Heaters blowing luke warm.

[Lummox]

Afternoon all,

I have noticed that the heaters in the car are only blowing luke warm at best. I have checked all the obvious head gasket tell tails and there are no other symptoms (Oil still at correct level and no trace of water, no evidence of exhaust gas in the expansion tank, the car does use water but approx one cup full every 2 months)
Any ideas on where i should go next? I was thinking water pump or solenoids for the heater controls, just wondering if anyone has suffered this problem before.

Lummox

[X5Sport]

Thermostat allowing the temp gauge to get halfway?

Upper vent control temp wheel set to middle (white bar)?

Climate control has 'Auto' selected?

Just thinking of all the obvious things are set correctly 'just in case'.

Richard

[Smeeagain]

hows luke now ? is he  still being blown warm by the heater

Smee

[Lummox]

Thanks for the replies (even you smee as you made me laugh) I have made some progress as I now have hot air to the paasenger side but luke is still in the drivers side. I "tapped" the solenoids under the bonnet that control the hot water flow to the heater matrix. I have spoken to my local indy and he has confirmed that they can get stuck and it is a common fault on audis as people leave themturned down over the summer and then come this time of year  they have seized up due to lack of use and anti freeze going crusty on them. He reckons he can take it to bits and clean it up but he reckons it is only a 50/50 chance of getting them working again. Looks like a trip to the dealers for a new one.

Cheers

Lummox

[jaynana]

[quote="Lummox"]
Thanks for the replies (even you smee as you made me laugh) I have made some progress as I now have hot air to the paasenger side but luke is still in the drivers side. I "tapped" the solenoids under the bonnet that control the hot water flow to the heater matrix. I have spoken to my local indy and he has confirmed that they can get stuck and it is a common fault on audis as people leave themturned down over the summer and then come this time of year  they have seized up due to lack of use and anti freeze going crusty on them. He reckons he can take it to bits and clean it up but he reckons it is only a 50/50 chance of getting them working again. Looks like a trip to the dealers for a new one.

Cheers

Lummox
[/quote]

if one side works and you suspect the heater matrix, either side should have a thermostat somewhere in the heater matrix, plus this is the valve that controls the coolant flow to left/right:

item 16:




we've heard of a couple of variants on this, this is as per my car..

hth..

[Lummox]

Thanks for the post Jaynana. I replaced those a couple of days ago (155 quid later) but they didn't cure the problem. I have since found out that item number 9 on the diagram is an "additional water pump" and it is that that is not working. The additional water pump supplies hot water to the heater matrix without the engine running. I have just ordered one from bm at 120 quid and will be fitting it on monday so I will update you then

Thanks again to everyone for your contribution

Lummox

[jaynana]

Item 9 is a circulation pump and that's what makes the coolant do it's rounds when the webasto aux heater is enabled in pre-heating (ie without engine running) mode.

I didn't realise that it had a job to do in normal operations (ie with engine on - is t there a mechanical pump?). I could well be wrong. Btw u can hot wire it to see if it works.

[Lummox]

Jaynana, my car doesn't have the Webasto heater so the pumps sole purpose in life is to circulate the coolant through the heater matrix (it still keeps running when the engine is running). When i put a screwdriver onto the pump and put my ear to it i can here a horrible buzzing/screeching sound so it is trying to turn, I then belt it with a hammer and the noise changes to what i suppose you would say an electric water pump should should sound like and i get heat in the car so it looks to me like the bearings in the pump have gone or it is gunked up. I have ordered a new pump and will fit it when i get it and let you know back.
The best way to hear it is make sure the car is warmed up to normal temperature and with the engine switched but the ignition system on - turn both sides of the heaters up to 32 and you will hear a faint buzzing sound, now turn both heaters down to 16 and you should hear the buzzing stop.

Cheers

Lummox

[jaynana]

sounds like you're on the right path  :thumbup:

[Lummox]

Well now that the additional water pump is fitted all is well, Luke is now longer being blown warm he is getting the full wrath of satans sister!!!! I didn't realise heaters could be so hot in a car, very impressed with the difference. The pump and or water valve must have been on their way out since i got the car as the heaters have never given the heat that they are providing now!!!!!

Thanks again for the input

Lummox