Heater still not working right !

[Bullnose75]

So guys,heater in my V6 Tourer has never produced as much heat at the vent outlets as it should. So far i've replaced slightly clogged heater matrix with a brand new one and replaced the completely clogged engine oil cooler with a brand new one also. Carefully refilled cooling system so no air locks. But even after doing that the heat coming from any/all of the vents is pretty rubbish ! Didn't bother me much in milder weather but could now do with it working properly with winter approaching.

Is there a door in the heater box somewhere that might not be opening fully hence why amount of heat coming from vents is so poor ?

I've just had another check of heater pipes going in and out of heater matrix and with engine idling with coolant temp between 95 and 99 degrees both in and out pipes of heater matrix are too hot to hold so I know the flow of water through the heater matrix is ok as is the temperature of the coolant in it.

So why don't I get much heat coming out of vents ?
Is there a solenoid or switch or something that might be faulty/not working that is stopping a full flow of air passing through heater matrix when you need it ? Paul

[roverbarmy]

Have you turned the thumbwheel under the clock, to stop it drawing too much air from outside? (fresh air bypass)
https://rimmerbros.com/Item--i-JBE100060LNF

[Bullnose75]

Originally Posted by roverbarmy

Have you turned the thumbwheel under the clock, to stop it drawing too much air from outside?
https://rimmerbros.com/Item--i-JBE100060LNF

Have tried that but that only controls how much cool air from outside comes through the dash vents doesn't it ? Didn't make any difference anyway mate

[Bullnose75]

Car gets warm enough to drive eventually but on frosty mornings takes ages to clear front windscreen. Even with all air directed at screen with coolant temp at 99 degrees air coming out of vents at bottom of screen is still barely warm both in economy setting and with air con turned on

[roverbarmy]

Have you done the diagnostics check?
https://www.the75andztclub.co.uk/for...hread.php?t=46

[T-Cut]

If you direct the 'heating' to the footwells and run it, do you feel an obvious air flow coming from the ducts either side of the central console? The flow should vary as you change the fan speed. The same principle applies to the windscreen ducts. The heating system works by mixing hot air from the heater matrix with cold (and possibly chilled) air from outside. The hot water flow through the matrix is not controlled, it's full bore all the time the engine's running and as it's hot as the coolant circulating from the head. So, the system uses flaps to open and cover various ducts to mix and deliver warmed air to the desired locations. If you can feel the air flow but not the heat, then the flaps allowing hot air from the matrix aren't working properly.

Accessing the heater control flaps involved in all this is quite a big job as I understand it. The heater consul/dash have to be removed. Check what Haynes says.

TC

[Bullnose75]

Originally Posted by roverbarmy

Have you done the diagnostics check?
https://www.the75andztclub.co.uk/for...hread.php?t=46

Will do the diagnostics check later

[Bullnose75]

Originally Posted by T-Cut

If you direct the 'heating' to the footwells and run it, do you feel an obvious air flow coming from the ducts either side of the central console? The flow should vary as you change the fan speed. The same principle applies to the windscreen ducts. The heating system works by mixing hot air from the heater matrix with cold (and possibly chilled) air from outside. The hot water flow through the matrix is not controlled, it's full bore all the time the engine's running and as it's hot as the coolant circulating from the head. So, the system uses flaps to open and cover various ducts to mix and deliver warmed air to the desired locations. If you can feel the air flow but not the heat, then the flaps allowing hot air from the matrix aren't working properly.

Accessing the heater control flaps involved in all this is quite a big job as I understand it. The heater consul/dash have to be removed. Check what Haynes says.

TC

Yep,air flows from all the ducts at whichever speed you select just not at the temp you select.
And yes,as hot coolant always flows through the heater matrix as mine is that's what made me suspect a door or flap wasn't opening when it should,not opening enough anyway

[Bullnose75]

Originally Posted by Bullnose75

Will do the diagnostics check later

Right,just did the diagnostics test - first time only fault codes that came up were 21 and 22 re sunlight sensors but it is quite shady where car is at mo.Tried again with torch pointing at sunlight sensor and only fault code 22 came up that time.
Guess no faults then really hey

[trikey]

Any change in temp when you apply 2500 rpm for a few mins?