the engine noise continues

"OPPOsaurus WRX" (opposaurus) 07/21/2016 at 15:25 • Filed to: None

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I posted on Audizine but havn’t gotten much of a response.

http://www.audizine.com/forum/showthre…

I have watched a bunch of youtube videos but non have the same issue as I have.

Could I need a new fan? There are 3 fans in front of the car. Two behind the Radiator and one in front. The larger fan (by the oil dip stick) turns but the one to the left does not even after the car has been warmed up. There is also a fan in front of the radiators that does not turn. I’m pretty sure its the A/C but the A/C doesn’t seem to work and that’s not really a concern right now. The noise seems to be lasting longer now, where before it would stop after I got back up to speed.

original post:

After about 20 mins of driving the sound of my engine changes. It sounds almost like a giant fan and loses the ‘throaty’ sound. If I get back up to speed it usually goes away by 30 mph or so and the engine sounds returns to normal. This doesn;t seem to be a sound overpowering the engine but the engine itself.

There no squealing or ticking or dentist drill sounds (bad turbos). I guess the closest thing could be a window A/C unit. I suspect it has something to do with the temperature of the engine. The engine seems to run at a normal temperature and performance doesn’t really change at all. i just did an oil change and it didn’t make any difference. The temperature doesn’t jump up if I stop either.

I just passed 177k miles. You want to make tow truck jokes please go somewhere else. I’m going to go DRIVE home now. Thanks.

SidewaysOnDirt still misses Bowie > OPPOsaurus WRX 07/08/2016 at 12:11

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Are they there to tell you if the car’s running? How often is that? I imagine not very. [/making fun of the allroad]

OPPOsaurus WRX > SidewaysOnDirt still misses Bowie 07/08/2016 at 12:13

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so funny

Dave the car guy , still here > OPPOsaurus WRX 07/08/2016 at 12:42

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If like most Audi I’ve worked on the primary fan is the one in front of the dipstick, the other is the A/C fan . The left hand side fan is primary, and always determined by sitting in the drivers seat not standing in front of the vehicle. When your A/C cycles on the air conditioning fan should be running to help cool the condenser and make the gas charge go back to high pressure liquid before it gets to an orifice or expansion valve. I had that one failing on my old A4, it would run but got very noisey like you’re describing. If that fan isn’t running all the time your compressor clutch is engaged you have either a fan, fan control, switch or wiring issue. Those fan if running and bad are a lower howl not the jet whine of a bad Pierburg secondary air injection pump. If anyone here has ever worked on a GM vehicle with a SAI pump that didn’t die but whined you’d know the noise because the same company made yours.

OPPOsaurus WRX > Dave the car guy , still here 07/08/2016 at 12:44

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yea my secondary pump is in need of replacing but that only acts up at start up. whats the third fan for then?

Dave the car guy , still here > OPPOsaurus WRX 07/08/2016 at 13:09

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Not sure, you may have a aux radiator or cooler like the VW Phaetons had. I’m not real familiar with the setup on the Allroads. All my cars have been 1.8t, 2.8 or 3.2 engines. Do a Google search for “Audi parts online” there are a lot of dealers that you can access the factory parts pics on so you can identify the pieces.

ESSSIX GmbH - Accountant/Wagon Thumper > OPPOsaurus WRX 07/08/2016 at 13:16

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I have block off plates for the combi valves if you decide t ditch the SAI system.

torque > OPPOsaurus WRX 07/08/2016 at 14:32

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OP (serious question) did you try searching (and if no results) asking your question on an Audi or allroad specific forum like fourtitude or audiworld?

I know personally Fred’s (i.e. TDIClub) has been very helpful for a few headscratchers on my TDI

OPPOsaurus WRX > torque 07/08/2016 at 14:58

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i had done a very small amount of searching. I searchED audi 2.7t engine noises and google crashed with too many results I found a bunch of stuff but nonE matched my noise. I havnt done any forum searches. usally OPPO is my one stop shop for all answers

torque > OPPOsaurus WRX 07/08/2016 at 15:13

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I’d recommend giving Fortitude a shot (or another shot), I’ve heard good things about that one, but I’m not really on it myself b/c my VAG is a VW not an Audi.

Just like any other auto problem, the probability you’re the 1st to encounter (and write on “the internets”) about a particular problem are low. Granted unique NVH can be tricky to RCA (root cause analysis)

Dave the car guy , still here > OPPOsaurus WRX 07/08/2016 at 15:56

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Forgot to tell you that the secondary pumps can sometimes be revived. If the aluminum rivets are corroded and rotting away the case separates some. Drill out the aluminum and replace them with long cheap machine screws and nylon lock nuts from the hardware store for about $8. It will often pull the case together enough to kill the noise. After you get it reinstalled drill a tiny drain hole in the bottom of the pump fan housing to make sure any water that collects in it can get out. I suggest something small like about 1/16" or just under. Otherwise its best on these cars to pull one of the SAI hoses on every oil change which is a pain to do. Some guys also spray Blaster or WD40 into the fan housing to displace the water and fight corrosion. Gave a friend a revived pump that’s now been on his A4 for 5 yrs with no issues.

Ash78, voting early and often > OPPOsaurus WRX 07/21/2016 at 15:32

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My 2.8 had an electric fan and a belt-driven clutch fan. The latter is the one that failed after about 10 years. I didn't have any overheating issues, but my mechanic recommended it anyway as part of my TB service (rather than come back and pay him later). It wasn't making any sounds, it just wasn't working.

Spaceball-Two > OPPOsaurus WRX 07/21/2016 at 15:34

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I think it’s your secondary injector pump. I replaced that on my A4 not too long ago. Eventually it will die and throw a CEL but it won’t bother performance.

