It may be just that my oil needs changed...
On cold start I get the usual ‘tappety rattle’ from the top end for a couple of seconds as the fluids get back up to the top of the engine. Recently though I get a very slight ticking noise for about a minute, which then passes but on any restart (warm) that tick is there very briefly.
Is there a valve inside which should keep the oil up top, stuck open, could a failed seal someplace create this problem? I’ll change to a different weight of oil but don’t want to hide an underlying issue if there is one.
Advice appreciated.
Rattle on Start
Re: Rattle on Start
Do you leave it a long time between using it??
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c5 rs6 owner thats been known to cut the wrong wire.............
Re: Rattle on Start
Probably a hydraulic tappet that's a bit tired. See what happens after your oil change. Presumably you're using the correct 5W40 505.01 stuff?
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
Re: Rattle on Start
Mine can sound quite tappety if I've left it for a few weeks. This can last for a couple of minutes. It takes a while for the tappets to fully pressurise when they are completely drained.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
Re: Rattle on Start
Same here mate that why I asked how long he left it for-I’m thinking of wiring a switch in from fuse 29 so don’t have to pull the fuse every time I use it as I can go weeks at a time before it gets used-but me a wires don’t get on!
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c5 rs6 owner thats been known to cut the wrong wire.............
Re: Rattle on Start
That's not a bad idea. I should probably do the same.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
Re: Rattle on Start
I don’t know about you but mine rattles like f##k even if it’s left for a week! So I’ve just gotten into the habit of pulling the fuse every time I use it-I did think about a oil pressure gauge too so I could turn it over till it was up to pressure but I don’t want one on show.Shoppinit wrote:That's not a bad idea. I should probably do the same.
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c5 rs6 owner thats been known to cut the wrong wire.............
Re: Rattle on Start
Why pull a fuse ? I'm missing something I think ?
Re: Rattle on Start
Pull fuse 29 to be able to turn over the motor without it actually firing, to build oil pressure.
2004 Audi RS6 Avant Plus #283
Re: Rattle on Start
Ah ! Now I see ! Sure I have seen that in another thread somewhere. Thanks for clearing it up 
Re: Rattle on Start
I think most cases of cold start rattle could be eliminated by means of the starter motor turning for a couple of seconds longer before ignition.
My car starts well within two seconds of the starter turning, hot or cold, which for a fairly large engine is too soon for the oil pressure to have built up.
Could there be a way of mapping in a longer cold start process to allow oil pressure to build up before the engine fires. This would obviously reduce engine wear.
Just my laytards thoughts.
My car starts well within two seconds of the starter turning, hot or cold, which for a fairly large engine is too soon for the oil pressure to have built up.
Could there be a way of mapping in a longer cold start process to allow oil pressure to build up before the engine fires. This would obviously reduce engine wear.
Just my laytards thoughts.
Re: Rattle on Start
Thinking about it ( my car is garaged for more then a year now...) how long to start after pulling fuse 29 to built up pressure ?
If you can't go to the track, bring the track to you.
Mugello Blue C5 RS6 Avant
Viper Tuning ECU/TCU
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MTM exhaust system cat back 4-pipe with throttle valves in 2 pipes, control
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Mugello Blue C5 RS6 Avant
Viper Tuning ECU/TCU
MTM Bimoto wheels 9,5 x 19 ET 30 LK 5x112 with 275/30/19 tyres
MTM exhaust system cat back 4-pipe with throttle valves in 2 pipes, control
Yellow Koni's
Porsche 959, gone but not forgotten.
Fight ALS disease https://www.youtube.com/watch?v=wGFDWTC8B8g
Re: Rattle on Start
You can hear it when the engine becomes pressurised / lubed. Takes about 6 or 7 seconds in my case. Noise level goes down, starter turns slightly more freely. It's a subtle difference, but detectable.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
Re: Rattle on Start
What I have done in the past (albeit a 4 cylinder TDI) is do 3x 5 second cranks with a very short break between to ensure oil pressure had built - this was after many months of just sitting in the garage.
I personally wouldn't want to crank much longer than 10 seconds in a single instance to avoid overheating the starter.
I personally wouldn't want to crank much longer than 10 seconds in a single instance to avoid overheating the starter.
2004 Audi RS6 Avant Plus #283
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