John McNeilly

my first post here. I have a 2007 A4 2.0T with 101,400 miles. The car has been running fine . I went to start it two days ago it was 5 deg. outside. It fired right up and started to make noise ticking I was thinking it was cold and let it run as it ran for about 3 to 4 minutes it got louder to a diesel sound . I shut the car off and checked the oil it was fine. Started it back up let it run for another couple minutes and it locked up. i didn't have a oil light or any codes.
Towed it to the dealer and they said you are 1,400 miles out of warranty. They told me the cam seized in the head. I had the cam follower for the fuel pump 20k ago. at the dealer under warranty.
I was thinking it could be possible that the timing chain on the rear of the head broke? i wasn't there and didn't see it thorn apart. the noise came from the top rear of the head. i was looking into thats back there online maybe the plastic chain adjuster broke on start up?
Any help on this would be nice I am very mad I paid for a ex-warranty that lasted 35,000 miles for a extra 5,500.00 3 years ago. I still have 2 years to pay for this car.I thought the warranty was for the life of the loan for 5 years or 100k miles that i put on.

John McNeilly

The dealer put it back together for me at no charge. I am picking the car up with a wrecker today. I think I will look at the cam follower and see if it wore out in 20k. I watched a video on youtube of a bad cam follower and it sounded just like it. I am afraid it must have gone into the timing chain and locked up the motor. Time will tell. still any suggestions would be great.

John535is

Initial thoughts - cams do not seize unless no oil, no maintenance and you have been using it as a farm tractor. Assuming you haven't (have you!) then it sounds more like the cam chain tensioner or chain at the back of the head may have broken, which may have caused the cam to skip a tooth or even damage the cam sprocket, break the chain etc.

I would start with:
1. Check your cam follower is still intact
2. Remove valve cover and check your chain and tensioner have not tried to depart company.
3. Remove the front timing belt upper cover and check you still have a timing belt nice and tight.
4. Pull the spark plugs (to remove the compression) and see if you can turn the engine by hand. Without compression, you should be able to turn the engine with a socket on the front cam sprocket or somewhere around the timing belt. Watch if the rear chain is moving and rotating the cam sprocket and cam and the rear cam sprocket is not loose or grinding on the chain.
5. If it won't rotate by hand with the plugs removed, I would be looking at the chain and tensioner to be replaced.

Now the concern is if the engine ran with the timing out by more than a tooth, it 'may' have damaged the valves impacting on the cylinders. Without pulling the head, with the timing chain and timing all correct you could do a compression test before starting the engine.

All of the above you can do for no cost, then you can decide if you want to repair yourself or at least discuss the problem with a mechanic with some knowledge of the issue.

I hate hearing stories of people getting shafted by mechanics because they just don't have a clue and the mechanic (actually dealers are bad for this), just replacing everything and charging you more than the car is worth.

Continue the thread with what you find.

good luck

John McNeilly

Thanks for you response. I am going to try to fix it my self. I have a very good mechanical background. That is where I was going to start. my gut feeling is they changed the follower 15,000 miles ago. and the cam probably should have been replaces at they time. but they either didn't look at it or didn't care and pushed it out the door.

Dolamite

If the original camfollower didn't punch through then your intake cam should've been fine. My guess would be to look at the tensioner, which would have a direct effect on the chain and timing.

What oil were you running at the time this happened?

John McNeilly

i pulled it apart tonight. hpfp follower was a little marked up but not trashed. Well it looks like the cam did seize on one bearing location on the intake cam. The timing chain tried to turn the intake cam and striped the spline on the intake cam. I could turn the exhaust cam a little and the timing chain starts to turn but the cam didn't.
So I removed the cams cranked the motor over and all cam oil holes have oil. kind of strange that it would seize in the head with oil. It was very cold outside that morning. I run Castrol synthetic oil. I need a cam to put it back together. The top cam cradle is galled and the head is galled on one journal.
I also did a compression check and had 130 on all 4 cylinders. So i think the valves are ok. But the one cam bearing needs to be cleaned up a bit.

John McNeilly

In the pic with the cam sprocket you can see the metal filings as it tried to turn. In the other pics you can see the head galling on the bearing journal.
When I took the motor apart the timing chain had pressure on the chain adjuster. I was able to compress the tensioner with my hand pushing down. I have seen where you need a tool to compress it. I am kind of thinking the tensioner was weak? I don't know.
I do know that timing belt is going to be NO fun to get back on or Replace. I am thinking of trying to clean up the galling and replacing intake cam,timing belt,chain adjuster and roll the dice.
I should trade it in running. But I am so upside down.

Dolamite

Yeah that galling does look bad. A few cranks wouldn't do that though.

I think you said that you left it in idle? Somehow the oil pressure was starved. That's the only thing that would've done that, unless a freak mishap with timing, which highly isn't the case. Oil pump and pickup should be checked for blockages.

Don't know what temperatures you're in except you said it was cold. After getting things fixed I'd start using vw/audi approved 0w40 weight in the winter if you aren't already. 0w40 travels faster in colder startups, but remains a 40. I'm in Chicago with neg temps and use it without issue.

John McNeilly

I have a new cam coming. I bought the timing tools also. I cleaned up the galling on the head with a light sanding drum it was just in the middle. It will be a low spot there but hey if it doesn't work I will just have to replace the head. I am not afraid to do it . I just don't have the time this time of year.
I know the right way it should have been done but if I can squeeze by with a cam and new timing belt that will be fine with me. If it lasts a month it will last a year.I also think a couple back to back oil changes too. The 0w40 sounds good also. I think I was running the Castrol synthetic oil . might add some lucus oil treatment. has anyone found moly additive ??
when i was turning over the the motor doing compression tests it had oil right up to the head in seconds. I might have just gone over on the oil change and oil went to crap. It didn't look dirty in there. it was like 0 deg out when I started it with out windchill .
thanks for your help I will keep posting too.

Dolamite

Brave man you are. When you tested your engine it was probably in the garage. Have you seen oil in very cold weather?

It's pertinent to get a lower cold weight that'll still be a 40 in full temp. I don't think additives will help the case except for lube on the initial start after your cam install.

For other readers too, rather than letting a car sit and warm-up, it's best to idle for ten seconds or so and start driving around the block or where ever as if you had a full cup of coffee in the car and don't want to spill. You want to get that pump moving oil through the engine as well as heat up, yet you don't want to be running full bore stressing all those cold parts. It's a give and take.

Keep us posted man.