Thread: tdi300 timing belt.

start out by draining the cooling system, use clean hoses and bottles if you want to reuse the coolant. Typically If Im doing a timing belt I'll pull the system apart flush everything and change the hoses. If you're not doing this then you can get away with just draining the radiator half way and reusing your coolant.

undo the cap on the expansion bottle and start syphoning.


While thats happening remove

1. the top of the shroud
2. 2 clips that secure the radiator shroud to the radiator top panel
3. the radiator top panel
4. the viscus fan hub(36mm LH thread, belt it with a hammer)

now start draining the radiator proper by removing the top bung and inserting a small hose, theres a baffle halfway down the radiator, its got a hole in it about half an inch in diameter that will usually stop you from getting the hose all the way down to the bottom, I usually get the system drained untill it becomes visable and then get the tube down the bottom and restart the syphon.

• all battery earth connections
• the intercooler hose
• the top radiator hose

you should be looking at something like this

unhose, unbolt then remove the crank case ventilation filter and the rocker cover



Remove the serpentine belt, 15mm spanner on the idler and lift them peel the belt out from under the tensioner.


remove the cover from the AC pump loosen off the 3 bolts on the tensioner, remove the ac drive belt.



remove the tensioner

now grab a 27mm (your wheel nut spanner if your kit doesnt run that high) and put it onto the crank pully bolt. turn the engine over by hand watch valves 1+2 and 7+8 (valves are on the rock if the inlet valve is opening at the same time as the exhaust is closing) if 1+2 are rocking you are 1 full turn out on being able to commence work and if 7+8 are rocking your close. As you turn the engine just after the exhaust valve for the #1 cylinder closes a mark will pass TDC on the harmonic balancer, grab a paint pen and mark it so you can see it clearly then keep turning the crank.

theres a timing mark on the front of the timing belt case, when you have it looking something like this
with valves 7+8 rocking you should be able to insert the timing pin into the pump drive gear.

IF you get that in crawl under the vehicle look at the bottom of the bell housing and look up into it you should see

if it looks like that grab a screw driver and lever the timing slot into the middle of the hole.

now screw in the timing bolt. (if you have one, you dont need it but it does make life easy)

undo the front nut, 27mm you have 3 options.
firstly I normally by this stage have the radiator and intercooler removed for flushing, this gives enough room to get in with a 27mm and a rattle gun so that makes it easy and normally leaving the vehicle in gear is enough resistance to let you break it loose with just a breaker bar and an assisting bar.. heating the whole thing up wtih a hot air gun make it easier again.

Ok so you have an auto... (and this is why you read the whole instruction BEFORE you start work) you can (and I dont normally reccomend this) get the bolt off by placing your breaker bar and socket on the nut turning the engine over by hand in the normal direction of rotation and then when the bar is resting on the chassis rail then keying the starter.

you can also remove the glow plug from one of the cylinde, turn the engine over till it starts to blow air out that plug hole turn the crank about 180 degrees more then wind the adjuster in on the exhaust valve (to open the exhaust valve to let the air out) and inject about 100ml of engine oil wind the adjuster off and put the glow plug back in. youve now effectively hydrauliced one cylinder, with that providing resistance to the crank undo the pully nut.

neither of these things you can do if youve followed the steps above in order because the battery will be disconnected if you want to use the starter OR the timing pins and bolts will be in stopping you from turning the crank.

the third option is to use the timing pins to hold the crank. It works, I just dont like it. I've never had one fight me past a rattle gun yet and you shouldnt either.

ok so with the bolt cracked loose wind it most of the way out so its there to hold the pully when you pry it off.

insert your levers of choice between the timing case and the crank pully lever the pully off the crank.


lever on the heads off boltsnot on the ally timing cover, you can crack it. The ones painted white are the ones that I use


undo the plethora of bolts that hold the timing cover on and pry it off, dont mix up the bolts theres a few different lengths in ther. I lay them out on the replacement gasket , remove the cover clean the gasket off of the cover and then place the bolts back in their holes on the cover.

Now grab your paint marking pen THIS NEXT BITS CRITICAL IF YOU DONT HAVE A SET OF TIMING PINS and pretty important even if you do. on the injector pump gear mark 3 of the teeth on the belt and 2 of the teeth on the gear so they interleave. Mark 2 teeth on the belt over the cam gear and one tooth on the cam gear then mark the back of the belt over a tooth where its just engaging on the crank gear and the same place on the face of the crank gear (remember to transpose this mark if you replace the crank gear.

If you are doing this without a timing pin and a bolt now wind off all the valve adjusters, if the cam gear wants to move on you and you dont have a helper or a tool to hold the gear (I use a spanner that I lean on to hold it while I faff round with the belt) also remove the vac pump and the fuel pump.


now using the 8mm allen key loosen off (dont remove) the allen head bolt in the tensioner wheel then remove the idler pully nut and the idler then remove the belt

now undo the allen head bolt and remove the tensioner (you can see the marks on the gears in this pic 2@12 on the pump gear, 1@12 (and the timing mark aligns at about 7) on the cam gear and 1 at about 1 oclock on the grank gear (and the woodruff key is vertical)

I'll say it again. PAY ATTENTION TO THE POSITION OF THE GEARS AND MARK THEM dont rely on what should be in postion being in position I have seen these things 180 degrees out of phase with each other..

now count the teeth on your old belt and on your replacement belt ensure they're the same and then transfer the marks from the old belt to the new one. DOUBLE CHECK THIS measure twice, mark once. Dont cut.


marking the belt is very very important if you're doing this without the timing pins.

