Turbo afterrun system question

Jonas Majauskas jmajau at balt.net
Thu Nov 27 02:59:19 EST 2003

On Wed, 26 Nov 2003, Phil Rose wrote:

> It's possible  that the afterrun switches have poor quality control
> (i.e., large variability in the set point temp), or perhaps the
> afterrun relay has a tendancy to be (or to become) "out of spec",
> whatever that may mean.  What's left? Well, I suppose wiring harness
> faults, or even car-to-car differences in engine/turbo cooling
> efficiency. A great mystery, but one not to fret much about unless
> you find that your afterrun _never_ functions. Then there's always
> the old work-around of allowing 30-60 seconds of idling before
> switching off the engine whenever the turbo has been pushed hard.
> Good time to meditate, take deep breaths.

Somebody told me that after hard driving there must be 1-5-10 minutes
(depending on how "hard" it was) idle period, otherwise some of the engine
oil will "cook" in the turbo. No afterrun will help this - it's cooling
capabilities are not so great as oil cooling.

"Hard driving" means 0-100-0-100-0-100-0 as fast as you can :) After that
(do not switch off engine) you will have red brake disks (well, it would
be better to cruise slowly without braking along until they stop glowing
red ;) ), if you open the hood at evening - you should see exhaust
manifold glowing red (nice picture :)). If you switch off engine in such
condition - no afterrun will rescue your turbo (of course, it could take
more than 1 time to ruin completely the turbo, it depends on engine oil).

After 5-10 minutes, when I switch off the engine, the afterrun pump and
radiator fan (at "slow" speed) goes on.

If I use my a200q20v for everyday driving - afterrun does not activate,
because engine temperature is not so high. There are some exceptions, when
wheather is very hot, and the climat control on - engine temperature goes
up after I switch off engine.

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