Heater issues citroen synergie/evasion

[DJSteve]

Ok had a check of all the various coolant hoses today. The pipes to and from the webasto are hot (webasto was not running today). Radiator top hose hot. And one pipe (the right hand one) going i to cab hot but the return feels lukewarm if that. Does that indicate a blocked heater matrix? And if so whats the best way to unblock it or is it a replace job

[GiveMeABreak]

Hi Steve - sorry about the delay in getting back - this one slipped through with everything going on.

Here are the diagrams of your Evasion - you'll need to click on them to zoom them up:

If you look at number 7 on the above diagram - that is the A/C reduction gear. If the gearing on that has worn, it may well be keeping the airflow at the last position if was set to, so could be restricting the amount of hot air into the cabin. The part number is 6447 K7 and seems to still be available from Citroen at £175.40 inc. in case you think it is this causing the problem and can't get a second hand spare.

The above is the car heater and the hoses, so you can see where they all are.

Lastly, the diagram below shows the additional heating installed on your vehicle:

[DJSteve]

Hi Steve - sorry about the delay in getting back - this one slipped through with everything going on.

Here are the diagrams of your Evasion - you'll need to click on them to zoom them up:

Evasion Heater Detail.PNG
If you look at number 7 on the above diagram - that is the A/C reduction gear. If the gearing on that has worn, it may well be keeping the airflow at the last position if was set to, so could be restricting the amount of hot air into the cabin. The part number is 6447 K7 and seems to still be available from Citroen at £175.40 inc. in case you think it is this causing the problem and can't get a second hand spare.

Evasion Water Heater.PNG
The above is the car heater and the hoses, so you can see where they all are.

Lastly, the diagram below shows the additional heating installed on your vehicle:
Evasion Water Reheater.PNG

Thanks very much for this. Ill have a better look once i do get home. Dont auppose you happen to know how much of a chore the heater matrix is to replace assuming i cant flush it and try and unblock it

[ken newbold]

They're really not a bad job to replace, I have a couple of spare used ones here if you need one. I filled them with antifreeze/water when I removed them. A new one wouldn't be too expensive though.

[DJSteve]

They're really not a bad job to replace, I have a couple of spare used ones here if you need one. I filled them with antifreeze/water when I removed them. A new one wouldn't be too expensive though.

How much would you be wanting for one just incase

[ken newbold]

A fiver + post

[kenbw2]

Cheers for the tips on checking hoses. I suspect mine's blocked too from an oil cooler leak a few months ago. I'll give mine a check, but I suspect I'm about to follow the same procedure as you.

[white exec]

In addition to replacing the heater unit, if you need to clean out engine oil that has contaminated the cooling system (from a leaky oil cooler), I can recommend Liqui Moly Radiator Cleaner ref.2506 300ml. Add to the cooling system, following the instructions. Removes oil, grease, calc etc., very efficient, and harmless to mixed metals. Available anywhere that sells Liqui Moly products.

It might be able to unblock a heater matrix bunged up with oil and calc. Worth a try before replacing the heater matrix.

[DJSteve]

ok got an update for everyone today,

got some time and decent weather to try and get the heater matrix flushed, once i eventually got the two pipes pulled off that is, i have discovered i need to do a full cooling system flush at some point as the coolant is a loverly rusty brown color. but thats for a future job, flushed through the matrix until water was fairly clear coming out and reassembled the pipework(still not sure i have those back on properly but not leaking so ok for now)

bled the system out as i did lose a bit of coolant and water level is stable as far as i can see.

i now do have some heat (still not massively hot but more just warm air) but only if i put a/c and recirc on. otherwise the temp is a lot lower but still warmer than i was before.

so looks like i will be looking at the heater mix motor next.

[white exec]

One step forward: good news. Do use that LiquiMoly stuff for the flush. Best to buy two.
Is thermostat ok? Heater matrix feed should be really hot, and feed to radiator cold, before thermostat opens, if the 'stat is working. If both matrix and main rad warm up from cold at the same rate, then the 'stat is duff/stuck open/missing.

[DJSteve]

nope i just used water for this round as its all i had to hand. the stat is fine, and feed pipework seems ok, (though i havent checked the output of the matrix since flush due to lack of light) car takes the average time for a deisel to warm up(5miles or so) it actually warms up faster than my vauxhall insignia does haha

[kenbw2]

got some decent weather

Where did you find that?!

to try and get the heater matrix flushed, once i eventually got the two pipes pulled off that is, i have discovered i need to do a full cooling system flush at some point as the coolant is a loverly rusty brown color. but thats for a future job, flushed through the matrix until water was fairly clear coming out and reassembled the pipework(still not sure i have those back on properly but not leaking so ok for now)

bled the system out as i did lose a bit of coolant and water level is stable as far as i can see.

How much coolant did you lose? I assume whatever you lost came out onto the floor.

Which pipes did you disconnect - the ones at the back of the engine bay, or the ones between the two footwells?

[DJSteve]

got some decent weather

Where did you find that?!

to try and get the heater matrix flushed, once i eventually got the two pipes pulled off that is, i have discovered i need to do a full cooling system flush at some point as the coolant is a loverly rusty brown color. but thats for a future job, flushed through the matrix until water was fairly clear coming out and reassembled the pipework(still not sure i have those back on properly but not leaking so ok for now)

bled the system out as i did lose a bit of coolant and water level is stable as far as i can see.

How much coolant did you lose? I assume whatever you lost came out onto the floor.

Which pipes did you disconnect - the ones at the back of the engine bay, or the ones between the two footwells?

Two at top rear of engine bay behind where air filter goes. Did not loose a massive amount coolant though didnt look like their was much antifreeze in the system either so i need to do a proper flush and refill at some point.