Engine: 70 R: Heater Matrix/Pipes

[sdg1970]

So I replaced the heater hoses today, block to matrix. They were getting a bit squishy, so definitely overdue. Locking lugs (yellow ones) supplied by PFS were rubbish and just wouldn't lock in, so I reused the old ones. Other than that, not too bad a job.

I've also got an aftermarket matrix I bought from PFS and was planning on fitting that tomorrow. Thing is, when I bought the car 4 years back it had a slight misting of the screen when the heater was turned, but because I couldn't be bothered at that time to replace the matrix I shoved a bottle of that magic sealer stuff in it. Not Radweld, but the stuff in the orange and blue bottle that in my experience does work very well. It hasn't misted at all in 4 years since and there's no obvious coolant leaks, smells or dropping level. Never uses a thimble full, ever.

I'm overweight, my knees and back are shot from 30 years lorry driving and the thought of contortionism on the wet, concrete pavement tomorrow trying to swap it out is just filling me with the question: should I leave well alone what isn't neccessarily broken.....? Thoughts appreciated Many thanks!

[capt jack]

As someone who's a bit too short for my weight, and not enamoured of discomfort, although a matrix swap on a P80 is relatively easy, it does involve a degree of bending and stretching.

On the basis that unnecessary repairs to an older car can sometimes cause more problems than they solve, especially where water is involved, I'd favour taking the "not broke so don't fix it" option.

A bit like our S70 the aircon of which gradually loses refrigerant over time. The options are a £50 refill every summer, or a complete strip down and replacement of all the gubbins, with no guarantee that it will all go back as Volvo intended. The car also had a slow radiator leak, and it was the local Volvo indy that recommended a proprietary additive rather than a new rad, on the basis that dismantling alloy pipes that have not been disturbed in 20 years is asking for trouble. Two years on the rad is holding up, and the car running fine.

I'd leave well alone but hang onto the matrix just in case.

Cheers

Jack

[sdg1970]

Cheers Jack, I'm inclined to agree.

[RollingThunder]

Just a caveat here, please bear in mind that the heater matrix in the 850s and x70s is a 'full flow' type.

Most cars have their heating controlled by a valve that restricts water flow into the matrix, thereby restricting the heat output. Ours doesn't have this arrangement - the coolant flows through the matrix unimpeded all the time, the heat output being controlled by flaps limiting the airflow through the matrix (and mixing it with incoming fresh air).

Therefore, if our matrix leaks - seriously leaks - then we will be losing coolant from the engine and will be unable to stop that flow unless we stop the engine. Once stopped, we can bypass the matrix by removing the heater hoses from the bulkhead connection in the engine bay and linking them together. But in the meantime, the coolant will flow...

I recently changed the matrix in my 850, and while it was a little awkward, it is probably the easiest heater matrix to swap out. I am also under-tall, have a bad back and high blood pressure, but I managed to do it without finishing myself off

I changed mine because I was also getting the screen fogging first thing, which indicated some coolant loss via the matrix. This is what mine looked like when I removed it -



As you can see, it was starting to go in several places - in fact I was surprised at the number of tubes that were starting to fail. I highlighted the main areas of deterioration, but there were many many areas that were showing signs of leakage as you can see. I suspect that your matrix will be similar, and so I'd recommend that you change it rather than leave it be - simply because it will fail at some point, and changing it gives you the choice of when to do it. I did mine because it was in the summer and I didn't want to be faced with doing it on a cold wet windy winter's day!

[sdg1970]

Many thanks for that - duly noted! I'm going to leave it until the Spring. If it goes meantime, I'll have meself to blame. Cheers