On Fri, 17 Sep 2004 20:10:25 +0200, Arjan Renting >
wrote:

>On 16-9-2004 18:53, Zathras wrote:
<Snip>
>> If by 'parking heater' you mean the ones where you plug them into the
>> mains to heat the car then I wasn't meaning those.
>
>Or on petrol.

Indeed..and diesel powered heaters in some cases too (usually
trucks/vans etc).

<Snip>
>> ? I'm talking about 'cooler weather' when you're *heating* the cabin
>> and thus drawing heat from the heater matrix which is fed from engine
>> coolant IIRC. You're referring to chilling the cabin - I've not found
>> that to have any effect on engine temperature. My loose reference to
>> '156 A/C' really means the whole climate control system (heating and
>> cooling).
<Snip>

> I don't have any explanation for the effect
>you mentioned.

Easy to test yourself. Drive the car until the temp is 90. Stop and
leave the car idling. Turn the A/C (climate controls..whatever you
like to call them) temp to max. Turn the fan to max. Watch how quick
the engine water temperature falls. 5 minutes should be enough for a
significant change. This technique could often get you home in the old
days if you broke a fan belt. It's VERY effective at cooling the
engine.

>My 147 JTD always stays at a 90 deg C no matter what the outside
>temperature is or what the performance is that she has to deliver. On my
>previous cars it was always variable between the 70 and 105 deg C. I
>don't know if it is just a adaptation in the meter, another type of
>thermostat or a different point where the engine temperature is
>measured, or that the engine really stays at 90 deg C all the way.

If you suddenly drive very hard, the engine must produce more heat and
heat up the water before the thermostat can react. It does appear
quite well controlled on the 156 but I can still see the temperature
rise a little within a mile of booting it. Falls back quite quickly
when I slow down and often to below where I started due to the delayed
reactions of the thermostat.

Your car could have a very heavily damped meter (Alfa meters seem to
have character of their own). I don't have enough experience of the
147 to comment accurately on your specific case.

<Snip>
>> I've only experienced thermostat malfunctions that were noticeable at
>> any time of the year.
>
>I had it twice that the thermostat was not closing anymore all the way,
>no trouble in the summer but in autumn it was noticeable. When you start
>to notice that the heater is not able to give some extra push you mostly
>have an problem with the thermostat.

My (non Alfa!) experience has only been where the car doesn't heat up
very much at all (temp gauge at 1/4 expected) or car has overheated.
Not a partial fail like you seem to have had which, I agree, would be
as you say.

--
Z
Scotland
Alfa Romeo 156 2.4JTD Veloce Leather
'Oil' be seeing you..
(Email without 'Alfa' in subject are auto-deleted..sorry!)