Rattle noise for 1-2 seconds on cold start

[Lethal1ty]

Hey guys

I have a Audi A4, 2005 B7

When from a cold start I get this annoying startup rattle for 1-2 seconds then it's gone. Engine is very quiet after this initial rattle. Car drives fine etc.

As I am aware this is a widespread problem but nobody has a definitive answer to solve this.

I have been driving like this for 2 years now.

We had the engine open the other day and there is no indication of wear or anything. Engine looks super clean.

Here is a link. My engine sounds precisely like it: https://www.youtube.com/watch?v=mBxoPelQC9w


Any help would be very much appreciated.

Thanks

[brandonpham]

Cam chain ? Is it towards the rear of the head by the firewall?

[vce1232000]

Weak timing chain tensioner

[Ringworm]

My A4 2.0 just started to do the same thing. Did you find the cause? And I didn't know it was a widespread problem.

[robsilvr85]

Can chain follower

[Axis]

If it goes away after warm up, check the vacuum pump hose. If its the case jb weld that suck@

[Ringworm]

Noise didn't go completely away after it was run. While having the car in the shop for an oil change, I asked them to check and replace the HPFP cam follower. When I picked the car up I was told they didn't do the cam follower work with some nonsense about a new cam follower coming from Audi. O.K., maybe next time if I didn't do it myself first. From then on, I was getting this rattling noise. Today I was looking around the engine and I noticed that 2 of the HPFP mounting screws were loose and one of them was missing. Tightened up the two remaining screws and voila, rattling noise gone. I think the shop started the job and for whatever reason stopped and forgot to retighten the screws. No damage done, all the threads in the head are good. Lesson learned: the only person who really cares about your car is you! All that being said. does anyone know the part numbers for the long T-30 screws that hold the pump to the head?

[heateris]

does anyone know the part numbers for the long T-30 screws that hold the pump to the head?

https://www.ecstuning.com/Audi-B7_A4...Pump/ES471867/

[Ringworm]

That will work. Thanks.

[larry_-]

mine makes the same noise i never really did anything about it though since its only on a cold start, but i might try and get that fixed soon

In the comments on that video this guy says
"The camshaft adjustment is hydraulically actuated and controlled by the engine oil pressure. If the engine has been turned off for a long time, the oil pressure drops down and the oil partially flows back into the oil sump.
To ensure an efficient camshaftadjustment right after an engine cold start, the oil pressure inside the camshaftadjusters must be built up as fast as possible. During this time, a rattle or knocking noise may be noticeable.
This noise is normal at engine start and will last until the oil pressure is fully built up, which takes about 1-2 seconds.
Production Solution
Not applicable.
Service
Do not replace the Camshaft Tensioner(s) or Camshaft Adjuster(s) for a noise concern as described above.
Replacing the Camshaft Tensioner(s) or Camshaft Adjuster(s) will not eliminate this noise."

Not sure if he's right, but he might be

[KJack]

Lesson learned: the only person who really cares about your car is you!

So true! In the past, I've had a few WTF moments when I've noticed my car come back from repair shops with loose or missing hardware. Some of these gorillas are in a hurry to get the job done as quickly as possible and important steps get missed as a result.

[P1Racer]

I am starting to notice this happening on my car. Has anybody found a solution to this. Could replacing the oil pump chain or tensioner help build oil pressure faster?

[Ringsby4]

these are noisy engines,Wolfgang is hungry and noisy at first start-up here.
HPFP and rear cam chain are largely to blame.But explore,mention of loose HPFP screws=maybe mangled threads ! not nice
Don't stress you have to compare the rattles with others in known mechanical condition...then maybe stress lol
A good Audi indy mech would have the experience to nail it.
Quietest engine I ever had was a Saab V6, circa 2003,but then V6's are inherently smooth and therefore prob. quieter...

[Okedokey]

To the OP, given you have noise, an unknown follower condition and probably accelerated wear on the lobe given the loose bolts you found, I would strongly recommend checking and replacing that follower asap.

[Hockeydad1519]

Hey guys

I have a Audi A4, 2005 B7

When from a cold start I get this annoying startup rattle for 1-2 seconds then it's gone. Engine is very quiet after this initial rattle. Car drives fine etc.

As I am aware this is a widespread problem but nobody has a definitive answer to solve this.

I have been driving like this for 2 years now.

We had the engine open the other day and there is no indication of wear or anything. Engine looks super clean.

Here is a link. My engine sounds precisely like it: https://www.youtube.com/watch?v=mBxoPelQC9w


Any help would be very much appreciated.

Thanks

Mine does the same thing, I’m going to do the rear chain and adjuster and tensioner, shop quoted me 600 just for labor.

[B7TitaniumA4]

I got the same quote (I supplied parts) but then the worst happened, somebody must have tried to do the service prior to them and my bolt was stripped, quickly jumped to an 11 hour job to pull the cams. $1400 later I have piece of mind for another 100k miles 🤷🏻*♂️

[Diablogomez]

mine makes the same noise i never really did anything about it though since its only on a cold start, but i might try and get that fixed soon

In the comments on that video this guy says
"The camshaft adjustment is hydraulically actuated and controlled by the engine oil pressure. If the engine has been turned off for a long time, the oil pressure drops down and the oil partially flows back into the oil sump.
To ensure an efficient camshaftadjustment right after an engine cold start, the oil pressure inside the camshaftadjusters must be built up as fast as possible. During this time, a rattle or knocking noise may be noticeable.
This noise is normal at engine start and will last until the oil pressure is fully built up, which takes about 1-2 seconds.
Production Solution
Not applicable.
Service
Do not replace the Camshaft Tensioner(s) or Camshaft Adjuster(s) for a noise concern as described above.
Replacing the Camshaft Tensioner(s) or Camshaft Adjuster(s) will not eliminate this noise."

Not sure if he's right, but he might be

To me it sounds quite right, these engines tend to be quite noisy, even when they are on some people believe they are diesel, mines makes the same rattle, cam follower ok, tension of the chain checked with VCDS and it's ok too.

[Theiceman]

back from the dead thread .. that's the rear chain tensioner, has nothing to do with tension of the chain checked with vcds. ( which is not accurate anyway on such a short chain. )

its either the tensioner itself or the oil supply to it is bleeding down overnight.

[esandes]

I have the same cold start noise. What larry quoted makes sense. Diablogomez, i am glad it's not a cam chain tensioner problem.