I dont understand that one Silverbarchetta, if the thermostat is stuck open, then the coolant is being cooled all the time through the radiator. When you are driving, the coolant will be too cool as the water is being cooled whether or not it needs cooling. When you stop in traffic, a functioning thermostat would open fully, the temp would keep increasing then the fan would come in. If it is stuck open, the same would happen it would just take longer for the fans to kick in as the coolant was colder to start with.

I think the setting of the fan and the deadband is such that in a perfect system, the fan switches on only once the thermostat is theoretically open and it turns off before the thermostat theoretically starts to close.

I'm not quite sure how Fiat have designed their cooling system but I think it is meant for warmer climates. I only say this because mine also runs under 90 degrees. I know my thermostat is working correctly because it heats up to 90 and then the stat opens and it falls to under 90 degrees and stays there. I think the cooling system is doing its job too well!

What part of the phrase 'Normal temp for a B is somewhere between 1-4 & 1/2 on the dial' do you guys have difficulty with??

If the car was overcooling then the fans wouldn't come on when the needle reaches 9am..

It is different to most other cars..but its Italian and weird.

If you wish to shell out good money then I'm sure Fiat will be delighted to take it off you. You could always do the cheaper option..like on the old Mini in winter of blocking off half the radiator.

I am in agreement with you rustbucket, my thermostat operates exactly how it should. Although the cooling system may be running cooler, this is not an indication of how hot the oil is. Oil temperature is far more important.

On another note, I used to have an Alfa 156 and if it ran below 90 degrees then something was wrong. Maybe too many have previously owned Alfa's!?

When i bought the car i had also a stuck thermostat. the coolant was running all the time in the engine and the temperature was low constantly.

Then i changed it and the temp is in the middle and a liiittle bit lower in normal driving coditions.On the traffic it raises over the halfway but just a bit. The fans do not operate in that temp.

The only reason for the temp to get higher and operate the fans is on summer traffic jam on an incline or when the car stops after a high speed journey.

Rustbucket said:

What part of the phrase 'Normal temp for a B is somewhere between 1-4 & 1/2 on the dial' do you guys have difficulty with??

If the car was overcooling then the fans wouldn't come on when the needle reaches 9am..

It is different to most other cars..but its Italian and weird.

If you wish to shell out good money then I'm sure Fiat will be delighted to take it off you. You could always do the cheaper option..like on the old Mini in winter of blocking off half the radiator.

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We seem to be getting a little heated over this one, pardon the pun. We're each talking about different things too, by the looks.

On my gauge there is the bottom thick mark at 50'c, the next mark at 70'c, then mid scale 90'c (due East, 3pm, whatever you wish to call it). When I got mine it ran at about 60'c, just like my old 156 did. A new thermostat in and it's now running just under 90'c on the move, same as the Alfa after that stat was changed.

In agreement with Rustbucket, if it's running less than around 80'c on the move it's not too good for longevity of the engine as it won't allow the oil to warm up sufficiently to drive off moisture and contaminants. Also your heater won't be as good as it could be, which is quite relevant in the UK just now!

HP. said:

We seem to be getting a little heated over this one, pardon the pun. We're each talking about different things too, by the looks.

On my gauge there is the bottom thick mark at 50'c, the next mark at 70'c, then mid scale 90'c (due East, 3pm, whatever you wish to call it). When I got mine it ran at about 60'c, just like my old 156 did. A new thermostat in and it's now running just under 90'c on the move, same as the Alfa after that stat was changed.

In agreement with Rustbucket, if it's running less than around 80'c on the move it's not too good for longevity of the engine as it won't allow the oil to warm up sufficiently to drive off moisture and contaminants. Also your heater won't be as good as it could be, which is quite relevant in the UK just now!

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Amen.... I think... Bro

Mine is running a smidge over the chunky 50 degree mark i.e. under the quarter mark; but regulates at 90 perfectly.

New thermostat time methinks. I accept that the "normal" running temp is lower than other 'normal' cars, and that self-regulation temp will almost certainly be higher than running temp.

all in all this whole discussion about thermostats is a moot one... as the temp gauge/sensor is not very reliable. If you want to know for sure if the thermostat/coolign is working as it should you should introduce (third-party) sensors in the cooling and oil circuit.

Or take the sensors/thermostat out of the B and test them in reference circumstances ie pot of water on the kitchen stove

Re: Running temperature (pressure release valve).

You probably don't need a new thermostat but you might well need a new pressure release cap on top of the coolant bottle. Known Fiat fault on various other models inc Coupe, Stilo and Alfa's. Its a common part through most of the range.

Check the black top..you might find crusted coolant around the top of the bottle. if so the spring in the cap has got weak and the top is venting pressure. Low pressure means the coolant won't work so well, won't get so hot, less hot air from the heater etc. Few squids from Fiat and a lot less cheaper than a thermostat.

Re: Running temperature (pressure release valve).

If the coolant pressure is too low, it stands the chance of localised boiling, chucking the coolant out and overheating rather than running cold.

Sorry I spoke..jeez!

:bang:

Hehe - in the year and a bit that I have been on the forum this has come up countless times and seems to be different for every b!

At this time of year on a run (in the South of the UK) mine does not tend to get much above the 'resting' position, at best it will get to just below the 1/4 mark. If I leave it running outside it will hit the 1/2 way line or just above then the fan kicks in.

In the summer on a run the temp usually hits somewhere between 1/4 and 1/2, in traffic it usually sits just under 1/2 and the fan will kick in and out at will.

When I first bought that b I worried about this quite a lot, I went through a stage of convincing myself that the 'stat' had broken or that the temp sender switch was broken so changed them - the result, no bloody difference!

Speaking from experience, unless you are overheating or cutting out I would not worry too unduly about the running temp. The b's are not known for head gasket failures, under the bonnet always seems very hot yet the temp gauge will tell you otherwise!

If you really want something to worry about on your b peel back the plastic trim in the rear wheel arches and take a peek at what the road salt is doing to your hidden bodywork!

LittleRedB said:

If you really want something to worry about on your b peel back the plastic trim in the rear wheel arches and take a peek at what the road salt is doing to your hidden bodywork!

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Thats so sad & true.. Everyone should check this out..

Resurrecting an old thread. My B went to the garage today to get the knocking that has plagued my car for the last 2 years fixed. It's the offside driveshaft btw and I'm getting a new part manufactured as we speak.

Whilst I was there I mentioned the perpetual cold running and after a short discussion decided that replacing the thermostat would be a good thing.

I now have a heater that pumps out hot air and an engine that gets to operating temp quicker. Just what you need for winter. Not certain everyone with a cool runner needs to look to get this job done but I'm glad I invested ninety quid with MGC.

Thanks go to HP for pointing me to the solution.

Where does the needle on the temp gauge sit now?

Good question.

This morning on the way to MGC 4 miles away in a mix of 40mph and queues with an average speed of about 20 it got up to just under 1/4 by the time I arrived.

On the way back it got to above 1/4 much quicker than I have ever seen and moved between there and halfway. This was with the roof down and the heater on hot fresh air number 3.

I'm hoping that the oil being warmer on short runs will assist my dire fuel consumption. I know there was a 5w solution to that problem too but a new thermostat seemed more 'right'.

Sounds about right to me! My engine temp sits about half way between 90 degrees and 70 degrees.

Update. Fuel consumption noticeably better...