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156 1.8TS Overheating

 
Gareth Hill
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      12-05-2006
I've recently started having problems with my 156 1.8TS overheating.
I generally use a local mechanic who I trust and can afford rather than
the local Alfa dealership, but we are struggling to find the cause for
the problem. I'm not a mechanic but am hoping we can find a solution
without resorting to using the dealership!

The water level in the expansion tank is fine, as is the oil level when
checking the dipstick. When the car reaches the 'normal' running
temperature between 70-90, the gauge drops down again before rising,
leading me to think the thermostat is opening. I can moderate the heat
by turning the heater on and the pipe leading into the expansion tank
gets warm, which makes me think the water pump is working.

When the car reaches extreme temperatures (it reached approx. 110 when
I first realised the problem) the radiator fan is not kicking in. Also
the OBD (engine management) light was on for a short period after we
recently changed the cambelt, but the light went off after a week (is
this related?).

These clues point towards it being something sensor or OBD related...?
Anyone any ideas what we should try next?

I've also had suggestions that it could be an air-lock, does this sound
feasible and how would I go about releasing one??

 
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John, UK.
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      12-05-2006
Gareth Hill wrote:
> I've recently started having problems with my 156 1.8TS overheating.
> I generally use a local mechanic who I trust and can afford rather than
> the local Alfa dealership, but we are struggling to find the cause for
> the problem. I'm not a mechanic but am hoping we can find a solution
> without resorting to using the dealership!
>
> The water level in the expansion tank is fine, as is the oil level when
> checking the dipstick. When the car reaches the 'normal' running
> temperature between 70-90, the gauge drops down again before rising,
> leading me to think the thermostat is opening. I can moderate the heat
> by turning the heater on and the pipe leading into the expansion tank
> gets warm, which makes me think the water pump is working.
>
> When the car reaches extreme temperatures (it reached approx. 110 when
> I first realised the problem) the radiator fan is not kicking in. Also
> the OBD (engine management) light was on for a short period after we
> recently changed the cambelt, but the light went off after a week (is
> this related?).
>
> These clues point towards it being something sensor or OBD related...?
> Anyone any ideas what we should try next?
>
> I've also had suggestions that it could be an air-lock, does this sound
> feasible and how would I go about releasing one??


Possibe. Has the water been drained lately? after draining radiator,
the inside car temp [usually on most makes of cars] should be set to
hot before refilling.
I presume you have checked the front of the radiator for rubbish,
paper, plastic bags ect.?
Hope this is of some help.
John,UK.

 
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alfistagj
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      12-05-2006

"Gareth Hill" <(E-Mail Removed)> schreef in bericht
news:(E-Mail Removed) ups.com...
>
> When the car reaches extreme temperatures (it reached approx. 110 when
> I first realised the problem) the radiator fan is not kicking in.


Sounds like the thermostatic switch that engages the electric fan is
defective, or the fan itself.
Simple way to check the fan is to disconnect the wires at the switch in the
radiator and connect them (be sure to switch the ignition "on")
If the fan starts, it's o.k.
Then I'm quite sure it's the switch which you can check if you have a
resistant measuring device; when the coolant reaches 90dgr or so, the switch
should operate.
Easy replacement job.

--
Ciao from The Netherlands
alfistagj (aka Gert-Jan)
GT 2.0 JTS (2005)
Montreal 2.6V8 (1428700 - 1973/4)


 
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Gareth Hill
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      12-05-2006
Thanks for the replies - I will check the fan switch.
I know it is a problem that the fan is not coming on when it is getting
too hot, but I would have thought there must be some other problem
because the fan did not used to come on before unless stuck in traffic
and a really hot day. You knew when the fan was running because it was
really loud. Something else as well as having no fan must be causing it
to get hot as the fan rarely used to come on even when it was working?

alfistagj wrote:
> "Gareth Hill" <(E-Mail Removed)> schreef in bericht
> news:(E-Mail Removed) ups.com...
> >
> > When the car reaches extreme temperatures (it reached approx. 110 when
> > I first realised the problem) the radiator fan is not kicking in.

>
> Sounds like the thermostatic switch that engages the electric fan is
> defective, or the fan itself.
> Simple way to check the fan is to disconnect the wires at the switch in the
> radiator and connect them (be sure to switch the ignition "on")
> If the fan starts, it's o.k.
> Then I'm quite sure it's the switch which you can check if you have a
> resistant measuring device; when the coolant reaches 90dgr or so, the switch
> should operate.
> Easy replacement job.
>
> --
> Ciao from The Netherlands
> alfistagj (aka Gert-Jan)
> GT 2.0 JTS (2005)
> Montreal 2.6V8 (1428700 - 1973/4)


 
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Graham2
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      12-05-2006
"Gareth Hill" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) ups.com...
> Thanks for the replies - I will check the fan switch.
> I know it is a problem that the fan is not coming on when it is getting
> too hot, but I would have thought there must be some other problem
> because the fan did not used to come on before unless stuck in traffic
> and a really hot day. You knew when the fan was running because it was
> really loud. Something else as well as having no fan must be causing it
> to get hot as the fan rarely used to come on even when it was working?
>
> alfistagj wrote:
>> "Gareth Hill" <(E-Mail Removed)> schreef in bericht
>> news:(E-Mail Removed) ups.com...
>> >
>> > When the car reaches extreme temperatures (it reached approx. 110 when
>> > I first realised the problem) the radiator fan is not kicking in.

