Citroen C2 Coolant temperature readings using OBD.

[raz3n]

Hello,
A few months ago I got my first car.
A 2007 Citroen C2 1.4 VTR, unfortunately after just 2500km I had to do a head gasket repair due to coolant leaking.
I got a cheap OBDII elm 327 device to monitor my coolant temperature since I don't have a gauge at my dashboard.
Thing is I Constantly get readings of 105-106 degrees. I spoke to my mechanic which immediately told me to get it there,
I got there and with a laser temperature meter he started metering the hoses and the thermostat housing.
It was a 14-16 difference in degrees.
He was checking the main hose and told me that my fan should start when the hose is at 92degrees, I saw his meter jumping from 91 to 93 and the fan kicked in.
He Disconnected the temp sensor, so we can check if it's bad , and the water temp light on the dashboard came on in 15seconds and also the fan kicked in on it's fast mode.
He told me that everything looks fine and that the reading i get from the OBD device is not correct, mind that RPM and Speed are working fine,saying the same as the dashboard, with a small delay of some ms due to bluetooth connection.
Thinking of changing the thermostat because when we did the head gasket repair, we replaced the old plastic housing(and the sensor) with a metallic housing but we didn't for some reason swapped the thermostat.
I may overreacting but since it's my very first car and did a head gasket just 2500km on my hands, I started getting a little bit paranoid
What do you guys think on the situation?
Thanks a lot.

[raz3n]

Okay, so after a lot of reasearching since cars are a new thing to me in that level
and after I found a few diffrenet years service manuals online, I found the 2003 one which is the only one that has the table in the picture below

Spoiler: show

Also after seeing those posts explaining how a piloted thermostat works, by Forum adminstrator GiveMeABreak here
And reading a few other things online I came to the conclusion, without still knowing if my thermostat is piloted or not,
that the temperatures I see are pretty normal and that the ECU demands the coolants temperature to be 105 while on traffic , driving around in the city with stop lights etc.

I've seen people usually with VTS cars to change the thermostat to one that fully opens at lower temperature than the one specified in the manual
and by their sayings this lowers the temperature while driving around in the city,claiming that it may have a little difference on burning little more fuel.
I guess since the thermostat opens at lower temp then perhaps the 105 degrees can't be achieved so it stays cooler.
Will this make the engine perhaps last more or is complete unecessary change?

Btw here is my VIN VF7**************[VIN obfuscated, can be read by forum staff] in case any of the stuff members are interested.

[GiveMeABreak]

Ok, so yes you have a piloted coolant outlet housing and the following info is relevant to your vehicle that has Single Air Conditioning, piloted manual gearbox and a variable speed fan unit (chopper):

The engine coolant temperature sensor, installed on the coolant outlet housing, informs the engine ECU of the temperature of the engine coolant.

Temperature value

Info	Variable speed fan unit (chopper)
Engine	TU-ET3 and DV6 engine
Engine water temperature warning	118 °C
Length of post cooling	360 seconds
Temperature threshold for triggering post-cooling	98 °C 97 °C (TU5JP4)
Temperature for triggering of the cooling fan at slow-speed	96 °C
Temperature for triggering of the cooling fan at fast-speed	105 °C
Temperature for triggering of the cooling fan	-

Incidentally, I know this is a 2007 vehicle, but were you aware that there's an after-market campaign outstanding on this since 2009? It concerns:

C2, C3, C3 Pluriel, Dispatch - Software download

Reference: MBT.

So I would get your dealer to complete the software download - the work will be free of charge.

[raz3n]

?hanks a Lot for the reply.
I Didn't know that there's a campaign to software update the C2 along the others,but first owner were maintaning the vehicle at his local dealership until 2014 so they may already have done the software update.
I'll try to call my local dealership and ask them about it.
What was that software update about?

Based on the table you posted above I notice a few things that are different on my car.
Fan turns on at low speed at 105celsius ( based always on the ELM 327 OBD Readings) NOT on the fast speed, and tries to keep the temperature at 105 degrees and see them around 108-109 sometimes, I don't like it at all but I guess it's within the specs?
The only way for me to see the second fan speed kicking in is either to turn on the A/C or to remove the thermostat cable(the mechanic did this to check if the fan works as it should).
Also the table mentions TU-ET3 Engine, which as far as I know it's a 1400 16 valve engine and the TU5JP4 which is the 1.6 16valve engine, is this applicable on my case too?