No Heat 2.5td Estate, Blows cold air - heater matrix is hot

[XM_on_ a_ shoestring]

What a time to pack up! I've bled the system the heater matrix is hot. I think it's something to do with the flaps as no air is blowing into footwells, it's just coming out of top, ie screen and dash. It's a vsx 2.5 td exec estate, all electric buttons and facia, no dials. How do I remove the glovebox without breaking the locking mechanism? All the screws are loose, there's nothing in the Haynes manual to explain this. It seems the lock mechanism is preventing it from coming out.
Great forum lots of helpful advice, I hope I'll able to help someone with what I've learnt over the past 10 years.

[noz]

Hi shoestring,

From your handle I conclude that you're a born optimist . Welcome to club-xm. You'll find a like-iminded bunch of nutters here who for inexplicable reasons drive and maintain XM's. Club-XM survives and proliferates by the common sharing of information on how to keep the darlings running. I'm sure in time you'll be able to impart your own hard earned information for the benefit of others sanity.

The last and elusive screw holding your glovebox down is hidden behind the plastic fascia around the lock. It prises out by using a small screwdriver as it just clips into position. There's a torx screw just like the rest just to the side of the lock.

However, if the matrix is hot and you are getting hot air to the windscreen and face vents then you're at the wrong end of the heater box for the fault. The flap motor at the nearside/glovebox side (RHD) is for controlling the bypass around the heater matrix. The more bypass the colder, the less bypass the warmer the air. In contrast, the directional flaps are all driven from the mechanism on the offside (steering wheel side) (RHD) of the heater box. On my 2.5 the directional flaps are manually controlled via a dial on the dash linked to the flap with a cable. From your description it sounds like you have a higher trim level and the mechanism may be driven by a servo motor with a signal coming from some heater control computer on the dash. I've attached a photo of the end of the heater box. The circular plastic gear can be driven with a cable or a servo motor. The heater box design is the same for all models. Only the level of automated control varies with trim level. The large rectangular hole is where the heater matrix lives.

You should be able to access the motor and geared drive by removing the carpeted panel on the side of the central console. Until you do this first level of checking I can't advise any further on the possible faults. However, you could try taking the servo motor off (remembering the motor position and the flap position for reassembly). Turn the gear so that the air is directed towards the floor. This will prove the flap mechanism is OK and the problem lies with the drive.

Let us know how you get on.

cheers

noz

[noz]

Sorry wrong photo

[XM_on_ a_ shoestring]

Hi Noz
Thanks for the quick reply. I've been outside most of today freezing my spheres off, sorting out this no heat problem!
The servo's all work, I watched them all moving. I warmed up the engine, felt the heater matrix pipes and the top one actually felt noticeably cooler. Air lock again I thought. On 2.5td the bleed screw is right behind rocker cover. It did have air in again. I bled it, then when I was topping up coolant in tank, I noticed what appeared to look like slivers of lime scale (like you get in a kettle) but worse. I took header tank off and shook out all this c**p. It was actually pieces of a thin grey looking plastic with red dye(radweld maybe) all over it. It looks like these were baffle plates in the header tank once upon a time. I'll post a picture of what fell out of the tank!! Incidentally the temperature guage registers at 95C most of the time and reaches 100C when under load. So. what I think is causing the problem now is this plastic that has disintigrated in the header tank has distributed itself around the cooling system and some bits have lodged in the heater matrix area. So, tomorrow I'm going to reverse flush the system out with a hose pipe then try again. I may have to disconect the heater matrix pipes to flush the heater matrix out properly, it's going to be a long haul.
Once again thanks for the info, at least I know how to remove the glovebox now

[xmexclusive]

Hi shoestring

The running temperatures you quote look high to me. I have run some 2.5's for a few years now and the normal running temperature all of my cars is 90 with increase to 92 under load. The sort of temperatures you quote are only usually reached when towing heavy loads up steep grades. The engine is not designed to stand high temperatures for long periods. It is important to use an extension on the header tank when trying to clear air locks on a 2.5, I use a 2ltr lemonade bottle with the bottom cut off, the threads for the cap filed off so with an o ring it fits with a water tight seal in place of the header tank cap. I think Haynes tells you how to rev the engine to clear the air.

Sorry not to be able to give any more useful information, I just thought that it would be helpful to know the normal temperature.

Regards

XMexc

[XM_on_ a_ shoestring]

Hi XMexc
Thanks for the idea for getting airlock out of system. I'll have a go when I get chance(could be over Xmas hols or earlier if it keeps on being so cold!).
I'm putting a picture on to show the contents of the header tank - the baffles were totally disintigrated! I'm assuming some of this debris has collected in the heater pipes.
But I'll try bleeding it like you suggested first, that sounds an easier option.