Tapping noise when hot ('96 A6Q 122 kmi).
01-20-2006, 06:18 PM
#1
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Tapping noise when hot ('96 A6Q 122 kmi).
Initially the tapping noise was when the engine was cold and the oil new. Besides, the car had developed sludge under the valve covers. I read posts against engine flush and I decided to do the following:
1. Cleaned the gunk under the both valve covers (mechanically and with solvent, made sure it not get into the engine).
2. Replaced the pressure relief valves (the little hexagons, one on each side).
3. Cleaned under the vally pan; replaced the gasket.
4. Cleaned the IM, TB, EGR passage and replaced the gaskets. Cleaned the ISV; idling little rough now.
5. Replaced the oil retain valves (two) under the valey pan cover.
6. Took off the lower oil pan and cleaned the screen, pan; not too dirty, though. Used the same gasket, put silicone sealant (from dealer) only on the exterior.
After these used Castrol 10W40 (nonsynthetic) for 1000 miles.
7. Now running on Mobil1 5W40 truck/SUV + Mobil1 oil filter. Oil level at MAX, 500 miles on oil.
I cannot figure out why the noise persists after all these changes. The tapping noise cannot be heard at idling, it starts over 1500 rpm. If the car is on ramps (front) it dissapears, but it returns after a while.
Always using 93 octane.
Please advise.
1. Cleaned the gunk under the both valve covers (mechanically and with solvent, made sure it not get into the engine).
2. Replaced the pressure relief valves (the little hexagons, one on each side).
3. Cleaned under the vally pan; replaced the gasket.
4. Cleaned the IM, TB, EGR passage and replaced the gaskets. Cleaned the ISV; idling little rough now.
5. Replaced the oil retain valves (two) under the valey pan cover.
6. Took off the lower oil pan and cleaned the screen, pan; not too dirty, though. Used the same gasket, put silicone sealant (from dealer) only on the exterior.
After these used Castrol 10W40 (nonsynthetic) for 1000 miles.
7. Now running on Mobil1 5W40 truck/SUV + Mobil1 oil filter. Oil level at MAX, 500 miles on oil.
I cannot figure out why the noise persists after all these changes. The tapping noise cannot be heard at idling, it starts over 1500 rpm. If the car is on ramps (front) it dissapears, but it returns after a while.
Always using 93 octane.
Please advise.
01-20-2006, 07:26 PM
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Re: Tapping noise when hot ('96 A6Q 122 kmi).
Sounds like it could be "rod knock" (worn out rod bearings), or "piston slap" (too much clearance between piston and cylinder wall).
Here's some links (copy/paste) that describe each:
Rod Knock
http://www.americascarshow.com/glossary/Welcome.html?index=R
Piston Slap
http://www.canadiandriver.com/articles/jk/020320.htm
Here's some links (copy/paste) that describe each:
Rod Knock
http://www.americascarshow.com/glossary/Welcome.html?index=R
Piston Slap
http://www.canadiandriver.com/articles/jk/020320.htm
01-23-2006, 01:27 PM
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Re: That's wired. oil too low? Was the noise while in D or P?
i think it was low, although i didn't measure how much fluid i drained. the noise occured in D and P. the tick was in the car when i bought it 1 year previous, the noise was diagnoised as tappet [lifters] leaking manifold gasket so i let it go until i made time to fix it. 1 month ago i was towing a trailer on a hot day and the tranny went to limp mode. thats when i drained the fluid, the fluid was a little smelly. i've drained it again and now there's a cavation noise under light load when cold.
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