|Tech Article Title
the Timing Belt (A4 1.8t)
After reading the forums for the last few months, I decided that my 66k miles was just the right time to change the timing belt, water pump, thermostat, and belts. I also added the APR snub mount since I was gonna be there anyway. I looked through the forums and couldn't really find a good detailed run through on the whole procedure, just the front bumper removal. At first this discouraged me, but I have done timing belts before, as well as clutches, etc. I sent off for the Bentley CD and ordered the parts from
www.germanautoparts.com . I figure Dave saved me something like $100 in parts over my local dealer. He was great to deal with, the pricing excellent, and all parts arrived in good time to get started Friday night. I have an early '99, so it needed an updated timing belt tensioner, I'll get to that later. Sorry I don't have any pics, I didn't have a camera handy, and it would have gotten all greasy anyway. I'll try to describe as best as I can.
- Torx T20, T25, T27, T30, and T45 ( I bought a set plus the T45 for about $20)
- 5mm, 6mm, 7mm hex wrenches (it really helps to have two 7mm's for some parts)
- 10mm, 13mm, 14mm, 17mm sockets and wrench (again, I would recommend a u-joint
for some bolts, about $6)
- Standard screwdriver
- Vice grips or pliers, etc
- Bentley CD (optional but very helpful, and not just for this job)
1 gallon of new coolant $15
- Thermostat and O-ring $18
- Water pump impeller and gasket $39
- Serpentine belt $30 (had to buy at dealer, ouch)
- A/C pump belt $10
- Timing belt and updated tensioner kit $130
- I also replaced the motor snub mount with the new piece from APR $50
The job took my brother in law and me about 8 hours. We didn't hurry, but we didn't slouch, either.
The first thing to do is to get the car up on Jack stands. This makes everything easer to get at and that much closer to your comfortable working height. Now disconnect the battery. Next get ready to pull off the bumper. APR sent an instruction sheet on how to do this; it is really easy (you can download a copy at
www.goapr.com/support/snub_mount.pdf). After taking off the belly pan, you literally just take out two bolts and push the bumper down, then it pulls right off. After detaching all the hoses, electrics, etc, unscrew all the screws holding the radiator assembly to the car. There are seven T45 bolts that hold the radiator to the car frame, these need to come out too. After all is unscrewed, the radiator section slides forward enough to get to the motor mount. If this is as far as you are going, great. To get to this point shouldn't take more than 45 minutes. The snub mount was kind of a pain to get off, I ended up cutting it with a razor. The new one didn't go on real easy, either. There is a rib inside the mount that is tough to get to clear the mounting spindle on the radiator. I suggest heating the new snub mount in the sun or with a hair dryer, it will make things much easier. Once it's on, you just reverse your procedure. No problem. I was going further, though.
To pull the radiator assembly off, you have to disconnect all the lights, the horns, the three radiator hoses, the intercooler shrouding, the hood release pull, and about four other electrical connections. Make sure you have drained your coolant before you do this. Even after all this, the assembly does not fully disengage. You have to leave the AC ducting on unless you really want to screw things up ( you don't ) and there is one wire to the radiator fan that I couldn't see a way to disconnect completely. You do have enough slack to kind of pull the whole piece out of the way enough to get into the front of the engine. I rested the assembly on a couple of chairs. You have to put it on something, it will not reach the floor without bending/breaking hoses or wires. It really helped having an extra set of hands here, too. My brother in law was around and his help proved invaluable. I can't say it would have been impossible without him, but it would have been a real pita. Anyway, once the radiator assembly is out of the way, you can start taking the front of the motor apart. The first thing is the fan. Easy. Then the serpentine belt comes off. There is a tensioner near the top of the engine that you clamp with vice grips or some such tool and release tension on the belt enough to get it off the pulleys. I really recommend replacing the belt while you are in this far, it ran about $25. After the serpentine comes off, there is a lower belt for the A/C. I replaced it, too. It has a different style tensioner, but it is pretty easy to get off. Now we are getting down to it.
