There was a topic here about low temperature thermostats but it's pretty old and can't find the parts mentioned there.
Here is the old topic: https://www.fiatforum.com/cinquecento-seicento/25351-82-degree-thermostat-keeps-car-cooler.html

What thermostat people use to keep temperatures in line under heavy loads?

There was a mention of Halfords part HTK602 that fits Ford Fiesta 1.0 which innards can be made to fit Cinqs thermostat housing but none of the thermostats listed online are 82C. Are they still available and where to get one?

I'm worried that the original post in the linked thread is based on the assumption (post #4 ) that the thermostat opens at "96C". Even if that's a typo' and the poster meant to write "86C" then it's a bit misguided to go looking for a thermostat that opens any earlier.

You only want a thermostat that opens at a low temperature if the car is going to suffer a sudden and intense burst of energy.. such as a racing engine, on a race track. A 'stat that is too slow to open, or opens "late" will not open quickly enough to keep the engine at optimal temperature (i.e. the temperature will surge before the 'stat catches up with it).

Having said that, it only remains a real problem if the radiator and/or pump are not able to quickly cool the engine back down to normal operating temperature, for example, if a smaller radiator or an electric pump etc. has been fitted (racing car). The normal Cinq' road-radiator and standard pump is otherwise well up to the job of cooling the engine.

The optimal engine running temperature for your car (unless you changed the mapping to make use of a different temperature) is 88C. The thermostat is designed to start opening at 86C and is fully open at 90C. The fan will come on at 92C and stays on until the engine is back to 88C. Bear in mind the 'stat and the temperature sensor and the gauge are not 100% calibrated, so any of them can show a variance. 82-88C on the gauge is "normal" for Cinque.

I dunno why a 55C temperature reading (in the posts) is considered great. To me, that's just a knackered thermostat. Similarly if the fan comes on every few minutes in traffic, or stays on for a long time, then that suggests there is a problem in the radiator (air or f***ed) or the pump. If all that stuff is in good condition, the car cools fine.


Ralf S.

Just fit a new radiator. They are so cheap. They loose efficiency when they are old. Will likely solve the hot running problem imo.

You could even paint it black :O

you dont need a low temp thermostat.

i took my cinq on a trackday on one of the hottest days of the year and it was fine with a completely standard cooling system.

I wouldn't worry with a lower temp stat this is more turbo related where heat is a major problem and really are pushing the system to its limit and beyond fans do come on very reguarly on these a lower temp fan switch is more of use.

It's a stock 1.2 8v MPI with a new Cinq 1.1 radiator.
Even after 2km of rally stage the fan runs for 5 minutes straight. Seems too much

do you use a water and coolant mix or just straight water? do you have an oil cooler?

do you monitor that actual coolant temperature? may be worth doing that to see what is really happening. as long as it is not boiling over, you should be fine. is the fan already running when you stop, or is it only after a few minutes that it comes on?

I agree a low temp thermo is not required. Both my turbo cento's have run bone stock cooling systems and even with a red hot turbo right behind the radiator (granted i used some heat shield where possible) they never overheated. Even on track they didn't get over normal running temps. Prolonged periods on hard driving would get the oil super hot though, albeit never so hot the engine itself would overheat. The stock cooling system can provide plenty of cooling for your engine - infact my old sei turbo is now pushing triple standard power with its new owner from its little 1108 and its totally fine.

So I'd say make sure your cooling system is all in tip top condition, stick a new genuine thermostat on there, put a new rad on and give the system a damn good flush and then fit an oil cooler with thermostatic sandwich plate. You really want to get the thermostatic style or it will take forever to get the car warm up to operating temp. You could test the rad fan switch is cutting in at the right temperature too.

Coolant mix is a must here because of winters. No oil cooler.

Haven't monitored coolant temp but it seems slightly higher than usually if you push it hard.

Fan is already on by the stage end.
It's quite low speed rally which is more taxing on cooling system. Your average track day run provides much more airflow for cooling and this is why I'm worried.

Already replaced thermostat, radiator and coolant.

If you all say it's fine by the way it is then I must believe you.

an oil cooler will help for sure..

does your cinq have the vented wheel arch on the side with the rad? that is something fiat added to aid airflow through the rad and it does make a difference.

Other than that you could cut some of the front bumper out to let more air into the rad.

Another thing to note, and again i don't think it needs its as such but getting hot air out of the engine bay helps keep temps down more that getting cold air in if that makes sense. Try removing the rubber seal along the scuttle panel - when the bonnets shut this seals against it - without it there there is a nice gap for hot air to flow out of.

I would say as well that the cinq temp gauge is not greatly accurate. And unlike modern cars where the guage just sits bang on middle all the time its totally normal for the cinq gauge to go up and down a bit with outside temps and driving conditions. So long as the over temp warning light doesn't ever come of it should be fine, the cooling system is keeping everything within the limits

And again, not needed but the fan setup on the cinq is not fantasic, only covers part of the rad and has no shroud, would be easy to improve this setup.