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Cautionary note about variable redline

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Old 08-03-2014, 07:16 PM
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Default Cautionary note about variable redline

Note that it appears the redline moves up when the *COOLANT* temperature reaches normal, not the *OIL* temperature! Starting out on a warm day, coolant hits normal within a half-mile, but oil is still sitting at 150 degF (my normal seems to be 210-214 degF) and the redline is already moved up to the normal position.

Personally I like the *OIL* to be warm to consider the engine warmed up, but apparently the factory doesn't agree. Consider yourself informed
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Old 08-03-2014, 08:23 PM
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It's good advice for the non-mechanically-empathetic. I've always waited for the oil to get good 'n hot before hammering on things.
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Old 08-03-2014, 09:54 PM
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Originally Posted by DeerHunter View Post
It's good advice for the non-mechanically-empathetic. I've always waited for the oil to get good 'n hot before hammering on things.
What does the user manual say for the S6? The RS5 manual says oil operating temperature is reached at 140 degF, even though it will continue to climb until around 200 to 210 or even higher depending on how I drive, but according to the user manual once the oil reaches 140 degF the engine is ready to go.
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Old 08-04-2014, 06:14 AM
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I've always wondered what deciding factor(s) were behind the redline change. I thought I just read that it was based on oil temperature, but I guess not! Strange, because I've come back to my car after it's been sitting a short while to find the coolant temp still at 4 bars, while the redline is down to 5400 and vice versa where I've had the coolant temperature at 2 bars and the redline was still at 6400.

Starting to think it's voodoo.
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Old 08-04-2014, 06:33 AM
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I park in a parking garage in downtown Seattle so my redline stays until both coolant and oil are up to temp.
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Old 08-04-2014, 07:25 AM
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Originally Posted by superswiss View Post
What does the user manual say for the S6?
Good point, I don't recall TFM mentioning it - probably because the A6/S6 don't ship with the oil temperature enabled I'll take a look tonight to see - and thanks for the info from the RS!
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Old 08-04-2014, 09:29 AM
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On the S6 my oil temp starts to register around 140-ish. I usually look for >160 before I use any heavy throttle.

On my stg3 B5S4 my threshold was >175F and the K04s never had any issues.
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Old 08-04-2014, 09:40 AM
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Originally Posted by Richard Solomon View Post
Personally I like the *OIL* to be warm to consider the engine warmed up, but apparently the factory doesn't agree. Consider yourself informed
Good advice. I take it easy for the first 15-25 minutes (light throttle) so all the engine components equalize. Never had a head gasket blow even with engines where it was a known weakness (iron block with aluminum heads).
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Old 08-04-2014, 11:25 AM
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Originally Posted by ronbars View Post
I've always wondered what deciding factor(s) were behind the redline change. I thought I just read that it was based on oil temperature, but I guess not! Strange, because I've come back to my car after it's been sitting a short while to find the coolant temp still at 4 bars, while the redline is down to 5400 and vice versa where I've had the coolant temperature at 2 bars and the redline was still at 6400.

Starting to think it's voodoo.
It is based on oil temperature. The oil needs to reach a certain viscosity before it is safe to rev the engine to redline. It seems that 140 degF is that point if the RS5 is any indication. Synthetic oil has a wide operating range. While 140 is enough for proper lubrication, "normal" operating temperature is around 210 where the oil is hot enough to burn contaminates such as water etc. The sooner you get on the throttle (once it is safe to redline) the quicker the oil reaches the point where it is effective at burning off all that crap. You also want to get the oil real hot on even the shortest trip to help burn off the carbon that would otherwise build up on these FSI engines. So, by taking it easy too long the oil is spending more time at lower temperature and may not even reach the optimal temperature on short trips, which over time leads to carbon buildup.
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Old 08-04-2014, 02:55 PM
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^^^ My philosophy is a little different: The metal bits, which expand at different rates, are still stabilizing, even when the coolant is long up to temp. I figure if the oil is still getting warmer, the block (which can hardly have a worse heat capacity) is too. Hence, no fun until the oil is warm (85-95C, depending upon ambient temps).
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