuts and not forgetting the feed cable to № 2 plug. Only tighten the nuts (in sequence, № 4 last) once the cables are in place.
- Refit the oil filler to air intake breather tube.
- Refit all the turbo piping and brackets.
Before you pack up your tools, if you haven't already had to do so, with the aid of torch and mirror have a look below/behind the injector pump at the cylinder block flange just above the sump joint - you may be surprised at what's sitting there! I found an M6 nut, washer and a small hose-clip.