Just curious what all the noises are...

[scorch07]

So we all know the 2.5 makes an interesting collection of sounds, particularly at start up, but I'm curious if we actually know what the various components are.

#1 - The whine - I'm kind of assuming this might be the alternator or something else on the belt? I hear it in pretty much every video I've seen of a 2.5

#2 - Clicking - There's a clicking that seems to come from somewhere around the front of the motor. Behind the intake mani perhaps. I'm assuming it's just the valves/cams or maybe the timing chain but I'm not sure. Anyone know for sure?

#3 - Blowing noise on startup - It doesn't seem to do this one very long but I've heard a pretty significant flow of air from somewhere. Like a vacuum cleaner minus the actual pump noise. I've heard an air pump mentioned before so I guess it's that but, again, not sure. Am I correct in thinking that's something to do with SAI?

I know this has all probably been covered at some point or another but searching proved surprisingly unfruitful. Just interested in learning more about this engine. Feel free to throw any other weird noises out there.

[Dronks]

So we all know the 2.5 makes an interesting collection of sounds, particularly at start up, but I'm curious if we actually know what the various components are.

#1 - The whine - I'm kind of assuming this might be the alternator or something else on the belt? I hear it in pretty much every video I've seen of a 2.5

#2 - Clicking - There's a clicking that seems to come from somewhere around the front of the motor. Behind the intake mani perhaps. I'm assuming it's just the valves/cams or maybe the timing chain but I'm not sure. Anyone know for sure?

#3 - Blowing noise on startup - It doesn't seem to do this one very long but I've heard a pretty significant flow of air from somewhere. Like a vacuum cleaner minus the actual pump noise. I've heard an air pump mentioned before so I guess it's that but, again, not sure. Am I correct in thinking that's something to do with SAI?

I know this has all probably been covered at some point or another but searching proved surprisingly unfruitful. Just interested in learning more about this engine. Feel free to throw any other weird noises out there.

#1. The whine is completely normal but I have no idea what it's from. Something on the belts or perhaps the timing chain guides?

#2. If it's a constant ticking sound it's probably just normal valve train noise.

#3. That's the air pump. It injects fresh air into the exhaust to "cheat" on emissions and help the Cat do it's job among other things.

[rags2riches]

Let's not forget the ABS system check sound. This is a knocking sound that comes from the passenger side rear of the car. I notice it from time to time and it seems to happen randomly. It's been doing it since mile 0.
I also noticed an electric buzzing sound when I open my drivers side door. Not sure what that is.

[scorch07]

Let's not forget the ABS system check sound. This is a knocking sound that comes from the passenger side rear of the car. I notice it from time to time and it seems to happen randomly. It's been doing it since mile 0.
I also noticed an electric buzzing sound when I open my drivers side door. Not sure what that is.

I know the buzzing sound is the fuel pump. It pressurizes the system to be ready when you go to crank it. A sort of "pre-prime" I suppose.

I just remembered another one. A clicking right after I turn it off. Seems to come from the throttle body (so I suppose it's quite possible it's the throttle actuating).

[Dronks]

I know the buzzing sound is the fuel pump. It pressurizes the system to be ready when you go to crank it. A sort of "pre-prime" I suppose.

I just remembered another one. A clicking right after I turn it off. Seems to come from the throttle body (so I suppose it's quite possible it's the throttle actuating).

My fuel pump sometimes runs when i open the drivers door.

I think that is the throttle plate closing. My GP GXP had a fly by wire TB and it did it too.

[classicjetta]

I know the buzzing sound is the fuel pump. It pressurizes the system to be ready when you go to crank it. A sort of "pre-prime" I suppose.

I just remembered another one. A clicking right after I turn it off. Seems to come from the throttle body (so I suppose it's quite possible it's the throttle actuating).

Yep, the DBW throttle makes noise after shutdown; especially noticeable if you're in a garage.

[Earlskey]

Let's not forget the ABS system check sound. This is a knocking sound that comes from the passenger side rear of the car. I notice it from time to time and it seems to happen randomly. It's been doing it since mile 0.
I also noticed an electric buzzing sound when I open my drivers side door. Not sure what that is.

wow, is that what that knocking sound is?! man i've always thought that was something knocking around in my car that i could not find.

