New owner 2009 207 1.4 thermostat/temp sender question

[admiral51]

Waited for 6 hrs or so so engine was cold, just gone out and started it up and left it on idle for 10 mins, both top and bottom hoses are heating up at same temp to touch wise.
Normally that would suggest to me stat is wide open, not sure on this engine due to sensors

[GiveMeABreak]

Are you over thinking this Colin? There are backup modes and warnings if things are not right, including fans engaging at speed if there is an overheating situation and cutting out of the A/C compressor. Unless the car is not performing, or throwing a wobbly, I would leave it until there are symptoms of a problem to be honest.

[David_CH]

Have taken it for a test drive and got some live test data which is now concerning me.

Hi Colin, which software you use for graph diagnosis ?

thanks
Dave

[GiveMeABreak]

The software is Diagbox, used by PSA. It has the ability to graph live data on many of the vehicle's systems.

[David_CH]

The software is Diagbox, used by PSA. It has the ability to graph live data on many of the vehicle's systems.

OH ! didn't have seen this menu on my diagbox.. when i reassemble my car i'll take a look. Do you know if it also log the data , to analyse it off the car ?

[admiral51]

Are you over thinking this Colin?

Now would i do something crazy like that
Actually i believe i was not thinking full stop to be honest. Thinking about it all the symptoms point to a faulty stat, and if its reference value to open is -40 degrees then it should be fully open all the time

As the boy wants it right he has ordered a new stat and temp sensor from main dealers, his money

Colin

[admiral51]

The software is Diagbox, used by PSA. It has the ability to graph live data on many of the vehicle's systems.

OH ! didn't have seen this menu on my diagbox.. when i reassemble my car i'll take a look. Do you know if it also log the data , to analyse it off the car ?

David the non graph screen shot is the where you can access the graph live data screen. On my screen in the bottom right hand corner i have 2 icons a pause icon and a graph icon, click on the graph icon and hey presto
AFAIK yes it creates a log that you can go back into and look back over off the car on the laptop that Lexia is installed on, i just do not have the tech know how to save/print the log file so i can post it here, i have to take a photo lol

Colin

[white exec]

Waited for 6 hrs or so so engine was cold, just gone out and started it up and left it on idle for 10 mins, both top and bottom hoses are heating up at same temp to touch wise.
Normally that would suggest to me stat is wide open, not sure on this engine due to sensors

Agreed.

[white exec]

The problem is that until engine temp got to 65 or so the gauge was not moving, then it decided to play catch up, finally matching engine temp at 76 degrees then over reading to 90 when engine was showing 80.
It then behaved and stayed at 90 until fans kicked in and dropped to 80 and then crept back up to 90 when fans had stopped.

I'm guessing that the gauge on this engine is driven from the engine ECU, rather than having its own sensor/sender. Is that correct? I ask, because this is typical of an out-of-spec Gauge sender.

[white exec]

Prepared to be shot down in flames here but most of you know my logic
We know that the stat is set to open at a certain high temperature to aid cooling, but would a stat need to be fully open at a significantly low temperature to stop coolant freezing ?

Never heard of that. Decent standard coolant will protect down to –35°C, and first priority is getting engine/heater temp up to working level, and maintaining it. Even a tiny crack/leak/opening of a 'stat can cause engine/heater temp to plummet in cold conditions and light/normal throttle.

[admiral51]

The problem is that until engine temp got to 65 or so the gauge was not moving, then it decided to play catch up, finally matching engine temp at 76 degrees then over reading to 90 when engine was showing 80.
It then behaved and stayed at 90 until fans kicked in and dropped to 80 and then crept back up to 90 when fans had stopped.

I'm guessing that the gauge on this engine is driven from the engine ECU, rather than having its own sensor/sender. Is that correct? I ask, because this is typical of an out-of-spec Gauge sender.

I believe the temp gauge is driven by a stand alone sensor on the thermostat housing and is actually doing its job with the live data confirming it reading engine temp correctly.
I am guessing the engine ECU uses a separate sensor for its coolant temperature reading but again i could be wrong as usual.
Disregard my idle thoughts about minimum temp stat opening, it was all down to me being confused over the -40 degree temp reference value, figured out if the stat has an opening value of - 40 degrees it will always be open

[white exec]

Senders common to many engines
- green one for Injection/Engine ECU
- blue one for Gauge
- brown one for cooling fan operation
This is reduced to two on some engines, with Engine ECU taking over functions of one of them.
Exact circuit diagram will confirm.

[admiral51]

In that case Chris you are right and wait for it ............ i am wrong lol
Def a Green plug on the thermostat housing

[white exec]

Do check the circuit diagram, though. Maybe another sensor elsewhere?

[admiral51]

Just a quick update on this one
Stat and temp sensor have been replaced whilst i have been away this past week, temp gauge is now showing in the region of 80-90 and bottom hose is staying cold until upto temp.
Tomorrow i will attempt to check the bleed process has been done correct with the engine below the stat opening threshold and trying to tell the ecu to open the stat, warm top hose cold/bottom hose i should get a warm bottom hose if the stat is tricked into opening ?
On a side issue if anyone has a little spare time and access could i have the wiring diagrams for the rear speakers for said car as both are not working, not sure if it is a head unit issue but guessing it is wiring related
Thanks
Colin