How-to correctly replace ENGINE COOLANT and BLEED the system on a 2.0 BlueHDI 180 car

[JimmyTulip]

Hello,

I have a C5 Aircross from 2019 with the 2.0 BlueHDI 180 engine.

VIN: VR7**************[VIN obfuscated, can be read by forum staff]

I want to replace the engine coolant in the near future and I am looking for the correct procedure.

As far as I know the car has a map-controlled thermostat and there is a specific procedure to bleed the coolant system and get the air out.

Lexia/Diagbox is available and I am able to connect to the car.
Additionally I would have hardware available to vacuum fill the coolant system, if necessary/recommended ...

Some time ago, when I was looking around with Diagbox connected to the car, I remember stumbling across a menu item/action to bleed the cooling system. - I did not try it yet ofc ...

I have NOT bled the cooling system on ANY Citroen and I do not know, if there are any bleed valves and how to use them?
I am also curious, if I have to turn the HVAC/heater on or if this is done automatically by the Diagbox procedure ...?

If available, an extract of the workshop manual with pictures on this subject would be more than great!

I was looking for information on the topic on the internet, but I was not able to find quality information. For example guys on YouTube-Videos did not use Diagbox for it and therefore I assume they are not doing it right ...
When I was looking for used cars some time ago, especially the C5 (X7) with the BlueHDI 180 engine, I came across at least 3 cars that had engine problems due to overheating. (one had a replacement engine, one had replacement cylinder head, one mentioned to have overheating issues, ...)
Therefore I am quite scared and I want to do it right!

Thank you very much for your support!

[GiveMeABreak]

I'd be happy to put up the correct procedure in the resources section, but this will require a membership upgrade to access. If interested, see below:

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[JimmyTulip]

Hello Marc (@GiveMeABreak),

Is this the appropriate procedure for my vehicle that you mentioned? -> C5 X7 DW10BTED4 Draining / Refilling Coolant

It contains a section for "Diesel engine Euro 6 ONLY", but it does NOT mention anything about Diagbox and starting the degassing procedure. This makes me feel uncertain.

I am also very unsure about the bleed screws. How many of them should be on my car and where are they located?

I found a bleed screw near the heater matrix. (#1 in the picture)
Should there be another one located near #2 in the picture? I did not see anything just by looking, without disassembling anything...

Thank you very much!

[GiveMeABreak]

Hi, so no, please ignore that particular procedure, as there are specific operations required for the DW10F engines that use the diagnostic tool to check the correct positioning of the bleed valve and provides guidance during the procedure.

I currently don't have this in the resources section, so it will take me some time to write it up for you. Leave it with me and I will put a link here to it when I've completed it.

[GiveMeABreak]

Ok, so here is the procedure, please make sure you refer to the correct sub-sections for your particular engine.

DW10FU, DW10F, DV6F & DV5R - Draining, Filling, Bleeding Cooling System

[PaulC5]

Out of interest for my benefit (and possibly others), does the diagnostic tool do anything that can not be done by keeping a foot on the accelerator pedal ? Also, what is the bleed valve that the diagnostic tool needs to check the position of, I guess it is not just a bleed screw/cap as on older cars ?

On our 308 1.5 hdi the dealer replaced the coolant as part of its 4 year service, the schedule is for just a check but they replaced it anyway so not a job I am expecting to do.

[GiveMeABreak]

Yes, the diagnostic tool requests the Engine ECU to report / check valve positions and also provides the step by step guidance at the appropriate time.

[JimmyTulip]

Hello Marc (@GiveMeABreak),

Thank you very much for providing the instructions and especially for the effort and work you put into it!
Unfortunately, there are still a few minor uncertainties. Perhaps you can help me clear them up:

1. Can I perform a type of "dry-run"/simulation and start the degassing-procedure in Diagbox without prior touching the cooling-system without negative side-effects, so I could hassle-free get an idea on how this works?

