Need Help! 1998 A6 quattro 2.8l
 

After a run of bad luck (nail in motorcycle tire, busted out truck window, and expensive vet bill for sick dog) I have had some good luck. An old timer that lives not too far from me was giving away some vehicles, yes giving away. Now, I am far from a mechanic but I figured if I can get them running rather cheaply great! If not I can always make a couple bucks selling them as parts vehicles. I managed to grab a 98 isuzu trooper (needs starter), a 88 suzuki samurai (rats destroyed wiring and is a bit of a hoopty), and a 98 Audi A6 with 133k miles and is the car in question.

I was told by the previous owner that it ran when it was parked but made a horrible noise that he suspected was the water pump. The previous owner informed me that the car had been sitting for about a year (rat poop on all of the engine plastics were a pretty good indication of this) but should fire right up with a new battery (I didn't really believe him). I threw the battery on a trickle charger for a couple days and sure enough it fired right up (I was tickled pink). He wasn't joking about the noise, it sounded like a rock tumbler at a gravel yard. I've never done a water pump on any vehicle but with the help of this forum and extensive youtubing I mustered up the courage to do this job.

Holy snopes was the front bumper a pain to get off, but I managed it. Two things really concerned me when I was pulling the front apart.
1. the bottom cover, the one under the car, was covered in oil. Not fresh oil but the car had been sitting for a year. I noticed over night it does have a slow leak. In a 24 hour period it left about a 1/2 inch "puddle" on my garage floor. I checked the oil level cold and it still had plenty of oil. The amount of oil that had to be dropped on the bottom cover to make it look the way it did had to be a significant amount, so I'm thinking/hoping that the oil is from an old issue that has been fixed.
2. When I drained the coolant maybe 12-18oz of fluid came out, yeah like a coffee cups worth. Maybe another 8oz came out when I pulled the lower radiator hose and the coolant reservoir was empty.

When I got to the water pump, sure enough it was completely destroyed, the roller moved up and down about 1/4" and there was metal shaving all over in there. I cleaned it really well and did the water pump, timing belt and tensioner, and thermostat while I was in there. I noticed someone had marked top dead center on the bottom pulley? and marked a white spot on a tooth of each cam pulley that corresponded with a white spot on the timing covers (sorry if I am mucking up the terminology, not a mechanic). I thought maybe this means someone else has been in here and done some work? And maybe the work was a result of all that oil on the bottom cover.

I bought a ton of distilled water in order to flush the system. On the first startup I really messed up and forgot to screw in the two hoses that circulate the transmission fluid. What a mess that made... so now I need to service the transmission too... sigh. After cleaning the mess I figured I didn't lose so much fluid the transmission would be dry and I wont be driving it so its probably fine for now. On the second startup I noticed it was still making a rather loud rattling noise. I shut it down immediately and consulted the internet. I decided maybe it was the serpentine belt, so I pulled it off and started it up. Sure enough the rattling went away. I made sure all the accessory pulleys were tight and reinstalled the serpentine belt and the noise persisted (maybe the tensioner needs replaced?). Relieved that I hadn't screwed up the timing belt/water pump job I continued on with coolant system flushes.

As I brought the vehicle to temperature it began to smoke around the engine (white color smoke) and I freaked out jumped in the car, looked at the temp gauges, and shut it off. I made three observations.
1. Oil temp was still rather low (between the cold and first mark up from it)
2. Coolant temp was in normal range (just shy of half way between Cold and Hot)
3. When I crawled underneath the car there was what I initially assumed was oil but turned out to be distilled water on both exhaust pipes dripping down behind the transmission fluid tank.

I figured the smoke must be the water cooking off on the exhaust pipes so I continued with my flushing. I carefully kept an eye on the coolant temp and oil temp and they never got out of normal operating range (coolant not above half way mark and oil not above the 1/4 mark). I did four flushes and then I pulled everything apart to get back to the water pump to see if it was leaking. It was bone dry. Finally, I put the new coolant in and bled the system at the heater core hose ( I couldn't find a bleeder on the top radiator hose as some directions had indicated there would be). As I bled the system I noticed a substantial puddle of coolant had formed on the ground under the car. It was leaking more coolant than I would be comfortable driving the vehicle with. Wiped up the coolant and the leak seems to have stopped so its only leaking when its at running temp.

Now that I have written a short novel here is my dilemma. I was thinking about keeping the car as a commuter instead of riding my motorcycle every day (winters are cold in Northern Nevada) or driving my truck that gets terrible diesel mileage. However, with this coolant issue, that I'm not sure how to fix, I'm thinking I might just cut my losses and see what someone will give me for it as is. I'm about $270 into it after the water pump job and title transfer. I think I could probably get about 500-800 for it?

