Heater matrix pipes - one cool, one warm. Must be blocked?

yoda960 · Nov 22nd, 2017, 16:58

Hi Chaps

I posted a thread regarding re-calibrating my heating (I am getting no hot air at all). Some great suggestions on there led me to check the flow/return pipes to the heater matrix.

One pipe is nice and warm, the other is cool. Shouldn't both be hot? Engine was hot when I checked them.

Anyway, how common is a blocked heater matrix? I guess it has to be this.

My coolant is fresh Volvo, changed it only a few months ago. The coolant in there didn't have loads of crud in etc, so i'm a bit peeved that the matrix is blocked (if that's the issue!)

It has been suggested to me to disconnect the pipes and flush through with a pressure washer. Anyone done this before? Are the pipes easy to disconnect from the block/accessible?

Any suggestions welcome, really want to avoid taking the dash out to change the matrix! Sounds like a mare!

Thanks in advance chaps.

Matthews 855 T5 · Nov 22nd, 2017, 17:26

Hi Yoda

https://www.youtube.com/watch?v=02AkPvT1bVg

Roberts done a very good diy version.

Matt

yoda960 · Nov 22nd, 2017, 22:15

Thanks for that, very useful if it needs pulling and replacing!

Anyone had an issue with it getting blocked though? It's deffo no leaking as my coolant level has been bang on, and i've done a good 3k miles on it since changing the coolant...

NI_Volvo_Nut · Nov 23rd, 2017, 13:06

Possible airlock?

Although how cool is it? I would expect one to be cooler as the matrix is effectively a radiator. Be very unusual for a matrix to be fully blocked I would have thought.

yoda960 · Nov 23rd, 2017, 13:38

Very cool. I don't think it can be an airlock, it's been drained and filled several times with many miles in between, I was flushing old coolant out. I filled with fresh Volvo. Never improved once during this, so that would have to be one stubborn airlock!

ASt85 · Nov 23rd, 2017, 14:35

You could try a back flush from the connection point of the lower & upper heater matrix hoses to the rest of the system in the engine bay - it depends upon how your hoses are connected under the bonnet rather than at the back of the matrix as it's a PITA to disconnect both heater hose clamps/unions in the cab under the dash and then connect hoses to flush it in situ.

Tomoose · Nov 23rd, 2017, 18:24

Quote:

Originally Posted by Matthews 855 T5

Hi Yoda

https://www.youtube.com/watch?v=02AkPvT1bVg

Roberts done a very good diy version.

Matt

Be careful, its a very different job on RHD cars.

yoda960 · Nov 24th, 2017, 19:43

Oh dear, so that vid is useless for us Brits? I'll attempt flushing the matrix this weekend if the weather is dry....

Brendan W · Nov 24th, 2017, 20:24

At the risk of stating the bleeding obvious make sure you back flush.

yoda960 · Nov 24th, 2017, 20:29

Was going to flush both ways, but back flushing first is certainly best in case some debris has blocked it, saves pushing it in even further!

Anyone know which pipe is which when looking in the engine bay?

looking from the front of the car towards the bulkhead, I think it was the right hand pipe that was warm, the left hand pipe was cool/cold. So I guess I should try and force water through the left hand pipe? Would that be right?

Thanks chaps

Nov 22nd, 2017, 16:58	#1
yoda960 Volvo 960 Last Online: Today 23:10 Join Date: Mar 2008 Location: Planet Earth	Heater matrix pipes - one cool, one warm. Must be blocked? Hi Chaps I posted a thread regarding re-calibrating my heating (I am getting no hot air at all). Some great suggestions on there led me to check the flow/return pipes to the heater matrix. One pipe is nice and warm, the other is cool. Shouldn't both be hot? Engine was hot when I checked them. Anyway, how common is a blocked heater matrix? I guess it has to be this. My coolant is fresh Volvo, changed it only a few months ago. The coolant in there didn't have loads of crud in etc, so i'm a bit peeved that the matrix is blocked (if that's the issue!) It has been suggested to me to disconnect the pipes and flush through with a pressure washer. Anyone done this before? Are the pipes easy to disconnect from the block/accessible? Any suggestions welcome, really want to avoid taking the dash out to change the matrix! Sounds like a mare! Thanks in advance chaps.

Nov 22nd, 2017, 17:26	#2
Matthews 855 T5 Master Member Last Online: Apr 16th, 2024 13:36 Join Date: Dec 2006 Location: York	Hi Yoda https://www.youtube.com/watch?v=02AkPvT1bVg Roberts done a very good diy version. Matt __________________ Get that kettle on!

Nov 23rd, 2017, 13:06	#4
NI_Volvo_Nut Volvologist Last Online: Dec 6th, 2023 11:13 Join Date: Aug 2008 Location: Bangor - Norn Iron View Photos By: NI_Volvo_Nut	Possible airlock? Although how cool is it? I would expect one to be cooler as the matrix is effectively a radiator. Be very unusual for a matrix to be fully blocked I would have thought. __________________ What's the matter with the car I'm driving? Can't you tell that it's out of style? Should I get a set of white wall tires? Are you gonna cruise the miracle mile?

Nov 23rd, 2017, 14:35	#6
ASt85 Premier Member Last Online: Apr 16th, 2024 14:11 Join Date: Aug 2010 Location: Walderslade....Kent	You could try a back flush from the connection point of the lower & upper heater matrix hoses to the rest of the system in the engine bay - it depends upon how your hoses are connected under the bonnet rather than at the back of the matrix as it's a PITA to disconnect both heater hose clamps/unions in the cab under the dash and then connect hoses to flush it in situ. __________________ The saddest moment is when the one who gave you the best memories....becomes a MEMORY V70 SE 2004 2.3L T5 Geartronic, C70 2005 2.0T Automatic, Sold 2.4l 20 Valve Automatic Torslander Sold 854 GLT 20v Auto

Nov 22nd, 2017, 22:15	#3
yoda960 Volvo 960 Last Online: Today 23:10 Join Date: Mar 2008 Location: Planet Earth	Thanks for that, very useful if it needs pulling and replacing! Anyone had an issue with it getting blocked though? It's deffo no leaking as my coolant level has been bang on, and i've done a good 3k miles on it since changing the coolant...

Nov 23rd, 2017, 13:38	#5
yoda960 Volvo 960 Last Online: Today 23:10 Join Date: Mar 2008 Location: Planet Earth	Very cool. I don't think it can be an airlock, it's been drained and filled several times with many miles in between, I was flushing old coolant out. I filled with fresh Volvo. Never improved once during this, so that would have to be one stubborn airlock!

Nov 24th, 2017, 19:43	#8
yoda960 Volvo 960 Last Online: Today 23:10 Join Date: Mar 2008 Location: Planet Earth	Oh dear, so that vid is useless for us Brits? I'll attempt flushing the matrix this weekend if the weather is dry....

Nov 24th, 2017, 20:24	#9
Brendan W Premier Member Last Online: Apr 2nd, 2024 19:50 Join Date: Dec 2007 Location: Wexford	At the risk of stating the bleeding obvious make sure you back flush.

Nov 24th, 2017, 20:29	#10
yoda960 Volvo 960 Last Online: Today 23:10 Join Date: Mar 2008 Location: Planet Earth	Was going to flush both ways, but back flushing first is certainly best in case some debris has blocked it, saves pushing it in even further! Anyone know which pipe is which when looking in the engine bay? looking from the front of the car towards the bulkhead, I think it was the right hand pipe that was warm, the left hand pipe was cool/cold. So I guess I should try and force water through the left hand pipe? Would that be right? Thanks chaps

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