>>
>> Sounds like the thermostatic switch that engages the electric fan is
>> defective, or the fan itself.
>> Simple way to check the fan is to disconnect the wires at the switch in
>> the
>> radiator and connect them (be sure to switch the ignition "on")
>> If the fan starts, it's o.k.
>> Then I'm quite sure it's the switch which you can check if you have a
>> resistant measuring device; when the coolant reaches 90dgr or so, the
>> switch
>> should operate.
>> Easy replacement job.
>>
>> --
>> Ciao from The Netherlands
>> alfistagj (aka Gert-Jan)
>> GT 2.0 JTS (2005)
>> Montreal 2.6V8 (1428700 - 1973/4)

>


It could be that the hot water is not circulating as far as the radiator, so
the switch will not 'switch' and turn the fan on. Either an airlock, or
thermostat could possibly cause this. Try squeezing the pipes from the
engine to the rad and see if you can feel hotter water flowing in the pipe.

Graham


 
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Gareth Hill
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      01-08-2007
I've finally got round to working on this problem some more because of
the dark nights and have just been controlling the temp manually with
the cabin heaters!

I've checked the OBD for errors which was ok, checked the pipes from
the engine to the radiator and can feel the hot water flowing through
and replaced the resistor on the fan which did not fix the problem.

I am looking to test the fan switch manually now as alfistagj suggested
but non entirely sure how to do this - could anyone give me some
instructions on how to do this, bearing in mind I'm a novice when it
comes to electrics?

 
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di9it8
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      01-13-2007

Is the fan relay working?
If you run the car stationary, until the fan should start, if it does
the relay is ok
I would then look to see if it is a faulty thermostat or problems with
the water circulating

 
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Gareth Hill
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      01-14-2007
Thanks for your reply. I've just changed the fan relay and the fan
still isn't starting when it gets to just below 100 degrees! I'm
assuming the water is circulating as the pipes to and from the radiator
are getting hot and I can cool the engine using the cabin heater fan or
it cools down itself when travelling at speed. The problem all seems to
relate to the fan not being triggered by some sensor. Does anyone know
what sensor it is that should switch the fan on and where it is located
(maybe also what it kind of looks like)? Is the fan controlled by the
OBD software or is there a hard wired sensor? I've been told that 'hard
wiring' the fan to the power would be a good method to test that it is
not just the fan that is broken, but not sure how to go about this?

 
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SteveH
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      01-14-2007
Gareth Hill <(E-Mail Removed)> wrote:

> Thanks for your reply. I've just changed the fan relay and the fan
> still isn't starting when it gets to just below 100 degrees!


Hmmmm - I've had cars that haven't kicked the fan in until they're a
good few degrees over 100. I think my Cinq. kicked in at around 105 -
110 degrees.

--
SteveH 'You're not a real petrolhead unless you've owned an Alfa Romeo'
www.italiancar.co.uk - Honda VFR800 - Hongdou GY200 - Alfa 75 TSpark
Alfa 156 TSpark - B6 Passat 2.0TDI SE - COSOC KOTL
BOTAFOT #87 - BOTAFOF #18 - MRO # - UKRMSBC #7 - Apostle #2 - YTC #
 
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Peter
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      01-15-2007

"Gareth Hill" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) ups.com...
> Thanks for your reply. I've just changed the fan relay and the fan
> still isn't starting when it gets to just below 100 degrees! I'm
> assuming the water is circulating as the pipes to and from the radiator
> are getting hot and I can cool the engine using the cabin heater fan or
> it cools down itself when travelling at speed. The problem all seems to
> relate to the fan not being triggered by some sensor. Does anyone know
> what sensor it is that should switch the fan on and where it is located
> (maybe also what it kind of looks like)? Is the fan controlled by the
> OBD software or is there a hard wired sensor? I've been told that 'hard
> wiring' the fan to the power would be a good method to test that it is
> not just the fan that is broken, but not sure how to go about this?
>


OK, never having had a 156 I can't say for sure
BUT...........................................

You are looking for something called a "Radiator fan switch". Try Google
images for examples.

If you have a friendly MotoFactors near to you simply pop in and they will
check their catalogues and show you a picture of your exact model.

On Rovers I have known the sensor is at the top/bottom of the radiator
itself. It was held in by a locking ring that you could simply push in and
turn and remove.
On other cars I have come across it may be screwed in.
Look for anything attached to the radiator that has wires attached and you
could be onto a winner.

To test the fan itself you will need to apply 12V directly from the battery
to the fan.

Good luck
Peter


 
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