The next piece to come off is the water pump pulley. It is held in place by three hex bolts, and there is no easy way to brace the pulley from spinning, so you will need two hex wrenches. One to break the bolts loose, one to hold the pulley in place. It is easy if you have two wrenches. I had to go to the auto parts store to get a second. The next pulley to come off is the big vibration damper on the lower part of the engine. This is the pulley with two tracks for the two belts. It has a 17mm bolt through the center and four hex bolts around the perimeter. This pulley is also attached to the crankshaft gear behind the timing belt cover, so it definitely needs to come off. You need to crank one way with the 17mm socket wrench while loosening the four hex bolts with the hex drive. Pretty easy if you have someone helping you, and probably easy enough alone. Now that you can pull the timing belt covers off, do so. The upper is just help in place by to tension clips. There are two hoses routed across the front of it, I just left them in place. The lower cover is held in place by three or four bolts, hex and standard 10mm heads. Pull these out and the cover comes right off revealing the timing belt, tensioner, and assorted pulleys and wheels. The camshaft wheel is at top and has a mark for Top Dead Center. The crankshaft wheel had no mark that I could see. The old style tensioner has three main pieces, all connected. I had to remove it to get the timing belt off. IMPORTANT!!! Make sure you make a mark on the timing belt and on both wheels. I used TDC on the top wheel and just picked a tooth on the bottom wheel. Mark both the wheel and the belt!! Each wheel will have one mark and the belt will have two. This is important for replacing the belt. IMPORTANT!!! Make sure you do not move either the crank or the camshaft wheels while the belt is off. You will have the joy of doing this whole process again if you do!! The tensioner has a pulley on it that needs to come off. I found it easiest to put the tensioner back on the block to break the bolt loose. Make sure you get this off, you will need it for reassembly. Anyway, once the tensioner and belt are off, give the area a basic cleaning. Next to come off is the third toothed wheel in the set. It is between the cam and crank to the right. It has a large 25mm (guess) bolt holding it in place. It must come off to get to the water pump. If you are not replacing the pump, don't sweat it. Skip ahead to the part where I put the timing belt back on. Otherwise, read on. I was able to break the large bolt loose with average pressure using a set of vise grips. I wedged a hex wrench between the wheel and the engine block and gave it a good wrench. The bolt came off pretty easy. You have to pull the wheel off evenly or it won't come. I used a pair of hex wrenches in the holes on the wheel and it worked pretty well. Now you can get to the eight bolts holding the water pump in place (NOTE: I did not replace the whole water pump, simply the impeller. The rest of the housing has no moving parts and is a real bitch to get off.). The pump impeller comes off easily, along with some more coolant, so be ready. There is a metal and rubber gasket that stayed on the housing, and it kind of looks like it is permanent. It is NOT. Make sure you remove and replace this gasket when you put the new impeller on. My replacement gasket was a standard paper gasket, but seems to work fine. I also replaced the thermostat and O-ring. You have to pull the heater hose off the bottom of the pump to get to it, but it's only two bolts and as long as you have a universal joint for your socket wrench, you should be fine.
All right, you have everything as far apart as it gets. Now to put it back together. First the thermostat. The thermostat goes in first, then the o-ring. Get it right or you will be doing it again. Hopefully you don't realize it's wrong because you have a leak and you overheat. Nevermind. Once the thermostat is in, put the impeller gasket in place (there is a bolt that sticks out from the back of the pump, so this is easy) and position the impeller. Finger tighten all eight bolts and one nut on the impeller. You have to make sure to do this next part right, or you may get a leak through your gasket because it got pinched. There are four bolts and one nut on the bottom half of the impeller and four bolts on the top half. Tighten the five on the bottom like you put on a car tire, kind of gradually and by alternating sides. Do not tighten any one bolt all the way until all nine are secure. Then go back and give them the once over. You get the idea. Reinstall the third toothed wheel for the timing belt at this point.
Bolt the new timing belt tensioner to the block and install the pulley you pulled off the old tensioner. DO NOT PULL THE PIN ON THE TENSIONER!! If you do, you may as well buy a new one. Now it's time to put the new belt on. Remember the marks on the old belt? Count the number of teeth in between these marks and mark the exact number of teeth on the new belt. This is very important. If you don't get the same teeth, the timing on the car will be wrong and you will need to redo this whole process. When you have the new belt marked, align it on the cam and crank wheels. This can be difficult, and you may need to stretch the belt a bit. This is another place that it is good to have two people. You must also be careful not to jar the cam or crank in this phase. Once you have the belt aligned on the wheels, bolt on the new tensioner wheel and tighten it down ( you have to remove the
aluminum stud from the block to do this). Double check your marks and make sure everything is correct before pulling the pin on the tensioner. Voila! New tensioner and belt are in. That is the end of the hard part.
Now put everything back together in the order you removed it, paying special attention to the radiator hoses and electrical connections. Once you get the radiator assembly on, but before the bumper is on is a good time to put coolant in the car, reattach the battery and see if everything is working. If you are satisfied with your work, put the bumper and belly pan back on and go for a test drive. Don't go too far initially, in case a coolant hose comes loose or something else. You want to be able to limp or push the car home (let's hope not!!).
That's about it. There were no major snags for me, I think it must be the german engineering at it's best. Everything was obvious, though I did double check on the Bentley CD from time to time to make sure it was right. If you take your time and stop for a drink and a snack once in a while, anybody with a fair amount of wrenching skill can do this in the garage.