Strange noise on startup after replacing timing chain tensioner (E39 540i)

[S16]

So I replaced the timing chain tensioner on my M62TU probably about 3 months ago, and the car started making a fairly loud noise from the tensioner area after I changed it.

The tensioner was installed correctly as far as I'm aware, as I was sure to compare them and confirm the new tensioner was going in the right way. I have not removed it since this noise started happening, and have not tried to re-install the old tensioner to see if the noise would persist.

The noise only happens for about 2 minutes when you start the car, before it stops completely and the engine runs quietly as it should. The best way I could describe the noise is like air being sucked in to something, creating quite a loud noise. When I got an opinion from a friend, they described the noise as an intense whirring and not a sucking noise.

I have recorded a video of it happening, the noise stops towards the end of the clip at 1:42.

This happened every time I start the car cold and always stops after about 1-2 minutes.

Any feedback is appreciated, as it is slightly disconcerting although it seems inconsequential.

Cheers

https://www.youtube.com/watch?v=CfEf-qLSj3k

[JimLev]

Sounds like it's your secondary air pump to me, bad bearings.

[S16]

Started happening straight after the tensioner change, leading me to believe its related to that?

[JimLev]

Just a coincidence.

[TheProdistini]

I have to agree it sounds like the secondary air pump, you're sure the hose coming from it didn't come off?

[geargrinder]

I hear the hissing/sucking, gonna agree mighta knocked a connection off or something.

You have a lot of exhaust noise - is that normal / do you have muffler delete or something? If not, then if the SAI hardpipes are loose/leaking then you can get exhaust noise leaks at the front of the motor. BTDT.

Separately it does also sound like there's some valve clatter? When you hold the phone up to the valve cover? I imagine that's what you were hoping to attend to w/ the tensioner change?

I'm beginning to believe the widely promoted tensioner replacement is mostly a waste of time and money. So many get changed in hopes of addressing worn guides and VANOS seals I think, to no avail. But there were those early threads from 10yrs ago with guys changing them and now everybody tries it 'just in case it helps'.

[kerryb]

Jim - the secondary air pump, can cleaning out the valve help, or need to get new pump? Have the same noise, goes away 2 min after cold startup.

[JimLev]

If the squealing noise is coming from the pump cleaning the valve won't stop it.
However, if the valve is packed with carbon and not closing that allows exhaust to get back into the pump bearing which causes them to fail.
I clean my valve every 3-4 years, (153K on car now) and still have the original sec air pump.

[kerryb]

carb cleaner spray, brakkleen ok to use to clean the valve?

[XAlt]

carb cleaner spray, brakkleen ok to use to clean the valve?

I brake cleaner, it would really suck if it threw a CEL and force me to delete it. Fan clutch + lightweight flywheel + GruppeM HAI + loud SAP = noise = good

[S16]

I hear the hissing/sucking, gonna agree mighta knocked a connection off or something.

You have a lot of exhaust noise - is that normal / do you have muffler delete or something? If not, then if the SAI hardpipes are loose/leaking then you can get exhaust noise leaks at the front of the motor. BTDT.

Separately it does also sound like there's some valve clatter? When you hold the phone up to the valve cover? I imagine that's what you were hoping to attend to w/ the tensioner change?

I'm beginning to believe the widely promoted tensioner replacement is mostly a waste of time and money. So many get changed in hopes of addressing worn guides and VANOS seals I think, to no avail. But there were those early threads from 10yrs ago with guys changing them and now everybody tries it 'just in case it helps'.

Indeed the purpose of the tensioner change was to address what I now hope is a bit of VANOS noise, as the change made no difference. I do have a full 2.5 inch twin exhaust with high flow cats and one muffler at the rear, so the car is reasonably loud.

Cheers for the input everyone, might have to do some proper digging around when I get a spare minute over the next few days.

[kerryb]

couldn't get to the 10mm bolts on the valve, if someone has a trick to get to them, really would appreciate the tip. my vacuum hose to the valve was worn at the end, so i cut the bad part off, had enough hose to reconnect properly. will monitor next few starts see if that helps..

[geargrinder]

Waiting is fine in this case but just for reference, if you have INPA I'm pretty sure you can force trigger the SAP for diagnostics like this when the DME won't fire it after the car has been started a couple times.

[whiteghost1]

I'm beginning to believe the widely promoted tensioner replacement is mostly a waste of time and money. So many get changed in hopes of addressing worn guides and VANOS seals I think, to no avail. But there were those early threads from 10yrs ago with guys changing them and now everybody tries it 'just in case it helps'.

I agree. I am one of those statistics but in my case I changed the tensioner as a preventative measure based on all of those early threads. My engine was quiet when I replaced the tensioner with a new one. 3 weeks later my guides blew out and failed and had to do the guide job (along with Vanos). After my experience I am of the opinion that a new tensioner exponentially accelerated the guide failure. I hope those reading this will think twice about replacing the tensioner, especially if your engine is silent at start up.

[S16]

Good news, the pipe underneath the airbox going to the SAP was not attached properly. Easy fix cheers for all the feedback!

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[geargrinder]

Ha. Easy. Those stupid plastic pipes suck so hopefully it's not on the way out but its not a massive big deal if it is...

[S16]

Ha. Easy. Those stupid plastic pipes suck so hopefully it's not on the way out but its not a massive big deal if it is...

It seems to be a bit "how ya goin" but hasn't come off again yet so hopefully all is well.

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