V70 Air Con: Poor internal heat output

[oragex]

I've done a video how I fixed this https://www.youtube.com/watch?v=69ymGTqHxRw

If this doesn't work, may try to replace the cabin heater core (use a quality brand), seen here - the steering shaft can come now all the way for clearance, just make sure to mark it and have the front wheels sitting straight https://www.youtube.com/watch?v=37u_oQ0Q0Gc

[MarvinMitt]

Originally Posted by Dippydog

I'd hazard a guess that the matrix is at least partially blocked and most of the coolant is being "forced" to go directly from the inlet straight to the outlet without going through the matrix.

What in the coolant would cause such a blockage?
The heater matrix core pipes are about 6mm inner diameter, unlike the small openings of the multi-flow cores seen in the heat exchangers in the front of the car.

[oragex]

The blockage may happen inside the matrix, but also there is a tight passage inside the engine block. Limestone build up from mixing/rinsing the system with tap water (about 1-2 liters cannot be drained).

[skye740]

Thank you all, and I’m now convinced it is a matrix flow issue, as I’ve double checked dampers and internal temp sensor on the live data in VIDA.
I will add some type of cleaner into the rad system for a few days and then flush prior to putting it in for a t/belt change plus pump, and then see how it performs after that.
Worst case is the matrix will need replaced and cost another right arm in fluid plus matrix, best case I get decent heat after the flushes, time will tell.

[Black dog]

Originally Posted by Dippydog

I'd hazard a guess that the matrix is at least partially blocked and most of the coolant is being "forced" to go directly from the inlet straight to the outlet without going through the matrix.

This was my experience on my s60. New matrix (after market) never had a heater like it. Not too expensive and not overly hard to replace if you are willing to cut a small piece of the dash behind the glove box.

[barrybritcher]

Originally Posted by MarvinMitt

What in the coolant would cause such a blockage?
The heater matrix core pipes are about 6mm inner diameter, unlike the small openings of the multi-flow cores seen in the heat exchangers in the front of the car.

if tap water or low coolant mix was used it'll be rust flakes, if the coolant hasnt been changed for years it'll be like jelly in places

[staffy460]

Originally Posted by barrybritcher

turn off auto for a start, run it manually at max

this fix seemed to work for me much hotter thanks

[skye740]

Just an update for those who posted previously, I did a complete empty of the cooling system including taking off matrix pipes, I flushed out where I could and then poured my Molyslip rad flush into the matrix and topped it up with boiled water, left that for slightly over the recommended time, then flushed just that section, I then used another Prestone flusher in the whole system, left this in for a good few runs and flushed and replaced with water, the difference was instantly noticeable, up to 30c at footwell within a mile of driving.

It’s now had the T belt & Aux done plus pulleys etc, so no more issues for now.

Thanks again for inputs.

[oragex]

Originally Posted by skye740

Just an update for those who posted previously, I did a complete empty of the cooling system including taking off matrix pipes, I flushed out where I could and then poured my Molyslip rad flush into the matrix and topped it up with boiled water, left that for slightly over the recommended time, then flushed just that section, I then used another Prestone flusher in the whole system, left this in for a good few runs and flushed and replaced with water, the difference was instantly noticeable, up to 30c at footwell within a mile of driving.

It’s now had the T belt & Aux done plus pulleys etc, so no more issues for now.

Thanks again for inputs.

Another Prestone flush success. Good to hear