Heater Matrix Radiator core flush on a Volvo V70 S60 XC70 S80 D5

[@sirobb]

Nice job and great preventative maintainence but if you haven't yet, definitely clean out all of the caked up fluff in the cabin temperature sensor grille directly above the drivers side temperature knob. If the CCM thinks the cabin is warmer than it actually is, you won't get the correct heat output as it thinks the cabin is already up to temperature. Likewise, it will pump out excessive cool air in hot weather as the cabin sensor is over reading and not reflecting the cooling that is taking place. Dice and Vida can also tell you the live cabin temperature data from the sensor so you can confirm if the temperature the system sees is credible. On a stone cold car, before starting, the cabin temperature should read roughly ambient temperature unless it's been sat in direct sun in which case the reading will be higher until the system is running. Depending on the cabin temperature selected, the system will automatically allow hot or cooler air into the cabin to raise or lower cabin temperature to the selected value. This can only work correctly with a free flowing system, correctly functioning thermostat and working cabin and evaporator temperature sensors.

[@TheRepairer]

Thanks for the detailed comment, when I made the video I didn’t know about the cabin thermostat! I just did the heater matrix flush as it has noticeably improved the heater output for many vehicles I’ve owned over the years including this one.

[@sirobb]

@@TheRepairer Sure, old school mechanical/physical fixes can improve heating performance but just bear in mind that there are more sophisticated electronic reasons which can have a significant effect on the heating and ventilation system. If just a flush completely fixed your heat output problem, that's a great result but someone may come across this video and not have the same outcome because their issue lies with the more in depth electronic control side of the system.

[@paulmcconnell7445]

@@sirobb & The Repairer. I dont do anything on my V70 without checking you two havent already posted something about it first. Quality stuff chaps. Keep it up! I am chasing a poorly performing heater. I have a SiRobb Dice + Vida kit and am getting quite familiar. However can you confirm where I can read off the Cabin Air Temperature sensor output? My order of attack for this issue is 1. Clean out fluff in the cabin temperature sensor grille first. 2. Change cabin HEPA filter (folks on the web seem to be pointing finger at this a lot) 3. Do heater matrix flush as per this vid 4. Do coolant flush and replacement as per SiRobb vid. Does this sound like a sensible plan of attack?

[@TheRepairer]

Yes clean out fluff first as it’s the easiest job, I suppose a thermometer at the air air vent would be a good way of measuring the output I’ve no experience with Vida.

[@paulmcconnell7445]

@@TheRepairer Good idea on the thermometer. The Vida question was aimed at SiRobb really. Thanks

[@myslecinaczej8674]

Everything is helpful ...except the water flooding the engine! You could put a pice of pipe on the firewall hoses and connect the water pipe first,m before you feed it.

[@TheRepairer]

Good point, I couldn’t find a suitable piece of hose in the garage to join. I would have preferred to flush it that way though, ideally with clear pipes for maximum visibility of the debris exiting the heater matrix.

[@myslecinaczej8674]

@@TheRepairer Thanks for responding to my comment! Keep the good work (with some improvements :) )!

[@jefhaas7062]

The sensor in the car is also dirty with dust you can carefully blow the dust out, but be careful the sensor dont brake because its a really thin wire . You ca see the the Dirt in the small vent, below push mem button this also helps

[@zenoelea8239]

@@jefhaas7062 Can of computer compressed clean air duster works well. Do this when you replace the cabin air filter.

[@daviej95]

This could be helpful, my passenger cockpit heater isnt working but driver side working fine so reckon control maybe at fault.

[@corkbikeshed9465]

Hi there. I have the exact same problem as you. Did you find a fix? Any advice much appreciated.

[@corkbikeshed9465]

Only cold air coming through to passenger side

[@Justafella30]

Faulty Blend door motor remove glovebox behind there off to the right you’ll see a small black motor remove 2 screws and pull away no need to unplug electrical the manually turn the flaps by hand you should feel it turn and hear the flaps you should then get heat until you replace the motor or if like me leave it constantly on hot through winter then remove glove box again to manually adjust to cold through summer. I could just replace the motor and stop being stubborn but doesn’t bother me enough now that I know I can at least keep warm in winter and cool in summer takes all of 15-20min to do once you know how to.

[@chrishall7258]

very useful thanks!

[@zenoelea8239]

My 2005 D5 has a different clip, there are two small plastic legs the have to be nipped together that retract the pipe retaining lugs, you then twist and pull while nipping the legs together.

[@TheRepairer]

Interesting information, thanks for sharing.

[@alarynxforditoiroda4785]

Nice Job! I will try to flush it the same way, but my car is an XC90 V8. So I have ABSOLUTELY no space to get access to those 2 hoses! Only if I'd remove that thick black, horizontal stabilizing metal thing. I saw, you were working UNDER it, which is not possible in my case... so what do you think? Can I remove it? It's only 4 hexagon nuts and bolts. BUT I'm afraid there is some mechanical stress and maybe I'll not be able to replace that black stabilizing "thing" after removing it .. OR? If YES, I'll do it tomorrow... What do you think? If you (as a mechanic) say, I can remove it, I can do it easily... I just have to be sure I can replace it with no big problems coming up... PLEASE ADVICE! THANK YOU! And thank you for the great video BTW! :-)

[@TheRepairer]

I’d remove it to do the job then refit. it’s just a strut brace which helps prevent chassis flex when the vehicle is in motion, cornering etc.

[@alarynxforditoiroda4785]

Thanks a lot! I will do so! I'll do it next weekend (need to order some compatible good quality premixed coolant). I'll keep you updated! Anyway, excellent guide, thank you so much!!!!

[@paulmcconnell7445]

@@TheRepairer Good to know. No way I can get at those pipes with it in situ either!

[@ukgardener973]

Thanks.