PSA electronic thermostat operation

[Valex76x]

Ah, yes, I can see from your profile

Just a picture of the two oil catch cans

And the pre filter (bugs catcher) on the filter intake

All the rest is pretty much original .
Sorry that I posted all this on the completely wrong section of the forum
Thank you for your support and sharing your knowledge.

[xantia_v6]

BTW, does your catch can catch much? And what is the quality of what gets caught?

[Valex76x]

In total is about 20-30 ml every 5000km. I find a little more oil on the right side breather can. I have a strange can there , a copy of the Mann+Hummel provent 200 with a drain hose that exits near the back of the front left wheel. The hose is close on the bottom and I can drain the oil from there.
The oil is mixed with water (the condensed vapor) and some yellow emulsion. Similar as what you can see on this video:


I do 25.000km a year. The car has almost 150.000km. Bought with about 90.000Km. I replace the oil by myself two times a year with Total Ineo ECS 5W30.

[gwest]

I have had two catch cans installed on my 2013 DS5 THP155 for the last 4 years and in that period have only covered about 14k km for 6 oil changes. Up until the last oil change the RHS can (to intake manifold) collected 5-12 times as much fluid as the one on the LHS on the line to the turbo. The combined amount of fluid has averaged 245ml/10k km but has been as high as 525ml. From early on I had a noticeable smell of crankcase fumes when I parked the car in the garage after a run. Recently I observed that the top of the platic engine cover is oily and it appears to be coming from the cover over the PCV area at the rear. On my last oil change I was surprised that I only collected the equivalent of 70ml/10k and that the RHS was only twice the amount of the left. I am wondering if the leaking cover could be the cause. And where exactly is the leak coming from- is it the bonding of the cover to the PCV assemblies below? In which case it might be possible to crack the cover off and reseal it with silicone?

[xantia_v6]

It is likely that the cover has distorted and is not pressing on the rubber seal. The rubber seal will also have lost elasticity.
I didn't have any success adding silicone to the joint, but a new top cover and seal did fix the small leak that I had.

[raz3n]

Some further info to explain how it is regulated:



"C" Partial load.
"D" Full load.
"T" Coolant temperature (°C).
"t" Time.

Time	Operating phase	Description of the operating phase
t0 and t1	Partial load	The engine management ECU does not activate the piloted thermostat regulation control; The regulation of the engine coolant temperature is performed at 105% to guarantee a saving in fuel consumption
t1 and t2	Full load	The engine management ECU detects a full engine load and controls the opening of the piloted thermostat by means of the internal resistor which melts the wax, simulating a temperature of 105°C. The engine coolant temperature decreases and stabilises at a temperature of 85°C
t2 and t3	Full load	The engine cooling is regulated at an engine coolant temperature of 85°C, to avoid an excessive engine operating temperature
t3	Partial load	The engine management ECU detects a partial load and no longer controls the activation of the piloted thermostat internal resistor ; The controlled thermostat again regulates the engine coolant temperature at 105 °C

Coolant temperature sensor
The NTC (Negative Temperature Coefficient) resistance value "R" changes in relation to the change in the temperature "T":
When the temperature "T" increases, the resistance value "R" decreases
When the temperature "T" decreases, the resistance value "R" increases



"R" Resistance ( ohms).
"T" Coolant temperature ( °C).

Temperature (°C)	Resistance (OHMS)	Tolerance(s) (in °C)
-30	88500	± 0,97
-25	65200	± 0,97
-20	48535	± 0,97
-15	36475	± 0,97
-10	27665	± 0,97
-5	21160	± 0,97
0	16325	± 0,73
5	12695	± 0,73
10	9950	± 0,73
15	7855	± 0,73
20	6245	± 0,73
25	5000	± 0,57
30	4028,5	± 0,57
35	3266	± 0,57
40	2663,5	± 0,57
45	2184,5	± 0,57
50	1801,5	± 0,57
55	1493	± 0,57
60	1244	± 0,57
70	876	± 0,57
80	629	± 0,34
90	458,9	± 0,34
100	340	± 0,30
110	255,6	± 0,30
120	194,6	± 0,30
130	150,5	± 0,70

Hello there and sorry for reviving such an older thread.
Do you know if this is how the thermostat/temperature sensor operates on Citroen C2 VTR?
I Did a head gasket repair, and got an elm 327 to monitor the coolant temperature.
Since then I'm trying to figure if the 105 degrees I get on Torque app while driving into the city and the ~90 degrees while on highway are correct.
Full story here if anyone interested. viewtopic.php?t=83321

Thanks

[xantia_v6]

The controlled thermostats have 2 wires for the temperature sensor and another 2 wires for the control (heater). Sometimes the 4 wires are in a single connector and sometimes in 2 separate connectors.

[raz3n]

The controlled thermostats have 2 wires for the temperature sensor and another 2 wires for the control (heater). Sometimes the 4 wires are in a single connector and sometimes in 2 separate connectors.

Hmm looks like it's the same.
I have 2 wires from the green sensor and I think 2 wires from the blue sensor which If I recall right they end on the same connector.
So I guess, it's the same system with mine and it's fine to see 105degrees while driving in the city?


