Every engine has something ugly or awkward built into its design. One example on old CIS cars is the air filter replacement, which often takes an hour and requires difficult contortions due to the air flow path often used in this fuel management design. On the wonderfully durable Audi 10 valve, 5 cylinder engine, for some odd reason the water pump is mounted almost "inside" the engine, and is driven by the timing belt. Since the belt has to be removed to get to the water pump (and the front crankshaft seal), these parts are usually replaced together. This job is one of the more intense bits of work most amateur mechanics will attempt on their Audi. It helps a lot to have someone who has "been in there" before offering guidance and drinking your best liquor. The timing belt should be replaced very 60,000 miles (or five years) to avoid breakage. Since it requires dismantling the front of the engine, there are several other parts that are routinely replaced at the same time to prevent future redundant labor. It is not a job for the squeamish, but an amateur can do it with some guidance and emotional support. Here is a list of what to replace (and why):
Often you can get the "basic" parts as a package deal from knowledgeable suppliers. Tools needed or at least very useful:
Procedure:
"Assembly is reverse of disassembly"... while assembling, double check everything you can as you go so less disassembly and reassembly is required. At each stage you should recheck all fasteners and installed components to prevent later grief. The engine will run without the front timing belt covers, although sometimes the rear cover will be bent forward and rub on the back of the cam pulley..
When reassembled, prior to timing belt cover, grill, and bumper installation, top up the coolant and run the engine for at least 10-15 minutes with some clean cardboard under it to check for leaks. Just for good measure, here is another description of how to do this, that I wrote before I realized I had already created this file: undo battery ground strap (always a good idea) take off the grills. loosen the alt, PS, and AC brackets and remove their belts. install new ones upon reassembly. remove the front covers (upper and lower) set up your 2084 and bust the crank bolt loose. remove the bolt, the pulley should come off. clean the crank threads, if you can, and clean the bolt threads. lock the cam pulley and loosen its bolt remove pulley, guard woodruff key carefully clean the bolt threads remove idler bolt, pull idler pulley steadily, smoothly forward - use makeshift tool if necessary. undo 3-4 bolts and remove back cover undo three bolts holding water pump - one is loose already, a PS pump bracket bolt. replace crank seal while you are in there. cam seal not so important, it's easy to get to anyway. clean front of block where water pump mounts (if you want to flush coolant, do thermostat, etc. do it now) grease new pump o-ring, place pump on block, finger tighten bolts, so it's free to swing. replace rear cover put cam pulley back on, finger tighten bolt install new idler pulley per Bentley with new timing belt wrapped around its pulley, slide harmonic balancer/puller assembly back in place turn cam and crank to TDC (do gently and slowly on interference engines, which are mostly the turbo versions) thread timing belt around pump, idler and cam pulley at this point you can lock the cam pulley and tighten its bolt there's a bit of fudging here - you don't really want to tighten everything up and discover you are off a tooth from TDC, but you gotta tighten things eventually! I would say, pull pump tight on timing belt, check for TDC, if it's all good, turn engine to appropriate place, lock crank and reinstall cleaned crank pulley bolt. Torque like hell - 450 ft lbs, is 150 pounds of weight on a 3 foot lever arm. This can break some 1/2" sockets, be careful. Now gently tighten the belt again with the water pump, when it is "just right" according to Bentley (easy to twist 90 degrees), tighten the bolts that are not the PS pump bracket bolt. at this point you can fill up with coolant if you lost a lot or flushed it. technically, the engine will run now, though I'd tighten that PS bracket bolt if you do try it. This is a good time for one more TDC check, and a careful rotation of the engine via crank pulley and big socket/ratchet. replace the covers, try to get every bolt as one or two might leak oil from the pump if they are loose or missing. install three new accessory belts, and tension, be sure to tighten all adjusting bolts. Try to look over everything again - missing bolts? leftovers? test fire engine. nothing? replace battery ground strap. test again. turn right off. if it seems ok, run til warm and top up coolant as it burps. replace grilles, and bumper if you took it off. cross your fingers that it all is working right, and go wash up. |
