2002 Audi A4 3.0 6 speed Engine Noise diagnose
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1st Gear
Joined: Aug 2012
Posts: 3
2002 Audi A4 3.0 6 speed Engine Noise diagnose
Hello, after reading several forums trying to diagnose this particular sound I have decided to start a new thread.
I recently purchased a 2002 audi a4 3.0 quattro. Upon a diagnostic test, test drive, and general assessment, I concluded the car was in great shape for having 110xxx miles (mostly highway). After two hours of steady driving I began to hear an abnormal noise that can be described as something between a tick or a knock from the passenger side rear engine compartment.
There are No check engine lights on this vehicle.
I dont believe I am experiencing any irregular oil temps or loss of power.
This sound is mostly present at Idle AFTER the engine has warmed up (sound is not present at cold start) which proceeds to get louder until 2000 rpms. Once I shift past 2cnd gear (or driving above 2000 rpms) the noise is significantly reduced. I am not sure if it is simply dampened by the engine or if it actually goes away. I will have to double check but when I am in neutral the noise is still present after 2000 rpms (I think).
The noise sounds mostly abrasive, and almost sounds like a diesel. At this point I assume it is either the lifters, or a cam adjuster.
I understand that this particular year has issues with
-lifters
-cam lobe wear
-oil sludge (which basically contributes to the above problems)
-catalytic converters
-there was a TSB for audi's of this year and model that was particular about a "ticking/knocking" noise being common when the car warms up which is supposed to go away after the a couple of seconds.
Thus far, I have
-changed the oil (mobile 1 0w30 synthetic)
-replaced the serpentine belt and tensioner
-opened the valve covers to check for cam lobe wear (if there is any, its too minor to tell)
-dropped the oil pan to check for sludge, metal shavings, or mesh screen blockage
-ran seafoam through the vacuum line, crankcase, and gas tank hoping to clear any stuck lifters and clean out any carbon build up throughout the car
I want to extend my thanks to CyberPMG for an excellent write up (Death of a 3.0 (long)) which basically made me rush to get the valve covers open. Thankfully as i said, the cam lobes look intact and I found no metal of any kind in the oil pan when I dropped it.
I currently need to change the oil and filter again to get the seafoam out of the crankcase. Despite what I have done, I can't pinpoint the noise.
Additional Info:
I have access to an Audi tech and tools to maneuver around the engine.
When I took the car in for an oil change a separate tech did say the noise is irregular but I neglected to pay the 100 dollar fee to diagnose (I pretty much knew they were going to want to charge me hundreds of dollars to open the valve covers which I can do myself for free).
Other forums I found helpful were these
HELP!! LOUD ticking noise from the engine under 1200rpm..... - AudiWorld Forums
Very faint ticking clicking sound coming from engine while accelerating????
3.0 engine noise - Audi Forums
This video sounds very close to what I am experiencing but this noise sounds a lot more like a tick than mine does
Any help or ideas would be greatly appreciated. This audi is a weird/ fun beast and I'm having fun learning how to work on it. If you guys have any recommendations for where to find the cheapest/ best replacement parts please feel free to inform me. Look forward to hearing your replies and thanks for the time.
I recently purchased a 2002 audi a4 3.0 quattro. Upon a diagnostic test, test drive, and general assessment, I concluded the car was in great shape for having 110xxx miles (mostly highway). After two hours of steady driving I began to hear an abnormal noise that can be described as something between a tick or a knock from the passenger side rear engine compartment.
There are No check engine lights on this vehicle.
I dont believe I am experiencing any irregular oil temps or loss of power.
This sound is mostly present at Idle AFTER the engine has warmed up (sound is not present at cold start) which proceeds to get louder until 2000 rpms. Once I shift past 2cnd gear (or driving above 2000 rpms) the noise is significantly reduced. I am not sure if it is simply dampened by the engine or if it actually goes away. I will have to double check but when I am in neutral the noise is still present after 2000 rpms (I think).
The noise sounds mostly abrasive, and almost sounds like a diesel. At this point I assume it is either the lifters, or a cam adjuster.
I understand that this particular year has issues with
-lifters
-cam lobe wear
-oil sludge (which basically contributes to the above problems)
-catalytic converters
-there was a TSB for audi's of this year and model that was particular about a "ticking/knocking" noise being common when the car warms up which is supposed to go away after the a couple of seconds.