Edit : will have a look and report back because I think I made a mistake thinking I have a blue sensor, while I do not and I think I mixed that with another blue connector.

[adhi89]

Hello all,

Found this thread really interesting and i think someone can really help me out here before i have to pay at garages before they can even identify the issue.

So the story is following,
I own a Peugeot 5008 1.2 Pure Tech 2018 with EAT6 since August 2024. As a second car, i use this mostly on family trips only (short as well as long).

In Dec some relatives visited me and i could use 7 seats for over 100km trips. Found out that there is like half a liter less coolant in expension Tank. I did a refill and left for Trip. All went fine. Temp Guage remained at 90°C as always. Highway speeds upto 130km/h...

On 28th January 2025, on a 5km trip i saw a sudden increase in Temp and warnings to stop car etc.
As i was less than 1km away. I drove slowly to home and found out that all coolant spilled out of coolant Tank Cap. Apparently the pressure rose up and the Cap let it out.

After some research on Internet replaced the Tank cap with one from FEBI, filled the spilled out coolant with water (around 1.5liters) and tested the next few days.

From 28Jan to 11Feb, did multiple trips upto 20km long in one go to gain confidence again.

And untill yesterday all was good.
Just yesterday same thing happened. Same short trip, the level rose up, warnings on. Drove slowly back to home. And saw coolant spilled out of expension Tank cap again.

Can someone narrow down it for me? Where shall i start?would be highly grateful.

P.S. pic attached is from 28.Jan but its the same as yesterday.

BR

[GiveMeABreak]

You realise that that is an EXPANSION tank? It is supposed to contain air and it's purpose is to allow the heated coolant to expand into the tank like a cushioning effect and prevents the system from becoming over-pressurised as the coolant heats up and expands.

So it should not be filled up at all - and should never be above the MAX level indicated. Have you been filling this up which has caused it to over-pressurise and release coolant via the safety valve?

[adhi89]

You realise that that is an EXPANSION tank? It is supposed to contain air and it's purpose is to allow the heated coolant to expand into the tank like a cushioning effect and prevents the system from becoming over-pressurised as the coolant heats up and expands.

So it should not be filled up at all - and should never be above the MAX level indicated. Have you been filling this up which has caused it to over-pressurise and release coolant via the safety valve?

Hi there,
Yes i know its an expension Tank and should not be filled up more than Max Marking. So yes i followed it. The attached picture is from the moment car got heat up as per warning on instrument cluster . And as it pushed out the coolant, thats why you see the Tank full of fluid. You can see some shiny fluid marks on Tank surface and below. So it was pressurized condition. The next morning the water went to engine and the Tank was empty. Then i filled it up with water. Around total 1.5 liter came in it in two times since this happened.

Now same thing has happened after around 120kms and 12 days gaps yesterday.

Same happened last night in a 5km trip. Full tank and no coolant in engine, instrument cluster saying Engine hot and fan running louder even after engine off for a minute.
I left it cool over night. Today morning water from expension tank was gone back in engine and i could fill in around 750ml in expension tank. Kept engine start for 25mins. Engine temp didnt even reach 50°C. And the water in expension tank remained till where i filled it up.

Gave up and turned the car off. Hopefully next time i do a short trip this 750ml will go to engine and i have to top it up once more to fill the system completely.

I am doubting Thermostate or coolant Temp sensor which doesnt let water flow into engine and then cause excess pressure to push coolant out of Cap.
Or it can be something big too

I just love my car and i am very upset

[PaulC5]

Why is the colour of the tank black, does it have oil in it ? Possibilities include the thermostat is not opening (check if the radiator top hose gets hot) or the head gasket has failed.

[xantia_v6]

If the black tank is caused by engine oil getting into the coolant, then it could be that the cause is failure of the oil to water heat exchanger (which I beleive to be fitted to this engine).

You did not mention whether the radiator fan was running at full speed while the car was overheating.

If this engine has a controlled water pump, it is possible that there is a failure of the pump drive mechanism.

[adhi89]

Why is the colour of the tank black, does it have oil in it ? Possibilities include the thermostat is not opening (check if the radiator top hose gets hot) or the head gasket has failed.

So it had that dark red Coolant in it. I dont think there is Oil in it. Now its pretty much water so it has diluted alot.
Well tiday after 25mins of car start with heater ON, the radiator Hose remained cold, temp didn't even reach 50°C and water didnt went towards engine either. Dont know if its some issue with Thermostat jammed closed or it was due to 0°C outside temperature.

[adhi89]

If the black tank is caused by engine oil getting into the coolant, then it could be that the cause is failure of the oil to water heat exchanger (which I beleive to be fitted to this engine).

You did not mention whether the radiator fan was running at full speed while the car was overheating.

If this engine has a controlled water pump, it is possible that there is a failure of the pump drive mechanism.

Well yes, the Fan was running louder than usual when the car got those warnings. But dont know if engine was really hot or it was just because of wrong values from some temp sensor. And because of that the Thermostat also didnt open. We have here around 0°C outside Temperatures.

Engine is EB2DTS, if it helps. 1.2 with 131hp EAT6 Gearbox.