Coolant temp - Alfa Romeo Forum
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Coolant temp

The coolant temp on my 156 V6 sits at just above 70, unless I am in traffic where it rises to 90. As soon as I start moving it drops back to 70 ish again.

I have been told it should rise to 90 and stay there, so I changed the stat for a brand new one and the temperature is exactly the same.

What could be causing this?
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Re: Coolant temp

Misreading gauge? faulty replacement?
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Re: Coolant temp


Hello again to all,

When i purchased my 2002 1.8 Turismo in August the temp gauge seemed low, so i replaced the complete thermostat unit just like you have.

The temp gauge still stays at just over the first (70 o) gauge mark.

If i require a higher reading for the heater etc i just take the revs up to around 6k+ as i go through 2nd, 3rd, and 4th gears and the gauge then goes up enough without getting too hot etc.

Reading through the forums (search) a lowish reading seems normal on the 4 cylinder TS engine.

. Supertrev.


Last edited by Supertrev; 17-12-07 at 15:11.
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Re: Coolant temp

Seems to be a lot of confusion about this. My JTS sits at 70 unless i'm in traffic when it will raise to 90 and the fan cuts in.

Now i've just had a coolant rail replaced and the system tested by Bishops so surely this is how it should be?!?

Last edited by the slipperman; 17-12-07 at 21:45. Reason: cock up on the figure front!
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Re: Coolant temp

Some cars' temp gauges sit perfectly at 90°C all the time, other sit at 70°C when moving and rise to 90°C when stationary and others go up and down between 70°C and 90°C as the thermostat opens and closes. I fitted a new thermostat because my temperature gauge was showing 70°C on the move and 90°C when stationary, and it made absolutely no difference whatsoever. I tested the old thermostat and it started to open at 85°C and was fully open at 95°C. I can only assume that the temperature gauge is inaccurate, and as long as your temperature reading is fairly stable then your thermostat is working.
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Re: Coolant temp

The temperature is meant to stay at 90* as this is the temp were the engine is most efficient. It may be a meter fault or temp sender, but they should be bang on 90* all the time (which is why the thermo only opens around this temperature).
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Re: Coolant temp

I questioned this too, just the thermostat opening and closing, depending on engine temperature. (see New Girl on the Scrounge) Nothing to worry about, unless it goes above 90, then start to worry...!
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Re: Coolant temp

Mine sits a 90 unless in traffic, the fan seems to cut in a tad below 100. But a friend of mines sits a 70 and will only go to 90 if it has been idling for 20 mins or so... his fan kicks in alot lower too!

I guess some variation between cars is normal, and there is always going to be a degree of error with every component involved (gauge, thermostat, valve, fan etc) but will it cause any harm having it sit higher or lower than what is perceived to be normal?

BTW, not been on here for a while, but a friend has just bought a 'do-er up-er" 156 and have been working on his, and to a lesser extent mine today and its kinda rekindled my love for the car and the AO site. Its not that I got that I got bored with either... its just I probably forgot what Alfa ownership is all about!

Im glad to have rekindled my love for it all!

Dispite the cost of living now-a-days, have you noticed how it still remains so popular?
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Re: Coolant temp

can everyone check their tailpipes for soot?
i have a theory - which could be completely wrong! so someone correct me please;
if you have a sooty pipe, your car thinks it is running cold at 70 thus overfuelling?
but if your tailpipe is clean, your car is fine - which means the display is wrong but the actual thermostat is working right?

*of course my soot is most likely to be due to a kaput Lambda
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Re: Coolant temp

It's normal - so long as it doesn't venture ABOVE 90 at any point, you've nothing to worry about.
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Re: Coolant temp

My wife's thermostat is stuck open, she's just using it around town at the moment, and it's not really heating up; she's complaining about not having a heater.
I checked the average mpg yesterday and it was 13mpg!! I knew running cold affected fuel consumption, but didn't realise it was that much!! Time to get my gloves on and replace the 'stat I think....
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