Daily Drives a Dragon - One Last Lap > OPPOsaurus WRX 07/21/2016 at 15:36

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And that has the 2.7?

TeamClearCoat > Dave the car guy , still here 07/21/2016 at 15:36

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Came here to suggest SAI. So, seconded.

TeamClearCoat > TeamClearCoat 07/21/2016 at 15:36

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Also, try VWVortex.

OPPOsaurus WRX > Spaceball-Two 07/21/2016 at 15:41

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your both right and possibly wrong. My SIP is wacked but it only happens at cold startup and then goes away after a minute or two. This happens way after that has shut up. Could it also be responsible for this? The SIP makes a jet-engine sound at start-up and this noise is different, less high pitch than the SIP

Spaceball-Two > OPPOsaurus WRX 07/21/2016 at 15:44

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It starts out as a quiet fan noise and as the bearings get worse and worse before it seizes it becomes that loud jet noise. Regardless I hope it's a cheap fix!

OPPOsaurus WRX > Dave the car guy , still here 07/21/2016 at 15:44

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clutch is engaged you have either a fan, fan control, switch or wiring issue

I’m starting to think you have something here. I think the A/C is infront of the radiator, but there are two behind, one must be the Aux fan. So the right side fan (from sitting in the drivers seat) is the one that doesn;t seem to work. IS this an easy replacement?

OPPOsaurus WRX > Daily Drives a Dragon - One Last Lap 07/21/2016 at 15:45

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yes

CalzoneGolem > OPPOsaurus WRX 07/21/2016 at 15:45

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You want to make tow truck jokes please go somewhere else. I’m going to go DRIVE home now. Thanks.

As a former PT Cruiser owner this is only going to get people to make more fun of your Besidetheroad.

OPPOsaurus WRX > Spaceball-Two 07/21/2016 at 15:46

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the SIP doesn;t run constantly tho right?

Spaceball-Two > Dave the car guy , still here 07/21/2016 at 15:46

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I wish I had this tip a couple months ago.

Spaceball-Two > OPPOsaurus WRX 07/21/2016 at 15:47

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No. But it will find odd times to just randomly go off.

OPPOsaurus WRX > Spaceball-Two 07/21/2016 at 15:48

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it does, about 5 minutes after driving it will come on when I come to a complete stop but it shuts off again after 30 seconds or so. The other noise is continuous.

Daily Drives a Dragon - One Last Lap > OPPOsaurus WRX 07/21/2016 at 15:55

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I’ve asked a b5 s4 owner but I think he’s out of town so I might not get an answer.

Spaceball-Two > OPPOsaurus WRX 07/21/2016 at 15:57

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Interesting. I’m surprised the other forums haven’t jumped in with some conclusions.

Dusty Ventures > OPPOsaurus WRX 07/21/2016 at 16:00

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I know what you need...

Dave the car guy , still here > OPPOsaurus WRX 07/21/2016 at 16:11

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Not too bad. I know the A4 and S4 could have the front put in “service position” that pulls the core support with radiator and condenser forward an additional 6-8 inches so you have room to work. It required removing the bumper and some other fiddly crap but I’d say it should only take a couple hours at most. Its tight in there and most Audi VW fans twist into place to lock some of the pegs and then a few screws to lock it in. You could test the plug to the fan to see it it has power but its not running. Otherwise I’m pretty certain there is a fan control module thats likely failed. So much of the stuff is common to A4 and A6 you might be able to grab a used module at a wrecking yard with a short warranty so you can verify and fix it on a budget. Part numbers would be the same and are actually molded on the part.

Dave the car guy , still here > TeamClearCoat 07/21/2016 at 16:13

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I’m a VW-Audi addict now, at number 4 and daughter just bought her own certified A4. Sadly my bread and butter is GM cars.

Tohru > OPPOsaurus WRX 07/21/2016 at 16:31

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Once the motor stops making all noises, THEN you’ve got problems.

Dr. Zoidberg - RIP Oppo > Dusty Ventures 07/21/2016 at 16:49

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Stop rubbing it in, guy!

OPPOsaurus WRX > Dave the car guy , still here 07/21/2016 at 17:11

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Your awesome. I’ve been looking for an excuse to go back to the pick and pull. I’ll test the fan (bro-in-law has that stuff) then take the trip

OPPOsaurus WRX > Spaceball-Two 07/21/2016 at 17:12

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Other forumsare not as awesome as a OPPO

Dusty Ventures > Dr. Zoidberg - RIP Oppo 07/21/2016 at 18:32

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He has a manual turbo wagon. He misses his WRX. Solution? Get a manual turbo wagon with a WRX motor in it

Cash Rewards > OPPOsaurus WRX 07/21/2016 at 22:05

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I had an 05 mini S (the supercharged ones that had so little room in the engine bay they had to stick the battery in the truck), and it had two radiator(?) fans. One was on all the time, one only came on if it got really hot. Well, the first one died, so the secondary fan kicked on after a few minutes every time I drove the car, and it was loud. Could be the one that isn’t turning, should be, and it causing the second one to come on loudly.

AMGtech - now with more recalls! > OPPOsaurus WRX 07/21/2016 at 22:22

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You could try disconnecting the fans and air injection pump one at a time to see if the noise goes away. It may also be possible that you have a bad thermostat or slightly plugged radiator causing temps to start going high enough to activate a fan at a speed you’re not accustomed to hearing, which would mean the noise is “normal” under certain conditions but those conditions may not be normal meaning you have something else to fix and the nose is just a roundabout symptom.