2. Where/What is the "de-aeration chamber plug" mentioned at the beginning of the provided instructions?

3. The procedure mentions: "Open the bleed screws located on the coolant outlet housing and the heater pipe".
As mentioned I have found the bleed screw on the heater pipe. Where can I find the other one?

4. Are the bleed screws only for draining the coolant and filling it the classic way without vacuum?
Is it not necessary to open the bleed screws at all when the engine is running?

5. If only the lower hose on the radiator is removed for draining, i think only the large cooling circuit is emptied.
What are the options for draining as much old coolant as possible? The procedure mentions: "Drain the cylinder block" ...?

Thank you for your assistance!

[GiveMeABreak]

This operation is really intended for the dealer technicians, as they would have had the training to be honest and because of the model variations, ancillary equipment may be located in different places on different vehicles. I can't really comment on the detail as I have mine done at the dealers. I certainly wouldn't do a degassing dry-run without being at the stage where you have the equipment required already connected - as this may cause an internal problem if the system is fighting against itself.

[JimmyTulip]

Oh, that's very unfortunate, but I actually feel very close to the goal, and therefore I would at least like to find out, if my car has a second bleed screw?
I suppose the bleed screw is replaced by the mentioned electronic bleed valve ...?

[kantica]

One bleed screw must be on thermostat housing.
Take a look at this video (start watching at around 16:30) -

[JimmyTulip]

Hello,

One bleed screw must be on thermostat housing.
Take a look at this video (start watching at around 16:30)

The mentioned YouTube-video is indeed very familiar to me!

But unfortunately the car on the video seems to be different to mine.
Yes, the YouTube's car has the mentioned bleed screw on the thermostat housing. Below are two stills from the video:

Here is a photo of the thermostat housing of my car:

As you see there is a hose instead of the bleed screw.
I followed the course of the hose and it ends up in the expansion tank:

All in all I have doubts, that the process of degassing shown in the YouTube-video is right, because he does NOT use Diagbox for it! (as mentioned in the workshop-manual procedure Marc posted ...)

This specific YouTube-video is also the reason for my question #4 if it is necessary to open the bleed screws when the engine is running!?
The workshop manual mentions to open the bleed screws only for draining and closing them of course before vacuum filling.
For degassing the coolant system they are not touched anymore, when working after the procedure.

The guy in the video is making such a big mess opening the bleed screws while the engine is running and I don't think this is necessary.
He mentions, that he is doing that to get out all of the old coolant. I also think there must be better ways doing this. The workshop procedure mentions to "Drain the cylinder block (if necessary)", but I don't have further informations on doing that.

@kantica: Übrigens schöne Grüße aus Kärnten nach Wien

[GiveMeABreak]

Also note that there are operations SPECIFIC to the engine variant - as detailed int he procedure, some use the diagnostic tool, some don't.

[kantica]

Ok I see now, your bleeding point is directly connected to overflow. I would just follow the procedure in Diagbox and do the change. I just looked only how the thermostat housing looks like, and it seems that in your case thermostat is replaced with motorized mechanism that opens and closes the ports to/from engine - so it is most likely controlled by the ECU. Heater core is directly connected to the cooling system without any valves (set fan to the slowest speed, temperature control to HI).
No need to fuzz about draining engine block, just replace coolant / flush the system few times in a row.

@JimmyTulip: LG nach Kärnten

[Fletcher2002]

Ok, so here is the procedure, please make sure you refer to the correct sub-sections for your particular engine.

DW10FU, DW10F, DV6F & DV5R - Draining, Filling, Bleeding Cooling System

Hi I am new to the forum, and looking for the correct way to bleed the coolant of my DV6F engine. On the internet there is a lot of conflicting information if a diagnostic tool is required or not. The link in this message seems to have the answer to this question, but I am not " You are not authorised to read this forum." Is it possible that someone can give me acces to this document or can give me the liberating answer i am looking for?