C4 Grand Picasso 2015 (B78) Heater matrix part no

[Gabriel_M]

Hi all

New user (just donated as well, such a great forum) and I have a fairly recently bought C4 GP 2015 B78 1.6 Blue DHi EAT6.

I have no heat in the cabin though(just a little bit on the left side, drivers side is stone cold). The engine does not overheat and checked the coolant level, which is ok (looks brown and nasty - will replace as soon as the weather gets better).

First thing I would kindly ask: does anyone know the part no for the heater matrix? I would like to replace that as the first port of call, but can't find it on any of the usual car parts websites (ECP, Mister Auto etc).

Secondly: do you know of a good guide to replace the collant?

Many thanks in advance
Gabriel

[RichardW]

Hi Gabriel

Welcome along!

If you post up the VIN (it will hide itself) we can look up the part number for the matrix. However, it seems pretty unlikely it is blocked up on something this new, unless it's done interstellar mileage! More likely it is a fault with something in the electronic control system / one of the flaps. Pretty sure the matrix is accessible from the passenger foot well - if you pop out the trim panel under the dash you should be able to see the pipes, and feel if they are getting hot.

[Gabriel_M]

Many thanks for the reply.

VIN: VF7**************[VIN obfuscated, can be read by forum staff]

Yeah, good point about checking the pipes first, saves me having to take it out. Will reply as soon as I know more, but in the meantime, the part no would be really useful (at least it prepares me for the potential wallet raid).

Mileage is about 75k, by the way.

[GiveMeABreak]

Hi Gabriel

Thanks for your donation.

The original matrix part number was 1609730580, but this has been replaced with a new part: 9821299980, so I would use the later part number. The latest part number is currently priced at £182.63 inc. VAT direct from Citroen for a genuine OEM one. This is for item (1) on the diagram, which also includes the fittings 'B' & 'C'.

[Gabriel_M]

Thank you!

Do you guys know a good guide for replacing the coolant? Does not look straightforward looking at it.

[GiveMeABreak]

As you are a Donor, you can access the Resources section, where I have put up the coolant replacement guide for several engines.

The guide is exactly the same procedure, word for word for your car as it is for the DW10BTED4 engine - link below. The only difference it the coolant system pipes and parts will be different.

viewtopic.php?t=64036

This is the cooling diagram for your car, but otherwise follow the procedure above.

[Gabriel_M]

Hi all, sorry for taking some time to reply. Just to confirm the outcome, it proved to be (like for so many others) the heater matrix that is clogged.

Tried to clear the blockage/sediments using some radiator cleaner, but with limited success. It's now back on the car. I am trying to avoid paying for a new one (not cheap!) and plan to persist with trying to clear the old one. I heard something about using citric acid and hot water, left overnight in the heater matrix, repeated if necessary.

Any tips or feedback on this approach?

[LOONEYMAN]

hi im new to site just trying to figure it out,i have a 2017 c4 gp similar problem mine blows out hot air pasanger side [duel control ] and stone cold drivers side, ive cheacked the flaps in heater box threre fine coolant is fine, need to get it sorted before the cold hits again, thanks

[Gabriel_M]

I would remove the heater matrix and check it by pouring hot water (not boiling, so less risk to scald yourself) into it, if the bottom does not get hot within a few seconds, which I guess will be the case, then you have a clogged heater matrix, like I had. In that case, just buy a new one. Might be able to find one on eBay, new, for less than what Citroen charge (a lot!).

[LOONEYMAN]

thanks gabriel_m ill give it a try at weekend

[Lutino13]

Can someone tel me the part numbers for the heater pipes on this model please,new to site

[Lutino13]

Looking for part no of the 2 heater pipes,from thermostat to heater matrix,