[Solved] Xsara Picasso 2.0hdi 2002 - Strange work of the cooling system.

Hello,
I have a problem with the cooling system in XP 2.0hdi 2002.
The car is after replacing the air conditioning radiator and water cooler.

In addition, the thermostat has been replaced with a new one.

I flooded the new coolant and started the car with the air set to the maximum warm air. When the thermostat opened, I added the missing liquid, but for more than an hour of work, the radiator fan did not turn on even once. The display shows two temperature bars all the time.
While the engine was running, I had the vent on the thermostat unscrewed. At first steam escaped and then from time to time drops of coolant.

I had a screw plug in the funnel screwed into the expansion tank for better liquid dispensing. So the tank was unscrewed all the time.
While I added more gas, the condition of the coolant in the reservoir increased to such an extent that it even appeared in the funnel.

When I turned the cap off the tank, after a while, when the engine was warmed up, the wires behind the thermostat and before were hard and the condition of the coolant decreased even to a level below the minimum mark. The level was before the maximum mark before.

I also tried to unscrew the bleed plug from the thermostat and immediately coolant spilled out. However, when I unscrewed the cap from the reservoir, the level of fluid rose rapidly until it began to flow out through the cap.

I tested the system for head gaskets by the method sold on Allegro, i.e. cork and wine scale. After pouring in the blue medium, the color did not change during idle and after adding gas.

What could be wrong? I wonder why the fan didn't turn on for so long.

Disconnecting the plug from the temperature sensor in the engine block immediately jumps all the lines on the indicator and information about overheating. After turning the ignition switch on, the fan is immediately switched to second gear.

Turning on the air conditioning turns on the fan in first gear.

I checked the white resistor mounted in the fan housing by touching the ohmmeter on both sides of the ends of the thermometer. Showed the flow. Same when I was touching the spring.

Are there any fuses or relays from the fan?

So how do you propose to fill the system and then bleed it?
It's good to know that it's hard to heat this engine. I thought it was very efficient.

If it fills the system cold, only if I am not mistaken will the liquid appear on the vent from the heater because but already on the thermostat is not because it is closed.
So it will fill the level in the tank to the maximum when the cold engine closes the cap from the tank and I start the engine. But should I set the airflow to work and what air should it blow warm and cold?
Then I wait for it to heat up to 2 lines and check if coolant starts flowing through the vent on the thermostat. When it starts to fly, I turn off the vent and turn off the engine.
I am waiting for the engine to cool down and verify the fluid level as below, then top up the tank level to the max.

I understand that it is difficult to bring the radiator fan to turn on at a standstill?

Maybe the sensor from the engine temperature shows the value wrong? Apparently on the dashboard will show 2 lines but in reality will distort? The sensor is original.

To know if it is already 90'C or not I need to connect best to a computer (lexia). The more I do not know if the engine in XP has a work at 90'C or not less.

In that case, how do I bleed the system? If I pour coolant into the tank and close all vents and the filler cap?

As I tried to bleed the system on a running engine (fluid filler cap open), I had the following effect:
As the fluid from the thermostat's vent began to slowly leak:

Then after a while it was like this:


At the beginning, when I turned on the vent, steam was coming out.
Unfortunately, I do not have a special tank as the constructor recommends.

I thought the system had to be bled while the engine was running, first at the heater and when liquid appeared, turn off the same at the thermostat.
From what you write, venting is when after emptying the system pour new liquid and you need to look at the vent from the heater when it appears, turn off the same with the vent at the thermostat. After doing this, I have to start the engine to warm up and then cool down. After that, see how much liquid is there and if necessary top up to the maximum level.

Is it normal that when the engine is warm these thick wires, i.e. the lower and upper from the radiator are hard that it is hard to press them?

Today I took the car for a short journey and so the level of fluid in the cold was above the minimum mark. I made about 20km of the road where the car got warm. After arriving at the place and waiting for an hour I checked the fluid level and it was almost on a par with the thread from the cork of the expansion tank. I wonder where the fluid level suddenly increased?

I do not know how it was before because I do not use XP every day but during the road at a speed of 80km / h the first line on the display appeared after 5km and the second line after 9km traveled.

Still, how could you explain to me how fluid will appear in the vent in the thermostat since it is closed on a cold engine.

Simply put, I want to drain the fluid through the bottom radiator hose, put it in place. Unscrew the air vents from the heater and the thermostat. Pour the liquid and observe when it appears in the vents, when it will turn on the vents and the expansion tank - start the engine. Set the airflow to the minimum temperature (with medium airflow) when the engine heats up to 90'C - as you wrote probably the fan from the radiator will not start (I am interested in what needs to be done to turn it on) and turn off and wait for it to cool down.
After this procedure, check the coolant level and if it is low, unscrew the cap from the reservoir and pour the liquid to the maximum level and screw the cap back on.



I wonder why the fluid level increased after the "short" ride.

I am also concerned about the resistor / resistor mounted to the fan casing which contains a thermostat and springs whether they are functional due to the fan not turning on. The engine worked almost an hour at a temperature of 33 degrees and the fan never turned on.

Hello Colleague, let me interfere in the discussion

emswisnia wrote:

I wonder why the fluid level increased after the "short" ride.

do as col [quote = "georgesgr"] writes or maybe so. the cabin heater is higher like the engine cooling system, so the liquid will not go uphill when filling the system and it will not replenish it at low speed, it remains good to chase it away or the alternative to go for some raid so that the front of the car was high and then fill up, a similar case in BM-helped from the arrow these are pressure systems as georges wrote you so on the open circuit when it is not vented there will be circuses.

Yesterday at night I left the cap unscrewed from the tank where the fluid level was at the thread level (so that the liquid could enter through the upper hose from the radiator - return).
Today I have connected to a computer and so:
At 77-78'C a second line appears on the display.
At 82-83'C the thermostat opens and you can see how the liquid is pumped through the thin hose from the radiator.
At 98'C the fan turns on in first gear and cools the engine to 91'C
The fan switches on each time the temperature reaches 98'C.

I tested the Lexia fan in first and second gear.
During the tests, the fuel temperature was 40'C
Outdoor temperature 30'C
The cooling fluid temperature usually showed a 0.5'C difference from the water temperature (e.g. cooling 91.5'C, water 92'C)

All the time snakes were able to be bent without much resistance - certainly lighter than before.
https://youtu.be/nc2EJENsjJc

The only thing I noticed is that you can hear hissing from the cork from the tank and after cooling sometimes a drop appears on the tank.

When testing on a cold engine, the fluid level was between the maximum and minimum lines. After starting the car, the level dropped below the minimum line but so that the sensor did not detect that there was not enough liquid.
When the thermostat opened, the fluid level increased to the state it was before testing.

If the thermostat opens and the liquid is pumped through the thin hose from the radiator, will bubbles or foamed liquid appear in the tank?

The system was bled.

Problem solved. Vented system. Additionally, the pipes from the expansion tank are replaced.