Hi guys,

Let me preface my question by saying I don't know anything about cars. I have a 2001 A4 1.8, and starting this morning, I started hearing a strange sound when driving. It's like those old school Benzes sound when they're idling - loud and constant clicking/rattling. When I step on the gas, it gets louder and louder. Then while driving, every few seconds I'll feel something under my car and it'll jerk. The oil light is on, but I added 2 quarts last night. And the check engine light is on. Of course, I'll take my car in to a dealer to check it out, but I was wondering if anyone had any guesses as to what this could be. I don't feel comfortable driving because I feel resistance as I accelerate. Thanks in advance

 

what kind of oil are you running?

most likely sludge

 

The 1.8 is notorious for sludge, sounds like you've got a lot. The clicking could be lifters or the cam tensioner, but sludge is more likely. When I bought mine it had a little sludge, so i changed the oil every 1000 miles or so instead of at the regular interval. A bit expensive, but it got rid of the sludge in about 6 months. Another option would be seafoam, search and ye shall find.

 

Oh, so I just need to take it in for an oil change? That's it?

 

Well I wouldn't simplify it quite that much, but an oil change certainly couldn't hurt. Go outside, open the hood, and pull off the oil fill cap. If there's some nasty gunk on the underside of the cap, you've got sludge. That would also explain the diesel-like sound you're hearing. If thats the case you're going to have to clean the gunk out before your motor goes boom.

 

Thanks, CC. When you say I'm going to have to clean the gunk out, is that something I should try to do myself? Or I bring it in somewhere to have them do it? I'm guessing the latter

 

Well you can do like i did and change the oil ahead of the normal interval, but that takes a while. You could SeaFoam it (seach on YouTube), but i'm no expert on that. You're not gonna be able to take it to a garage and say "please clean my gunk", because its a progressive problem. I would say just change the oil every 1 or 2k miles for the next 6-8 months, you should be good to go

 

I just took a look, and I dont' think I saw any nasty gunk I wouldn't expect to be there. It was brown and semi-liquidy, not thick like I would expect "sludge" to be (though I don't really know what that is). One thing I did notice though last night when I added oil at the gas station, was when I picked up the oil fill cap, I got all this black power on my hands that had accumulated on the outside of the cap itself, like charcoal. But I guess that's normal?

 

Yeah the black powder is ok, thats just dirt lol. I'd be concerned about anything noticeable on the oil cap thats thicker than new oil. I'd suggest changing the oil every 1k for a while and see if the noise improves. If not, you may need to look into having some more serious work done

 

Alright, but I don't feel comfortable driving it so I'm gonna take it into the dealer to diagnose first thing in the morning. It's not just a sound I can ignore, but actually affects my driving. Then after they do whatever they do, I'll change the oil once a month I guess. Thanks for the advice, man