What would cause valve tapping sound at low throttle?
06-15-2006, 04:32 PM
#1
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What would cause valve tapping sound at low throttle?
I have a tapping sound under the valve cover on the left side. It only makes a noise when under light throttle through most of the rpm range. Basically when keeping speed. Push it hard and it goes away.
06-16-2006, 04:21 AM
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Does the clatter get worse when the engine gets hot?
Something may prevent the valve lifters from pressurizing properly. The lifters could be dirty (How clean is your engine internally?) or oil pressure may be a bit low. Consider changing oil viscosity. For example, if you are using a 5W-30, try a 5W-40 and see if that helps.
Of course, you should make sure oil pressure is within specs. You may also want to make sure the oil check valves in the heads function properely. Another possibility is a defective oil filter bypass or anti-drainback valve.
Of course, you should make sure oil pressure is within specs. You may also want to make sure the oil check valves in the heads function properely. Another possibility is a defective oil filter bypass or anti-drainback valve.
06-16-2006, 07:35 AM
#5
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The car is new to me so I don't know the condition inside. Im using Mobile 1 0w40
Its pretty consistant through rpm and temp. Only difference is the throttle %.
06-16-2006, 08:12 AM
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The specs from Audi.............
<center><img src="http://pictureposter.audiworld.com/87187/oil_specs.jpg"></center><p>They make no reference to 0w40 anywhere.
You can use 20w50 in the summer.
You can use 20w50 in the summer.
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06-16-2006, 10:56 AM
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M1 0W-40 made my 12v noisy , too.
There was lots of valve train clatter at hot idle coming from my 12v when I used M1 0W-40. I did not hear any unusual noise above idle RPM, though. Different oils have different noise dampening qualities. The noise is likely harmless, but can be rather annoying.
Audi did not spec a 0W-40 for the 12v, because there were no 0W-40 oils back when that engine was developed. Your engine is supposed to use VW 500.00 or VW 502.00 oil. While M1 0W-40 meets VW 502.00, it is not even recommended by Mobil for the 12v. Go to the Mobil site and use their oil finder to see for yourself, if you don't believe me.
You say you don't know the conditions inside the engine. Well, you certainly know if the engine is cold or at operating temperature when the noise occurs. Your car comes equipped with an oil temperature gauge. ;-) Knowing when the noise occurs, would really help in trying to find the cause.
Audi did not spec a 0W-40 for the 12v, because there were no 0W-40 oils back when that engine was developed. Your engine is supposed to use VW 500.00 or VW 502.00 oil. While M1 0W-40 meets VW 502.00, it is not even recommended by Mobil for the 12v. Go to the Mobil site and use their oil finder to see for yourself, if you don't believe me.
You say you don't know the conditions inside the engine. Well, you certainly know if the engine is cold or at operating temperature when the noise occurs. Your car comes equipped with an oil temperature gauge. ;-) Knowing when the noise occurs, would really help in trying to find the cause.
06-16-2006, 08:26 PM
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If you are not close to a scheduled oil change...
and if you don't want to waste the current oil by doing an early oil change, simply add some M1 15W-50 next time you top the oil off. Even half a quart can make a difference. That should thicken up the M1 0W-40 and might reduce the noise. You can mix M1 0W-40 and M1 15W-50 without any problems. It's worth a shot.