operating temperature?

Bernie Benz b.benz at charter.net
Tue Dec 5 01:07:08 EST 2006

> From: Brett Dikeman <quattro at frank.mercea.net>
> The turbo 20v is a little "infamous" for running cooler than other
> I-5's, at least according to the gauge, in some circumstances.  Some
> have said it is because of the placement on the external coolant
> manifold, others say it is because of the auxiliary radiator.
I don¹t concur with your 20V accusation, in that the cooling ³control²
system is identical to all other I5 systems, and other cars. The thermostat
is the sole controlling thermal component until it is wide open, after which
aux radiators, fans and ram air take over. Thermostats fail, either open or
closed, BTDT, but when you have a good one, DFI if IAB! And don¹t install a
cooler thermostat.

> Wintertime readings just over the three marks to the left-most are
> not uncommon, especially at highway speeds; I'd expect it to be up
> higher around town and in stop+go traffic.
> Almost straight up is about the normal "ceiling" temperature in
> summertime or after idling for quite some time (which Audi says not
> to do.  Owners manual says: get in, turn the key, drive gently until
> temp gauges come up.  Idling to warm up causes excessive wear,
> because tolerances are too tight when not at temperature.   I can
> have heat out my vents in under 2 minutes if I drive out and up a
> section of road that is a very gradual incline, or not have heat for
> quite a bit longer if I just let the car idle.  Power = heat!)
> A better indicator of engine temperature is sometimes the oil gauge.
> It should stabilize at or above 60, ideally sitting pretty on 100.
> Experience may vary with outside air temperature and speed, but
> cruising on level highway doing 70 in 5th, I'd expect to see it
> sitting dead on 100 in mild weather.
> Brett

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