Replacing Heater Matrix

[SiC]

Has anybody replaced their heater matrix in a mk3?

Is it a complete dash out job or did Ford show some genius and make it less of a ball ache?

I suspect my matrix is partially blocked causing a restriction in the collant system leading to a failed head gasket.

[Chrispb]

The matrix and the evaporator can both be removed from the right hand side without removal of the heater unit but does involve cutting off the coolant pipes so will not be reusable.
A new matrix/evaporator comes with removable pipes.

What is the condition of the coolant? is it clear with anti freeze/coolant or a rusty sludgy mess?

Has it been overheating and loosing coolant/water regularly

What CC engine is this?

[SiC]

Hi Chris,

I bought the car second hand in June. Its a 1.8TDCI. Within a month the head gasket failed.

It was sorted by a engine specialist and having parted with a grand of cash on all the works involved (plus new thermostat, water pump) i got it back with a 12,000 mile warrantly. 

I noticed the heaters in the cabin never blow as hot as expected on HIGH and not long ago the headgasket failed again.

Thankfully this time it didnt cost a penny and was fixed under warranty.

Both times the HG has failed it had blown all coolant out of the system and didnt indicate an overheat on the temp guage.

I couldn't comment on what state the coolant was in previously (prior to the first hg failure) but its now all new coolant.

The engine specialist back washed the matrix and said some crap came out, and he also mentioned it still wadnt blowing as hot as it should so reckoned the matrix had a restriction in it and was a cause of the HG failure.

Im wondering if the previous owner either didn't change their coolant as often as they should or if they had a leak in the matrix and may have used radweld or something similar and maybe that's caused the partial blockage.

So from what your saying a new mattix wouod come with removable pipes that will replace the ones id have to cut out to free the matrix?

Thanks

[Chrispb]

After all the series of events it's quite possible that crap has got lodged in the matrix but that would not have caused head gasket failure.
Coolant loss and boiling over loosens any corrosion and particles then dumping it where there is restricted flow.
Have you tried draining the system and adding a system flush, this is suppose break down scale then reverse flush following  the guide on the product.
I would certainly try this before going down the new matrix route.

[SiC]

I believe the engine specialist did use an automotive detergent of some kind when back flushing the matrix.

Couldn't hurt to do it again I guess...but the heater is luke warm at best on HIGH when the engine is up to temp.

[Chrispb]

Of course there may be a problem with the air flaps in the heater not moving to the full heat position, there is no water valve in the circuit to reduce the flow.

[SiC]

Thanks for the info Chris. Is there a means of confirming the air flaps via a diagnostic feature on the heater unit?

[insanitybeard]

Is there a possibility that whoever replaced the head gasket twisted/crimped or incorrectly refitted a coolant hose causing a restricted coolant flow to the heater matrix? As the head would have had to come off to replace the gasket a few coolant hoses would have been disturbed too.

[SiC]

It's certainly worth me investigating InsanityBeard.

Not sure if I've misunderstood another conversation elsewhere, but is there some sort of heat exchanger unit on the exhaust side that involves the coolant/exhaust gases?

If so, if such a unit was not working as intended could it cause a restriction in the coolant flow?

[insanitybeard]

Sounds like you're describing the EGR cooler, basically it's a water jacket/heat exhanger which uses the engine coolant to cool the hot exhaust gas before it is recirculated back into the inlet manifold via the EGR valve. How it is 'plumbed in' to the coolant system probably varies from vehicle to vehicle so I'm not sure how much of a restriction having a blocked EGR cooler would cause, though it's likely to be a branch off of one of the main coolant pipes, not a main coolant passageway itself.

[SiC]

Thanks for the info, that sounds like the one.

[SiC]

I finally got around to getting the car up to temp and checking the coolant hoses on the matrix near the bulkhead.

1 hose (leftmost hose as you look at it - highlighted in red) was hot enough to be uncomfortable to hold. The 2nd hose (rightmost highlighted in blue that drops down the back of the engine) was just warm and I could have held it all day. So, I guess a blockage in the matrix is the problem with the heater 

I also noticed something else I was hoping someone could help me with, there is what appears to be a breather pipe of some sort on the top-rearside of the engine. I noticed it was kinked badly and when I looked in to it further I realised it was only attached at one end!

From the attached pictures referencing the breather pipe, can anyone tell me what it is and where it should go as I couldn't see anywhere (I didn't get under the car as it was on the street).

[insanitybeard]

It's really difficult to be sure where that should be going without being able to look at that general area of your engine bay to check the other hoses as well and try to trace them all back, but certainly that hose should not be kinked and disconnected like that. I have worked on the Lynx diesel engine your Galaxy has fitted but not on the incarnation of it fitted to the Mk3 Galaxy, it may be a breather hose but they usually come out of the top of the rocker cover.

Due to the location of the disconnected hose I am almost wondering if it may actually be a coolant hose going to the EGR cooler which somebody has bypassed and effectively disconnected, the question is, if they have done this, what have they blanked off or rerouted to prevent a coolant leak elsewhere.....?

It may have a bearing on your heater problem if your coolant hoses have been messed around with and not routed correctly, because the coolant flow in the circuit will have been altered. Like I say, the thing that makes me think it could be a disconnected coolant hose is the fact that it is in the area I think the EGR cooler is situated (to the rear of the engine block underneath the EGR valve), and there aren't usually any breather hoses in that area.

Somebody with more knowledge of the setup on the Mk3 Galaxy may be able to prove me wrong with my reasoning, but something is definitely not right there- the last of your 3 images shows a metal mounting bracket near to that pipe connection which I think may be a mounting for the EGR cooler, like you can see in diagram 20c (bottom right) here, this cluster of diagrams shows some of the breather hoses as well (top left diagram), you can click on each individual diagram to enlarge it.

My hunch is that in the course of taking the head off to replace the head gasket, whoever worked on your car has either forgotten where the various hoses went and either refitted them incorrectly or deliberately bypassed something.

[SiC]

Thanks for the info InsanityBeard.

Having looked at the diagram I have an idea what i should be  looking for and will have a better look at it over Christmas.