Heater problems - help please :)

[madpugger]

Guys, as most you know, I bought Neils Black S2 Avant which I am using as a runaround right now as my white one has no engine in it

Anyway, this thing has Aircon (not climate) which my white one doesn't so I know little about it. There is NO hot air coming out the vents (which is rather pleasant in the snow!). When I turn the knob from cold to hot, it turns freely but it seems like the air flow is restricted slightly (maybe 20-25% reduction) but there is no hot air. I have checked the coolant bleed at the matrix pipe (is this supposed to be on the RHS of the two (which would be the left as you look from the front of the car)? Anyway, when the engine is running there is a little water comes out the bleeder, not a huge amount. The coolant fan comes on and off as expected, although the gauge in the dash doesn't show very warm ever. I have a new MFTS on its way. Strangely the hose from the thermostat was cold but the Rad was hot to start with (aux rad has been removed).

Does anyone have any ideas? Is there maybe an electrically controlled valve for the matrix in air con cars?

Help welcomed

Mike

[urS6Tom]

Guys, as most you know, I bought Neils Black S2 Avant which I am using as a runaround right now as my white one has no engine in it

Anyway, this thing has Aircon (not climate) which my white one doesn't so I know little about it. There is NO hot air coming out the vents (which is rather pleasant in the snow!). When I turn the knob from cold to hot, it turns freely but it seems like the air flow is restricted slightly (maybe 20-25% reduction) but there is no hot air. I have checked the coolant bleed at the matrix pipe (is this supposed to be on the RHS of the two (which would be the left as you look from the front of the car)? Anyway, when the engine is running there is a little water comes out the bleeder, not a huge amount. The coolant fan comes on and off as expected, although the gauge in the dash doesn't show very warm ever. I have a new MFTS on its way. Strangely the hose from the thermostat was cold but the Rad was hot to start with (aux rad has been removed).

Does anyone have any ideas? Is there maybe an electrically controlled valve for the matrix in air con cars?

Help welcomed

Mike

I'm going to be following this thread as I have exactly the same problem in the S6!

[madpugger]

I'm going to be following this thread as I have exactly the same problem in the S6!

I have an S4 with the same problem, but in it I think the head gasket is gone...

[rj scotty]

I would have said this is a matrix issue. Take the hoses off and run a hose pipe through
hopefully it will flow nicely.
I have also had an air lock in the matrix cause this so now I always fill the matrix up first when replacing coolant.

Cheers

Rich

[s2_wot]

Having the same problems on the S6, cannot get the air out of the matrix. Now in my case I'm sure the water pump is leaking a couple of drops. Maybe the head gasket is gone too, I honestly don't think so. It's driving very well etc.

[rj scotty]

If you rev the car (a little!) from could you can hear the bubbles in the matrix if you have the problem I had.
The way I cured it as I said was to fill the matrix up with a hose pipe and as water was p**sing out quickly slip the hoses back on.

Are you reading a normal temperature on the engine gauge?

Mine is very low when on the motor way at the moment but I do still have heat think a thermostat replacement is coming

[s2_wot]

If you rev the car (a little!) from could you can hear the bubbles in the matrix if you have the problem I had.
The way I cured it as I said was to fill the matrix up with a hose pipe and as water was p**sing out quickly slip the hoses back on.

Are you reading a normal temperature on the engine gauge?

Mine is very low when on the motor way at the moment but I do still have heat think a thermostat replacement is coming

I'll give that a go this weekend. Could be a good fix. I've a new thermostat fitted and the display sits at 87 degrees all the time once warmed up. Just no heat in the matrix.

[iain1067]

You need to bleed the system, on the urs4/6 there is a bleed screw in one of the hoses that goes through the bulkhead, if you look under the cover where the wipers are passenger side you will find it.

[rj scotty]

If it's a big air lock the bleed screw ain't enough BTDT

[blackrat]

Interesting!!!
I have just changed the thermostat on my s4 and refilled the coolant.
Went to bleed it under the scuttle tray on the exit hose from the matrix and guess what, no bleed screw (s6 has one!!).
Spent 45 mins getting some air out of the matrix by slipping the hose off slightly, revving to 3000 etc and just enough to get air bubbles.
This has made a slight difference but there is obviously a lot of air in there as my cabin air is luke warm.
I think as suggested, the only way to bleed properly is to stick a hose in the matrix.
Thats tomorrows job

[newsh]

Another way is to find a length of tube that fits tightly into the header tank and projects upwards a foot or so, fill this with coolant so you've got a bit of "head" and then open the bleed screw

[rj scotty]

Nice advice that.I'll give that a go next time

[johne]

Another way is to find a length of tube that fits tightly into the header tank and projects upwards a foot or so, fill this with coolant so you've got a bit of "head" and then open the bleed screw

If you can't find a suitable length of hose you can achieve the same effect by blowing into the header tank.

John

[madpugger]

Well had some success this morning...

I borrowed my dad's pressure test kit yesterday to check the S4's head gasket which came in pretty handy.

I took the matrix hoses off and fitted an old OE one with a hose attached to it and ran a load of hot water through it. I then put the fan on and had some hotish air which is good, it means that the inside bits all work fine! So i reattached the hoses to the matrix and fitted the pressure test kit to the header tank, pumped up the bladder to seal it, then pressured the system up to a few psi. I then opened the bleed screw on the matrix pipe and after getting soaked by the jet of water checked the rad bleed too. Fired up the car with the cap back on and let warm up. It has hot air! The only problem is it doesn't stay too warm at idle, it needs revved a bit to come warm, so I think the water pump could be on the way out, it sounds noisy...

Will see how it goes though. Strangely the temp never goes that high on it even on idle at a standstill, although the coolant fan comes on and off, probably a duff MFTS so will swap when it arrives from QC.

[blackrat]

Right....I have now cured my problem.
Basically I have changed the coolant and thermostat and when refilled the heater would not get warm.
Found out that hot water was going to the heater matrix but no outlet, it used to get warm so I knew it was not blocked.
There is no bleed valve on the s4 which I have.
So....as suggested I attached an old rad hose onto the header tank and filled the tank up.
Car was reversed onto ramps which put the heater matrix at the highest point of the coolant system, to allow any air to come out at this point.
Carefully slid the hose back off the matrix to a point when air bubbles would come out.
Occasionaly revved engine, squeezed the top heater hose and eventually 1 hour later the matrix was air free and the heater is now hot.
Cushty.
Right, now onto the next problem