[jaso028]

Let's not forget the ABS system check sound. This is a knocking sound that comes from the passenger side rear of the car. I notice it from time to time and it seems to happen randomly. It's been doing it since mile 0.
I also noticed an electric buzzing sound when I open my drivers side door. Not sure what that is.

I though we had gremlins in our glove box!
glad to know thats what it is though, Dealer told us it had something to do with the climate control...

think this 2.5 makes more noise then any VW I have ever heard... lol even my 2.0l ABA made noises but nothing like this...

now the whine you guys speak of, could this have something to do with a hollow cam?

I know in my 24v with the stock cams, they are hollow and produce like a supercharged type of sound.. once you get rid of them for real cams.. the noise is gone!

[LampyB]

i definitely know the whine everyone's referring to, it's strange but always done it on my '08. after installing the BFI tranny insert there's a very prominent whine when accelerating in 2-4th gears in the low rpm range, then it fades out above the 3K mark. this is normal though, after searching it seems as though everyone has the whine with aftermarket tranny mounts, across the MKIII/MKIV/MKV platforms.

[scorch07]

Heck I have the whine and I don't have any aftermarket mounts. I still can't figure it out.

[matt_s]

has anyone tried running an oil additive such as the Lucus Synthetic oil stabilizer to help quieten some of the noises in the head?

[biggs88]

has anyone tried running an oil additive such as the Lucus Synthetic oil stabilizer to help quieten some of the noises in the head?

Lucas oil stabilizer is a sham. All it does is dilute the oil's own additives (which are very good in any VW502 spec'ed oil that is called for in the 2.5L) and thicken the viscosity.

Also, it has been shown to cause foaming in motor oil. And that is not good for your engine.


http://web.archive.org/web/201009261...ucas/lucas.htm

Volkswagen engineers have gone ahead and studied, analyzed, and set oil requirements for our engines. If you think they missed something and you can "fix there flawed specifications" then by all means, use a oil additive.

Stick with a quality spec'ed oil and you and your 2.5L will be fine.

[matt_s]

Lucas oil stabilizer is a sham. All it does is dilute the oil's own additives (which are very good in any VW502 spec'ed oil that is called for in the 2.5L) and thicken the viscosity.

Also, it has been shown to cause foaming in motor oil. And that is not good for your engine.


http://web.archive.org/web/201009261...ucas/lucas.htm

Volkswagen engineers have gone ahead and studied, analyzed, and set oil requirements for our engines. If you think they missed something and you can "fix there flawed specifications" then by all means, use a oil additive.

Stick with a quality spec'ed oil and you and your 2.5L will be fine.

Yea. Im not saying they missed something in there oil. Just wondering if there was a way to make it quieter. I hate how loud that motor is... I've always stuck with vw spec oil for my car to.

[scorch07]

I though we had gremlins in our glove box!
glad to know thats what it is though, Dealer told us it had something to do with the climate control...

think this 2.5 makes more noise then any VW I have ever heard... lol even my 2.0l ABA made noises but nothing like this...

now the whine you guys speak of, could this have something to do with a hollow cam?

I know in my 24v with the stock cams, they are hollow and produce like a supercharged type of sound.. once you get rid of them for real cams.. the noise is gone!

I think I may have heard this whine when I accidentally revved kinda high earlier (forgot it was in tiptronic... oops). More of a whistle? The other whine I hear most of the time is more of a lower waaaaahhhhh

[scorch07]

I think I noticed a new one. Well, I've noticed it before but I narrowed it down more. It's sort of a light but steady thunking noise. Just clunkclunkclunkclunk at a fairly quick rate. But there's two weird things about it.

1) It only happens when the car is in gear. As soon as I put it in drive or anything it stops.

2) I can only hear it inside the car. Can't hear it in the engine bay at all, at least not over the other noises of the engine.

It also seems to do it more when it's cold out and it's a cold start. I'm just guessing it might be transmission related since it's only in neutral. I'm really starting to not like this transmission all that much... gosh I wish it was MT.