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Driving temp & overheating

1K views 16 replies 7 participants last post by  johnlear 
#1 ·
So my 156 1.8 TS CF3 is running at around 85°c under normal conditions (main roads) - around 90°c on motorway, and it heats up as quick as I expect it.
However, sitting in traffic, even at days with only 18-20°c ambient temp, it will quickly heat up to +95°c.
The radiator itself is new (replaced by previous owner). Considering that heat-up and running temp is ok, I have a hard time believing that it's the thermostat causing this (unless of course it doesn't open fully).
The fan runs - although, I haven't checked if it actually goes on both speeds.

Where do I start? Say my fan does run on both speeds, then what?
I wouldn't dare a road trip to Italy, risking a traffic jam in 40°c...
 
Discussion starter · #3 ·
To me it sounds like your fan only run at high speed.
If the temperature rises and the fan kicks in, do the temperature continue to rise?

If the fan only run on high speed it is probably the resistor unit or the low speed relay that has broken
Do you have the wiring diagram?
The temp doesn't go down with the fan running.. So I'm more inclined to think it goes opposite of what you're saying - that it maybe only runs on low speed.
I will check fan speeds later today.

Forgot to mention that there's no coolant useage and level is fine as well.

I have access to AutoData, so I can pull out a diagram yes :)
 
Discussion starter · #5 ·
I would also, if possible, compare the temperature as read via OBD with that displayed on the gauge (the OBD temp is the temp as read by the ECU).... The gauges on 156 have been known to be off.
Fans etc are controlled by the ECU, which uses a separate temp sensor. Gauge has it's own sensor.
I'm aware the gauge is off - the temps I provided in the posts are actual temps, not read from the gauge, but through OBD ;)
 
Discussion starter · #8 ·
Switching temps for the fans are :

first speed: 95 degr
second speed: 102 degr

So as said, doesn't seem too abnormal.....
That high, really? My fan is mostly on, when I pull into my drive-way on the way home from work.. As I mentioned it's usually around 85°c under normal conditions, so why is it on that "low"? Because of AC?

Well I've seen it up to 98°c, before I've chosen to put the interior heating on full blast to keep it down..

I was unable to activate the fan relays via AlfaOBD, but I will try switching the relays around, just to verify that both relays are OK.
 
Discussion starter · #13 ·
Seriously, that isn't over heating. Certainly no need at all to panic and put the heating on...

Remember that 100degC is NOT boiling for two reasons.
1) The coolant isn't water. So has a boiling point well over 100.
2) It is under pressure, which raises the boiling point even further.

I once used a coolant with a boiling point of 180degC.


But obviously make sure that the fans work at both low speed and high speed.
But just because it's not boiling doesn't mean it's ideal.. To me at least, 105°c is pretty critical, but maybe I remember wrong.. But that's around where I'd expect the head to start warping :idea:
 
Discussion starter · #15 ·
I haven't.. And unfortunately I'll be busy most weekend, so won't be able to check until sometime next week.
 
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