850 Heater Hose/Matrix Junction
 

After having a wet passenger carpet for long enough, I now have the time to begin sourcing the cause. I assumed heater matrix failure, and the staining on the sound deadening and matrix box seems to confirm this. However it didn’t seem likely that the sound deadening, which was soaking, would just be wet from here. And so when I investigated further, I found that the pipes down towards the heater matrix are dripping wet, almost like condensation, but these are notably dripping water, and the sound deadening, which is foam backed, is absolutely soaking wet.
I’ve been looking and wondering if the heater matrix junction, which is where the coolant pipes pass through the bulkhead and into the cabin, is perhaps the culprit. The pipes from engine to junction under the bonnet were replaced a couple of years ago (not by me), and I wonder if it has disturbed this.

Either way, it’s either going to be the seals or the heater matrix bulkhead junction itself, and my biggest issue is that I cannot seem to find one anywhere in the U.K.
Every one I see for sale online is from the USA, which obviously adds time and cost. Volvo dealers here in UK are mostly closed at present.

Does anyone have any ideas, or indeed where I could get one from, or is the USA possibly my only option?

I took delivery of a load of parts for my 850 on Thursday from parts for Volvo online, they are open and they appear to list all pipes required to supply a heater matrix. Worth taking a look and calling them.

As above re PFS & FRF for parts - the most likely cause of the leak is the silicone seals, they have a tendency to perish/degrade overtime and may well not have been replaced when the hoses were replaced - NB it is recommended to replace the unions at the same time.

There is also the possibility that the hoses were not seated correctly in the unions when they were replaced.

Thanks all - will see to it on Monday. I assume that the junction itself will be ok to reuse, and I’ll just replace the relevant seals and unions attached to this?

There are a plethora of threads on this issue over at matthewsvolvosite. They refer to it as the firewall coupling - there are several OE fixes, as well as upgraded methods to eliminate the weakspots (that still exist in the new parts).

I’m wondering if it’s worth my while in the meantime draining the coolant, as I’m fairly certain that it’s leaking from the junction area, to stop it further dripping into the footwell. Job for today methinks.

UPDATE - after contacting FRF, they have the relevant part, which includes all washers and clips etc, for £36 plus postage (with C3 forum discount applied). Always impressed with their level of service and would highly recommend them.

I've always found FRF to be very helpful and have always provided excellent customer service and support. :thumbs_up: