I can do a lot of body/interior work, but I'm a novice when it comes to the engine itself.

If anybody has any clues to where to start troubleshooting, it would be greatly appreciated. I have googled a bit but this seems like such a general problem, I dunno where to begin.

Maybe it's more of a "ticking"



Thanks a ton!

1999 Audi A4 Quattro 162k

 

side note: it has a bit of a tendency to leak oil. not very fast but it does. it was also a bit low when I checked it just after I shot the video, again, not super low but it needed about a half-quart.

 

That doesn't sound very good. Have you tried to narrow it down to a particular area in the engine bay? Front, back, driver or passenger side? Maybe try taking off the plastic engine covers to try and get a better feel for the location. Another thing you can do is touch a long handled screw driver to various points on the engine and hold the other end to your ear. You'll hear/feel the vibration change as you move it around the engine.

 

From the brief time I was staring at it, it sounded like it was the top and front of the engine. Just behind the hood latch near the top. I will take a closer look with a screwdriver though and report back

 

It could be the serpentine tensioner rattling or the bearing in the pulley has gone bad. Easy check is to loosen the belt and slip it off of one of the pulleys.

 

Okay after closer inspection it seems like it's coming from directly (and I mean DIRECTLY) under the coil pack. In fact if you told me the coil pack (or something just beneath it) was notorious for having something come loose, I would buy a replacement with 99% certainty it would fix the problem.

I took the screwdriver and held it on the pack and it was pretty "vibrationy". I held it to valve cover and various "top" points around the engine and felt nothing aside from the normal hum of an idling engine.

 

Directly beneath the coil pack is the power steering pump. Perhaps there is a failing bearing in the pump. Taking off the serpentine belt would allow you to see if the noise goes away with it disconnected and allow you to spin the pump by hand to feel if it is failing. You can remove the belt without moving the lock carrier.

 

so just remove the serp belt and see if it still rattles and see what happens when I spin the pump by hand?

is the belt hard to get back on by hand? (it looks like it would be without removing the lock carrier, especially on a 2.8)

 

That's where I would start. You don't actually have to remove the belt. Removing the tension and slipping it off of one of the pulleys will be enough. The tensioner is down low on the passenger side. There is a ~17mm (maybe 18mm) standoff that you can grab with a wrench to release the tension.

 

okay, I removed the belt (btw, holy **** is there not a lot of space to get a wrench in there) and started her up. The rattle was gone! Given that is has to be something the belt uses and the sound is coming from JUST under the coil pack, I think it's safe to say it's the power steering pump. One thing I didn't mention is a few weeks back I checked the power steering fluid and it was low. I refilled it but clearly that didn't make anything better (in fact it MAY have got worse, I hope I used the correct fluid - Pentosin CHF 11S).

Regardless, I think I'm green-lighting myself to purchase a new pump. My buddy says I also need a suction hose? He says they rot easily and get rock hard so I won't be able to use the old one.