Thus far, I have
-changed the oil (mobile 1 0w30 synthetic)
-replaced the serpentine belt and tensioner
-opened the valve covers to check for cam lobe wear (if there is any, its too minor to tell)
-dropped the oil pan to check for sludge, metal shavings, or mesh screen blockage
-ran seafoam through the vacuum line, crankcase, and gas tank hoping to clear any stuck lifters and clean out any carbon build up throughout the car
I want to extend my thanks to CyberPMG for an excellent write up (Death of a 3.0 (long)) which basically made me rush to get the valve covers open. Thankfully as i said, the cam lobes look intact and I found no metal of any kind in the oil pan when I dropped it.
I currently need to change the oil and filter again to get the seafoam out of the crankcase. Despite what I have done, I can't pinpoint the noise.
Additional Info:
I have access to an Audi tech and tools to maneuver around the engine.
When I took the car in for an oil change a separate tech did say the noise is irregular but I neglected to pay the 100 dollar fee to diagnose (I pretty much knew they were going to want to charge me hundreds of dollars to open the valve covers which I can do myself for free).
Other forums I found helpful were these
HELP!! LOUD ticking noise from the engine under 1200rpm..... - AudiWorld Forums
Very faint ticking clicking sound coming from engine while accelerating????
3.0 engine noise - Audi Forums
Turns out that there is a valve (intake manifold rotary change-over valve) that runs right through the inlet manifold in the centre of the V and this rotates to change between short and long induction paths at different rpm. The spring betweeen the actuator (2 vacuum cylinders on the front of the engine) and the valve breaks causing the valve to rattle. This then damages the nylon seals in the valve, causing induction leak between cylinders which eventually when it gets bad gives misfires and loss of power.
If this is your issue, its easy to check, pull the plastic cover off the front of the engine, and take the vacuum cylinder module off, (2 torx bolts) and see if the spring is intact.
If you do have a problem with valve lifters, then this also helps diagnose, because you can then slide the valve out a little, not all the way because the radiator is in the way, but if it is covered in wet oil, then the seals on the valve lifters are failing and allowing too much oil back into the inlet manifold.
If this is your issue, its easy to check, pull the plastic cover off the front of the engine, and take the vacuum cylinder module off, (2 torx bolts) and see if the spring is intact.
If you do have a problem with valve lifters, then this also helps diagnose, because you can then slide the valve out a little, not all the way because the radiator is in the way, but if it is covered in wet oil, then the seals on the valve lifters are failing and allowing too much oil back into the inlet manifold.
Any help or ideas would be greatly appreciated. This audi is a weird/ fun beast and I'm having fun learning how to work on it. If you guys have any recommendations for where to find the cheapest/ best replacement parts please feel free to inform me. Look forward to hearing your replies and thanks for the time.
Thread Starter
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1st Gear
Joined: Aug 2012
Posts: 3
Got the car up on a lift to double check origin of noise. After listening for a while, we tracked it down to the timing compartment of the engine rather than the rear passenger compartment.
Opening up timing covers didnt reveal any serious slack in the belt. After getting the engine to warm up and make the noise, I revved it and found that the hydraulic tensioner was failing. This caused a small amount of slack in the belt once the engine was warm. I didn't have the tools or the know how to lock the necessary components in place to remove the tensioner so I had a local audi shop do it for 300 (included the cost of the part). Noise no longer persists and my audi is running great.
Opening up timing covers didnt reveal any serious slack in the belt. After getting the engine to warm up and make the noise, I revved it and found that the hydraulic tensioner was failing. This caused a small amount of slack in the belt once the engine was warm. I didn't have the tools or the know how to lock the necessary components in place to remove the tensioner so I had a local audi shop do it for 300 (included the cost of the part). Noise no longer persists and my audi is running great.
1st Gear
Joined: Sep 2012
Posts: 2
My a4 1.8t 2004 audi just explode today. I park it then within seconds heard a load explosion. Then saw fumes coming from my bonnet. Open the bonnet to see the radiator cap dislodged. Look like it is crystalized. I put new coolant into the vehicle but with minutes its goes empty again. The inside temperature gauge is not showing it to be over heating. Can anyone help with this. I just bought this car 3 weeks ago and am new to owning an audi
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JeremeyAllen
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Mar 25, 2012 05:20 PM
