jujuC6

I have been living with engine rattling when starting very cold since the end portion of last winter. I read the TBS for this problem and realized that this normal for a very brief moment and not for extended time. Unfortunately I have the extended rattling happening 3 out 5 on cold starts and I would say 2 out 5 starts if the engine is warm. At times the rattling go as long as 15 to 20 seconds then goes away. This thing has been annoying the hell out of me and not sure what it is. At work one of the cute interns was exiting with me and her IS300 was next to my car. She says, "Wow, nice car". I said, "thanks, you too". She starts her car and I waited for her to leave cuz I feared for my first impression. She did not leave right away so I went for it and started my car. Yep the noise struck again and her expression was something like, I take my compliments back. Seriously, has anyone had this problem and corrected it? I know that this is behavior is "normal" on cold start for a very short period but this is killing me. Any pointers as to what this is will be greatly appreciated, thank you.

spence341

So here's what I've got... Stretched timing chains. Are you sure it's coming from the cam shaft? I had a clacking sound from the drivers side lower bank. It clacked a couple of times before it got bad and the check engine light came on. Car ran rough (obviously since the timing was off). Pray this isn't your problem because it is a 30 hour $8000+ job. 104,000 miles.

jujuC6

I am not exactly 100% on what it is but based on the descriptions in the TBS is what makes me believe that it is the cam adjuster but now that you mention your situation I think it could be that too. My sound is from the front of the passenger side engine bank, possibly upper. I would hate to find out that I have a chain problem waiting to happen. VagCom returns nothing, there is no lights and the car runs fine. I guess I will have to eat a diagnosis fee and take her in. WOW, 8 XL Bills to get that fixed is no joke... Audi always has a way of making one feel special for purchasing one of their premium cars at some point or another. God forbid I end up in the timing chain situation but I would rather have them give me something for the car and use that towards a 3.0T. How long did you go with the sound before the chain went? Is there any way to adjust a tensioner or something?

spence341

From initial noise to cel was quick, only a couple of weeks. Once the chain stretches, it's done. If you don't replace the tensioner, you prematurely wear new chain. There are some short cuts that can save you some $$, but the labor is half the bill. They have to pull the engine and drop the tranny.

While they had mine out, they pulled the heads checked for carbon build up, made sure pistons looked fine and replaced the seals. I paid 1/2 the repair and since Audi paid the other half, they did the extra to make sure I wasn't in again soon.

If you have gone this long without throwing a check engine light, I would think it isn't the chains. For peace of mind, it's worth the 3-400 to diagnose.

A6Gary

My take is that your chain tensioner(s) is/are bad because the tensioner works off the oil pressure. If there is an oil leak in the tensioner (where it can activate it), it will make the chain effectively "longer" and the camshaft(s) out of time. That will make a lot of noise and affect the engine performance. Chains don't actually "stretch", they wear and can become loose, which affects the cam timimg, just like a defective tensioner.

jujuC6

My situation got worst as time went on, two weeks ago I changed my oil going from 5w40 to 0w40 Moly-Lubro and a day later the CEL came on and car started running like hell. I tried checking the obvious coil packs, spark plugs, changing low press fuel filter as it was in one of the codes, chaning the oil back to 5w40 and nothing. I gave up and took it to Audi. Audi confirmed that I have a failed tensioner which eventually stretched my chain. !@#$%^&*+!@#$%^&*!@#$%^&* Audi. They stabbed me in the heart with a 10K repair quote. However because I seemed like a nice guy they said, they would make me a good offer considering my problem if I get into new Audi. I was super BS about my car situation and about the slap in the face offer. I always like 2nd opinions on everything so I took the car to an Indy shop and they told me pretty much the same thing minus the "Sir, u dropped your soap" comment. The Indy shop is positive that they might be able to do the job without having to drop the engine or tranny for way less money. Questions, is it really possible to work on the timing stuff without dropping anything? It seems like there is barely any room for hands and even less for tools. While inspecting the plugs I noticed a little bit of oil on some of them, can my timing issue cause this or do I have more things going on like bad valve cover gaskets? I will be contacting AoA to see what they say about all this but given that chains are supposed to be maintenance free shouldn't Audi be somewhat be responsible for this common problem?

A6Gary

Bummer. I don't see how you can "stretch" a chain because it is all metal with round metalic pins that join each section. If the chain really stretched, it would break becuase you would have to stress the steel beyond its yield strength. With a failed tensioner, the chain will become effectively longer becasue the tension is reduced/eliminated, and slack develops. This slack then causes the engine to run out of time as the chain rotates around the camshafts, crankshaft, and idlers, potentially causing a piston to strike a valve. Since there are four chains driving the camshafts off the crank, the faulty tensioner could be behind the outer–most chain, which would require to remove everything in front of the faulty tensioner to access. Given the engine setup, I don't see how you could do this repair w/o removing the engine from the engine bay.

freshfrompacificrim

How would one diagnose this? I have no rattling but am scared to bear such an expense after the warranty expires

jujuC6

It all started with seldom and short period of diesel engine like sound coming from the affected side of the engine after starting in very cold temps. With time the occurrences became more frequent at any temperatures and went from a few seconds to the entire time I warmed the engine, once driving off the sound went away. I consulted with Audi and they said that this sound is normal in cold starts for a few seconds but I now know that it is not OK. The problem with this is that once it happens then is too late and one better start saving if one is out of warranty like me.

jujuC6

Hi everyone, a year ago around Christmas I had this chain rattling problem which the indy shop I took the car to was able to fix the problem without removing my engine. Sorry for not updating this post after resolving my issue but yeah it was the upper passenger chain tensioner. The guys at Audi told me that the upper tensioners are the more common and out of the two upper the upper passenger is the more common problem. A year later my problem has returned but this time as a more subtle extended diesel engine like sound compared to last time which was much louder. I listened with a car stethoscope and determined that the sound was originating from the upper passenger side cam tensioner again. I took the car back to them and they confirmed that the upper passenger side cam tensioner they replaced had failed again. They took out the tensioner today and told me that for some reason the tensioner had become lazy and did not want to open up all the way. To my luck which does not happen often enough the indy shop warranties all their work for 36months and was covered. Just wanted to share the bad and good news.