[Biturbos4] S4 Biturbo newbie

[Grant]

Ah, I "assumed" ...

Turbos run hot - really hot.  I've seen them glow at night after a 
2-hour run on the highway.
So if you run them hard, then immediately turn off the motor, the oil 
stops circulating, and a little bit sits there in the turbo bearing and 
cooks -either into sludge or into coke (which is a little softer than 
diamond and will destroy a bearing pronto).

So, the best advice is: after any hard run, let the engine idle for 
60-90 seconds, while the oil circulates through the turbo, cooling it.  
Then when you shut down, the remaining oil does not cook.

Please overlook the fact that your [potential] Audi has water cooling 
and an after-run pump. yes, they help alleviate this issue. but its 
still good advice.  not necessary if you're just putting around town.

Grant
On Dec 22, 2004, at 9:33 AM, Paul Jones wrote:

> Outstanding info! But I must admit I'm a tad confused about the "cool 
> it down before shutting the engine off" bit. What are you supposed to 
> do?
>
>
>> From: Grant <gfl1 at optonline.net>
>> To: Paul Jones <elsey12 at hotmail.com>
>> CC: biturbos4 at www.audifans.com
>> Subject: Re: [Biturbos4] S4 Biturbo newbie
>> Date: Tue, 21 Dec 2004 19:24:25 -0500
>>
>> Mine's been pretty good.  Very solid car.
>> The turbos are a costly, fragile part however.  For starters, there 
>> are two.  They need to be replaced in pairs, supposedly.  Replacement 
>> requires engine removal, so its costly.  On the other hand, Audi has 
>> equipped it for longevity. The turbos are water-cooled, and there is 
>> an after-run pump to keep H2O circulating after you shut it off.
>>
>> There is no maintenance possible per se, btu precautions that apply 
>> to ANY turbo car:
>>
>> 1. Easy when its cold
>> 2. Cool it down before shutting the engine off
>> 3. Use synthetic oil, which resists coking at the higher temperatures 
>> that exist at the turbo
>> 4. Change it frequently, I do it ~5k with Mobil 1
>>
>> Problem with a used one is "what did the previous owner, who didn;t 
>> plan to keep it long anyway, do?".  frequently, not much.  Audi does 
>> NOT pay for synthetic in 6-cyl turbos, so it got regular oil for the 
>> first 50k, unless the owner carried a bag of mobil 1 to the dealer 
>> twice a year (like I did).  Did he cool it down?  Warm it up?
>> You'll just have to feel out the owner and hope for the best.  Do 
>> listen for excessive whining under load ( a bad sign).
>>
>> Other than that, the timing belt service is a bit costly, and should 
>> be done at (let the debates begin) ~75k.  Figure $900-1500, depending 
>> on who does it, with the water pump, thermostat, idler and tensioner 
>> all at the same time.
>>
>> Tie rods fail early, as do some control arms.  Life goes on.
>>
>> Despite all this, the car has been very solid.  Heavy duty 
>> throughout.  20mpg "normal", with 25+ on the highway.
>>
>> Oh, yea, tune ups are a bear for the DIY, but do-able. Also, careful 
>> of the 17" wheels with 45-series tires.  They bend.  You can get 16' 
>> on for snows, but only a select few 16" will clear the big brakes.
>>
>> Mine now has 73k, no rattles, burns almost no oil, no major repairs 
>> save the tie-rods and a couple control arms.  And once done, it drove 
>> *like new*.
>>
>> Grant
>>
>> On Dec 21, 2004, at 10:21 AM, Paul Jones wrote:
>>
>>> Hi all. I have recently sold my '93 V8 and I am considering buying a 
>>> '00 S4. Having had no previous experience with turbo Audi's I am in 
>>> need of some basic info. on the cars. What are the major problem 
>>> spots? What are the major buyers guidelines? Plus, is there any 
>>> special maintainence that must be performed on the turbos 
>>> themselves?
>>>
>>>
>>> _______________________________________________
>>> Biturbos4 mailing list
>>> Biturbos4 at www.audifans.com
>>> http://www.audifans.com/mailman/listinfo/biturbos4
>>>
>>
>
>