Hi everyone

My problem with my Fiat siena 1.6 16v 2003 is my fan works intermittantly.
On some accassions in traffic my temp gauge is at the half way mark when it goes slightly higher i can hear my fan engage on high speed and temp gauge decreases but on other accassions i cannot hear the fan engage and the temp starts to increase higher and higher i force the fan on my engaging my aircon or switching the ignition off. What could be the possible problems. I have changed the fan relay.

Temp. sender on top of thermostat housing.
Or large sensor in radiator, lower left side.

Thank you Peter . I have had my ECU read result: no errors , but the actuators on the diagnostic tool was not able to switch on the 1st stage fan,:bang: only 2nd stage fan seem to work although we did hear the relay click but the fan did not engage, any idea what the fault could be?

Hard to tell from a distance.
Maybe a new wire from the relay to the fan might work..?
I'm having exactly the same problems with a complete different car ( Pontiac Firebird V-8), it can drive you mad.....!!

Hi peter
Coincidently, I noticed yesterday that my car is heating up more then normal.

Generally without the aircon on, the temp needle stays a shade below the half way mark or exactly on half. Once it reached there the second fan used to get activated and the temperature used to drop down a few points and the same cycle continues

Yesterday there was loads of traffic and I noticed the temp needle going three or four points above the half way mark and then maybe the second fan activates and it comes down to half. But unlike before it creeps up again in no time


I also did what mr. Reddy did I.e. Switched the aircon on forcing the second fan to be on all the time. Then it stayed at quarter mark like it always does with aircon on


Is this a sign off failing thermostat? In my case the temp needle does not how beyond 70 percent mark, probably 60 to 65 and then comes down. Still it's more hot then normal and I know engine heating is no good for the engine


Can you advise me what should I do about it? Do I need to change the thermostat or need to check something else as well?


By the way thermostat costs a bomb here. Approx 100 USD (US dollars)

I wouldn't worry, the temp chauge is not that accurate at all.
My car does occasionally about the same, it all depends on outside temps and traffic conditions.
The temp. needle is controlled by the sensor on the thermostat housing, and the fan(s) by the sensor in the radiator.
By turning on the A/C you are actually raising eng. temps, that's why the fan comes on...
To lower engine temps, turn the heater and blower on instead...
And for inexpensive parts, Ebay and Paypal are still your friends, no matter where you live...

Peter Pick-Up said:

I wouldn't worry, the temp chauge is not that accurate at all.
My car does occasionally about the same, it all depends on outside temps and traffic conditions.
The temp. needle is controlled by the sensor on the thermostat housing, and the fan(s) by the sensor in the radiator.
By turning on the A/C you are actually raising eng. temps, that's why the fan comes on...
To lower engine temps, turn the heater and blower on instead...
And for inexpensive parts, Ebay and Paypal are still your friends, no matter where you live...

Click to expand...

Hi Peter
I did turn on the heater and blower initially but since it did not make any difference, I decided to switch on the AC.
I was not sure if fan was going on second speed and there was such a bad traffic jam, that it was not possible for me to park the car and check

I very well agree with you that ebay and paypal are my best friend. But the issue is Indian customs and no parcel can come without passing through indian customs
For them, a paypal payment receipt is not a legal proof of payment. They think every person importing is having an underpriced invoice, ask for 100 documents when you clearly state that the product imported is for personal use
In all this first they end up taking months to clear the package and second make us pay a lot else wont release the package
I can very well challenge their calculations but that in itself is a very big task and would need endless visits to their office and lots of patience

Okay now about the car, I did check the coolant level and its fine
Another thing i found out that once aircon is switched on and then switched off the fan does not go to the first speed which it ideally should go
Without aircon the fan is mostly on first speed and just goes to the second speed for a few seconds and that too occasionally

It does go back to running at first speed but after a long long time.

Now is this also a thing i need to look into and get it rectified? Or is it OK
Ideally this should decrease fan motor life as it will run on higher spped for a longer time even when not needed. But my car does not do much running

About the temperature being higher then it has normally being, I will keep a close look on it whenever the car is run. If it goes down once it reaches a certain temperature, I will not worry for now and see how things are once the weather becomes a little cooler after maybe 30 to 45 days

If its a calibration problem, its frustrating because it always makes us worry while going far away. Who would want to be stranded with overheated engine and also the risk of blown head gasket