banner

Repairs P.4

Audi A4 1.8t Repairs P.4

Preventative Maintenance #017 : AEB Timing belt, water pump, drive belts, seals, and tensioners.

The Audi AEB (97--? 1.8l turbo) engine is of the "interference" design. Which means that if the timing belt snaps due to the age or anything else, the pistons crash into the valves and bend them. This is exactly what happened to the previous owner of my engine at 77k miles. Needless to say, I made sure to get this stuff replaced a bit early. There was also an early design for the timing belt tensioner that apparently accelerated wear.

The water pump belt is not self adjusting and mine was right at the failure point. It was severely cracked and the pulleys could spin without moving the belt. The drive belts were also cracked and needed replacing. My thermostat had been stuck open since winter and the front crank seal was leaking. I replaced all of that cleaning as much as I could along the way.

One of the most daunting parts of this job was getting the crank bolt off. M___ and J____ wedged a couple of pieces of scrap aluminum between the teeth in the crank pulley and the plate that the snub bracket bolts to. With the 5ft pipe it came right off. The wedge trick worked to get it back on again also. Thanks guys!!

ECS mislabeled the seals they sent me in their timing belt kit. Neither of the seals they sent me were the right part number but the one labeled "cam seal" fit the crank.

The A/C belt is also not self adjusting so that will have to be tightened eventually.

timing belt

Taking the front of the car off I dropped the bumper >_<! The plastic hose fitting to the headlight washers broke. That's ok though as I was planning on making an intercooler sprayer out of it anyway. It's pretty much all set except I need a spray nozzle for the hose.

If your coolant was anything like mine I highly suggest a full coolant flush (it is also quite easy to hose out the radiator while it's out of the car).

To get the coolant hoses off (and on) the radiator pull up on the metal spring clip, then ~carefully~ use a hammer and a punch/screw driver to knock it off. If you're stronger than me pull really hard. Cleaning both sides helps putting them back together. There is an inner sleeve with a big o ring behind it inside the radiator hoses. Make sure they're on all of the way!

Things that I wish that I'd had when I did this project:

not-obvious tools that you must have:

Repair #018 : Rear coolant flange, CTS, and o-rings

coolant flange

From what I've read on the forums this is a very common failure point and after having done it I can see why. There is a how to on Audiworld for replacing the flange.

The coolant flange is a plastic coupling bolted to the back of the block. It has a hole for the CTS, another hole that takes a plug on my model, a flange for a crossover pipe, and a fitting for the heater core hose. The common failure points seem to be the o-rings (it has 4) and the flange itself cracking at the CTS mount. I joyfully experienced both issues.

flange

Parts needed (for a 97 A4 1.8T Quattro):

The problem that is that the flange itself is poorly designed. If it were metal with beaded pipe ends for the hoses it would probably not fail until much later and would be much easier to fix. The flange bends, breaks, and generally disforms leading to leaks even when new.

The Meyle flange didn't include new o-rings and neither did the new sensor. That royally pissed me off since 50% of the time those are the failure points. I failed to find any correctly sized o-rings locally. J____ was in a distant locale where there is a Northern Tool store, there he found an assortment of 400 metric o-rings for 15$.

I had this thing out no less than 8 times trying different combinations of o-rings, sealant, glue, and everything else to try to get the coolant crossover pipe to flange junction to stop leaking.

The flange side started to leak also by the later revisions. What I did about that was to file down the brass inserts shown above so that they sat flush with the head side of the flange, to draw it in closer when you tighten it down. Second was to use a larger diameter o ring (3.5 mm i think) from the assortment from Northern Tool.

At the pipe junction side of the flange I finally used a smaller o-ring in the inner step of the flange along with the stock one at the rear step and some fresh rtv. Not sure what actually sealed it but it finally worked. They fixed this problem on the B6 with what I had concluded earlier to be the obvious fix. A beaded pipe end to clamp an extension hose to the metal pipe with, like every other manufacturer, and thats yet another good argument for upgrading to a B6 should you get the chance lol. It looks to me like the B6 flange will fit but I need one to test it out. All you'd have to do to make the pipe side fit is cut the flange off and put a hose between them

flange

B6 flange photo mercilessly stolen from Audizine forums for the sake of science. Even this superior flange has experienced the head side o-ring failure. You wouldn't necessarily need a new flange to fix this, you could just clean it up and stick a new o-ring in there.

Repair #019 : Oil pan gasket and front subframe mounts.

I have yet to own a car that this didn't eventually leak on. On the A4 you need to be able to remove the front subframe to get it out. While it is out you can replace the subframe mounts with new or fill them with urethane or a chewy nugat filling.

be sure to clean the mating surfaces well. Check to see if there are any leaks coming from above like the front crank seal or the rear main seal. The front crank seal and cam seal can be done with a timing belt, rear main seal with a clutch job.

Back to repairs page 1

Contact Us | ©Team skittle racing