Originally Posted by Blknight.aus

the viscus fan hub(36mm LH thread, belt it with a hammer)

Hi Dave,
As usual great tutorial

Viscous hub is 32 mm isn't it? At least mine is.

Tony

Dave, also worth mentioning here that a few of the very first 1994/5 300Tdi's used a bigger 1 3/16" crank bolt head (like the 200 tdi) instead of a 1 1/16" (27mm) one like you have on that vehicle.

JC

Ok, somewhen I made a snafu... my home made 32mm spanner is actually a 36 and my 36 is a 32....

Since I usually carry both and just grab one and if its not right I use the other.....

my bad yes, its 32mm for the tdi. When I beg borrow steal permission to edit the posts for typos spellos gramos and snafus I'll sort that out.

here comes part 2.

get in there with some fresh running water and a tooth brush, clean out all the loose carbon looking stuff thats been thrown off of the old belt, while your at it remove the woodruff key from the crank and very lightly wire brush the nose of the crank to remove any rust. (put the woodruff key back)

apply loctite 243 to the tensioner screw and the idler stud, insert the tensioner idler and put in its allen head screw about 3 turns, locate the pivot point of the arm onto the idler pully and then torque down the nut. With the loctite on the screw you only have 15 minutes to complete the next bit and torque up the tensioner screw. If you need to have a dummy run with the old belt and no loctite OR dont loctite the tensioner screw carry out the following steps then Remove the tensioner screw loctite it and reinstall then torque it up.

you should be looking at this


Now the fun bit getting the belt on.....

I start at the cam gear, Line up the paint marks on the gear and belt then slide it onto the cam pully, grab a suitable size bit of toolage to wedge beween the pully and the housing to hold the belt in place, a 3/8th drive extention bar works. Slide the belt between the tensioner and the idler then around the crank gear, line up the marks youve made (I guide it around with my right index finger while using my left hand to guide the belt back up between the idler and the tensioner). holding it in place against the tensioner I then insert a small chisel between the crank gear and the housing to hold the belt in place.

you should now have a loop of belt that wants to try to go over the injector pump pully I guarantee you cant get it onto there without some trickery. you have 2 choices.


My preferred option is to put a double offset ring spanner onto the injector pump pully nut lever it forwards slightly, remove the timing pin let the injector pump spring the gear back 1/2 a tooth width then guide the bottom of the belt onto the gear, while holding it in place with my left thumb (right hands busy with the spanner) push it part way onto the gear at about the 7 oclock position then work the belt on at about the 8 oclock position with your forefinger. By shuffling the IP gear very slighty and "walking" your fingers clockwise around IP gear the belt will slide on. Once youve got it on re-insert the timing pin, If you cant you missed by a tooth and this should be reflected by the marks you put on the IP gear. reverse the process move the gear the desired tooth and go again. Once you have the timing pin in duck under and check the position of the crank (if you dont have a crank locking bolt)

The second option is to back off the nut on the idler, slide it forwards about 3/8th of an inch and let the tensioner pivot slide onto the stud, install the belt (the extra movement of the tensioner will free up enough slack for you to just slide it on) then relocate the tensioner arm on the idlers shoulder and torque the nut back up.

once you have all that done you should be looking at this.

The following is my FIELD method of doing this without any tools, There are some parts you can skip if you have enough tools and a helper. If you are doing this because you've suffered a failed belt you will need to sort out the pushrods and the rockers, as most people dont carry a spare belt, idlers, pushrods, rocker rams, adjusters, valve cap buckets make sure that you get them all sent to you, If you're attempting this on the side of the road, I STRONGLY recommend that you check the valves and pistons for damage primarily from a compression point of view. If you dont know how to do this then you should probably not be attempting this. If you are in this boat when you order your timing belt order a replacement head and head gasket kit and replace the head. Ensure that prior to ordering you have removed the head and checked the pistons If they are badly damaged you need to re-asses your options.

On with the fun.


Start by lining up the crank
back off all the rockers completely (If you've pulled the head this step is redundant)
remove the vac pump and the fuel pump (if you have an assistant to hold the cam pully nut with a spanner this step is redundant)
identify the timing mark on the cam gear, count teeth on the way around and mark the cam gear at 180 degrees from the timing mark.
line up the cam gear to its timing mark (a bolt tower with a spine on it, the spine is the timing mark for the cam gear) using a ruler across the marks you've made (this is to eliminate parralex error, if you have the radiator out you can get an eye one it directly and the last two steps are redundant)

carry on with the first half of the previous instructions when it comes time to do the IP gear you must manually hold it with the spanner, to zero in on the correct location use a phillips head screwdriver in the timing hole, wiggle the screwdriver, if it doesnt tilt equally on a tangential plane turn the gear in the direction that if falls short on.

dutchish? ok.

notice that the timing pin fits in and is EXACLTY parrallel to the teeth of the timing gear, pretend that timing pin went in at 12-oclock if you could wiggle it left to right it would pivot if it pivoted more to the left side than the right then the gear needs to be turned towards the right to bring the 2 holes into alignmnent.

once you have that worked out install the timing belt as per the second half of the previous instructions. (and tension the belt)

To verify your work....

Prime the fuel system and power up the injector pump solenoid (or remove it)
turn the engine over by hand using the rule of 5 (cylinder rocking + cylinder firing=5) with the injector lines cracked if an injector is trying to fire as its partner cylinders inlet valve opens than you have the cam - IP phasing correct. realign the crank timing mark again and recheck the injector pin hole for clearance IF the screwdriver moves equally either side of parallel to the teeth of the gear then you have the timing correct.