Heater Matrix Hell - What a day

[andrew_s46]

Evening All,

As per the thread title, what a day.

After living with a leaking matrix for some time I decided action needed to be taken to fix it. New matrix ordered and fitted today (along with new Volvo O rings) following the guide on here. As per many of the threads on here, not so much a difficult job but more fiddly than anything else.

The problems started after running the car up to temperature. Initially the job looked to be a success - A bone dry cabin floor with no sign of any leaks and a nice hot heater.

THE DISASTER: Up to temperature and running for around 15-20 mins all of a sudden a rush of coolant into the cabin at what appeared to be pressurised to some extent. Turning the car off and inspecting the leak appears to be coming from one of the pipes into the matrix.

Having read the tips on this forum I assumed that I had maybe not fitted an O ring correctly. I duly stripped everything off again and refitted. I must have completed this process about 4-5 times, each time being faced with ‘the disaster’.

I am at a loss as to how this can be fixed but really don’t want to admit defeat.

My initial thoughts are that the new matrix may have some kind of restricted flow causing a build-up of pressure, leading to coolant blowing out the joint.

Does anyone have an idea why this might be happening or any tips that I could try tomorrow?

Thanks in advance!

[Clan]

Originally Posted by andrew_s46

Evening All,

As per the thread title, what a day.

After living with a leaking matrix for some time I decided action needed to be taken to fix it. New matrix ordered and fitted today (along with new Volvo O rings) following the guide on here. As per many of the threads on here, not so much a difficult job but more fiddly than anything else.

The problems started after running the car up to temperature. Initially the job looked to be a success - A bone dry cabin floor with no sign of any leaks and a nice hot heater.

THE DISASTER: Up to temperature and running for around 15-20 mins all of a sudden a rush of coolant into the cabin at what appeared to be pressurised to some extent. Turning the car off and inspecting the leak appears to be coming from one of the pipes into the matrix.

Having read the tips on this forum I assumed that I had maybe not fitted an O ring correctly. I duly stripped everything off again and refitted. I must have completed this process about 4-5 times, each time being faced with ‘the disaster’.

I am at a loss as to how this can be fixed but really don’t want to admit defeat.

My initial thoughts are that the new matrix may have some kind of restricted flow causing a build-up of pressure, leading to coolant blowing out the joint.

Does anyone have an idea why this might be happening or any tips that I could try tomorrow?

Thanks in advance!

what ever the pressure the O rings shouldnt blow out , was it a genuine volvo heater radiator ? best get another and try that .

[byootox]

A simple test is to check and see if both pipes are hot going to the matrix as this would tell you if there is a blockage.
However even if the matrix was totally blocked it shouldn't do this anyway.
One thing you could check if it's an after market matrix is to compare the joint with the old one where the pipes connect up.
I had something like this years ago on an old Peugeot I eventually found that there was a slight difference in the diameter of the recesses where the pipe seals sat in.
It was a very subtle difference but enough to make it leak.
In my case it was a cheap s**t matrix.

[yeti76]

Sounds an odd one. Usually if you tighten the delivery pipe clamp against the o rings it seals well as previously stated.

If I recall the thread is an insert into the plastic retainer. Check its not just spinning, ie plastic cracked etc.

I'd be checking the inner bulkhead connectors too in case its running down. Its a push fit brass fitment like the bulkhead outer. These contain a stack of many o rings and washers. The washers in this area are known to break down over time.

I hope I have worded it in a way you will understand, but its late and i'm tired lol.

[Baffler]

Also something to consider...where was the original matrix leaking from? If from the o-rings it might be a good idea to flush out the original matrix and replace just the o-rings?

[andrew_s46]

Hi all

Well, I refitted the original volvo matrix back into the car on Sunday morning.

Ran the car for quite some time and took for a short run before building up the confidence to put all the trim etc. back on - so although it is a known weeping unit at least I can actually drive the car around until I can fix with a new matrix.

The aftermarket unit I bought was from eurocarparts. I suspect the unit has a minor design variation from oem or is just the one in however many that are faulty from the factory. Either way I feel quite nervous driving the car now having had this experience; expecting to get sprayed by hot coolant at any moment. Hopefully I will lose this feeling in time.

I managed to damage some of the fins when removing it from the car so unlikely I will get a refund now despite the problem with the supplied matrix not being linked to the fins.

I hope the original unit holds out for a while as I done fancy attempting this again.

[t5pete]

Originally Posted by andrew_s46

Hi all

Well, I refitted the original volvo matrix back into the car on Sunday morning.

Ran the car for quite some time and took for a short run before building up the confidence to put all the trim etc. back on - so although it is a known weeping unit at least I can actually drive the car around until I can fix with a new matrix.

The aftermarket unit I bought was from eurocarparts. I suspect the unit has a minor design variation from oem or is just the one in however many that are faulty from the factory. Either way I feel quite nervous driving the car now having had this experience; expecting to get sprayed by hot coolant at any moment. Hopefully I will lose this feeling in time.

I managed to damage some of the fins when removing it from the car so unlikely I will get a refund now despite the problem with the supplied matrix not being linked to the fins.

I hope the original unit holds out for a while as I done fancy attempting this again.

Just fitted mine from euro at the weekend I did notice a little weep from where it joins to the pipe work but I only did it hand tight and a little nip with the ratchet and all is fine I will inspect this coming weekend tho after seeing this thread and euro parts matrix

[OvlovS70]

Originally Posted by andrew_s46

Hi all

Well, I refitted the original volvo matrix back into the car on Sunday morning.

Ran the car for quite some time and took for a short run before building up the confidence to put all the trim etc. back on - so although it is a known weeping unit at least I can actually drive the car around until I can fix with a new matrix.

The aftermarket unit I bought was from eurocarparts. I suspect the unit has a minor design variation from oem or is just the one in however many that are faulty from the factory. Either way I feel quite nervous driving the car now having had this experience; expecting to get sprayed by hot coolant at any moment. Hopefully I will lose this feeling in time.

I managed to damage some of the fins when removing it from the car so unlikely I will get a refund now despite the problem with the supplied matrix not being linked to the fins.

I hope the original unit holds out for a while as I done fancy attempting this again.

Hello,
Get back onto Euro for a refund, i'm sure they will help.
As for the matrix with this being such a fiddly job I would only use a genuine part, with the work involved I would be looking for longevity.
Cheers

[byootox]

The two I done years ago with the problem were from Euro as well.
they were missing the packing foam to stop air getting round the edges of the matrix etc and the joints where the pipes mated up were slightly bigger and caused no end of problems.
Exact same story with a Rover 25 I done too.
On the other hand I've fitted a few from them that have been fine.
They were a fraction of the cost of the genuine one I suppose that's why .....

[yoda960]

I don't know what genuine heater matrixes for the 850 or s/v/c70 ranges cost, but when I enquired with Simon at FRF about a genuine one for my 940 it was something ridiculous like £400-500. Absolute daylight robbery, even Simon had a chuckle at the price.