Problems
1. Mysterious coolant leak (and small oil leak)
2. Rattling component run by the serpentine belt (maybe tensioner)
3. Replenishing transmission fluid/servicing transmission
4. Forgot to mention, I simply placed my hand on the vacuum line that goes to the vacuum reservoir... it broke DOUGH! *headslap*
5. Gonna need tires as the ones on them are weather checked and not much tread left

Solutions/Questions
1A. Head gasket leak is causing the coolant leak? I haven't seen any other signs of a head gasket leak. Oil looks fine, no white smoke out of the tail pipe, seems to be running fine aside from the smoking and despite the vacuum leak. What else should I be looking for if it needs a head gasket? I really hope its not the head gasket as it seems a bit beyond my skillset.
1B. Auxiliary pump is leaking? I couldn't figure out if the 2.8l has an aux pump? Seems to be conflicting data on the forums. Do some have one and not others?
1C. Coolant temp gauge at the back of the engine is leaking? Is this expensive? I guess I should just price it out and do it?
1D. Heater core hose is leaking where it connects to the block?
1E. Am I missing anything else?
1F. Is it worth the $$ to try all of these solutions on a car that is probably only worth $1500?

2A. Aside from the annoying rattling whats the danger in not replacing the serpentine belt tensioner? Is there anything else that could be rattling or is it most likely the tensioner?

3A. I really dont have access to a lift, can I do the transmission service on jack stands?
3B. Can I just replace the fluid I lost or do I need to drop the pan? Also, does it have to be the expensive German ATF or can I skimp and get something cheaper?

4A. The hose that runs to the vacuum reservoir (three blue bubble thingies in the driver side front wheel well) was a rubber hose that was connected to a hard plastic hose that was connected to the reservoir. Can I just plumb in another rubber hose with a connector and run that to the vacuum reservoir or do I need to find another hard plastic hose?
4B. If I keep the car I'll probably do all the vacuum lines, do I need to expect the fasteners connecting all of the lines will need replacing or just the rubber hoses?

5. Tires... Sigh

Again sorry for the short story but I wanted to give as much detail as possible in an effort to help me diagnose the issues. Thank you for reading my book and thank you for any advice you can provide. *cross posted in Audiworld*

I would sell it if I were you. Audi are known for oil leaks from cam seals at either end of the heads and from the cam chain tensioner gaskets. The cam chain gasket can be hard enough job on mechanical people and if your not fairly experienced i wouldnt even attempt it. As for the the coolant leak if its leaking where the heater core hose hooks into the plastic housing connecting to the engine block that is pretty common as well. The o-ring goes bad and it starts leaking down the back side of the engine.. I wouldnt replace just the o-ring though get whole new housing with new o-rings to be on the safe side. rattling noise you would have to turn everything you can by hand with the belt off and take your best guess as to which item is the noise maker there.. The tensioner would be your cheapest and easiest thing to start with off course rather then tackling the AC compressor or power steering pump and so on. Audi makes good cars and im sure when they are new the first 5 to 10 yrs are great for owners however buying them old and used can be a serious drain on your time and money trying to keep them road worthy... I have a 99 A4 quattro with 1.8 turbo and auto trans as well as a 01 A6 quattro 2.7 twin turbo with manual trans and they both have needed alot of work and money to keep them some what decent. The quattros are great for winter time driving and all but when it comes down to it you need to be fairly mechanical and like working on cars to keep up with the problems Audi always seem to have. The only reason i got the ones i have is the A4 i bought for 700 and the A6 i got for 1500 bucks, cheap starting point but with all i have had to do to them and the fact that the parts are almost always pricey for these things its just not worth it for most people to bother with them... I posted recently on here about a problem with my brakes, every time i hit the brake i get a beeping noise from the dash. And the abs and esp light come on when i turn the headlights on for some reason lol. After more then 300 people had read my post not a 1 of them had any advise to offer, i checked things out replaced brake light switch scanned for abs codes and in the end since i couldnt get the problem at hand fixed i took the instrument cluster from the dash and took it apart to remove the annoying speaker from it so at least it wouldnt beep every time i hit the brake pedal lol.. Not a good fix but oh well some times you do what you gotta do. If you do decide to keep the car and work out the issues best of luck to you and i will do my best to help answer some of your question but keep in mind i dont have a Audi with your exact engine but my 2.7 is fairly similar.