[defenderman]

Hi everyone, My wife's Rover 25 heater is only blowing cold air, this suddenly happened, one minute blowing hot air & the next just cold air. I've checked the heater matrix pipes when the engine has reached normal running temperature, both the inlet & outlet pipes to & from the heater matrix are cold to the touch.
The question is, could this be due to a thermostat and/or a water pump failure, there has been no coolant loss & the the temperature gauge never rises above the mid position on the dial even when the radiator fan kicks in. The vehicle drives the same as it's always done & there is no power loss.
A mechanic tested for HGF using the chemical method via the header tank with no change in the liquid indicating all is well with the HG. There are no traces of any contamination in the coolant liquid, no discolouration of the engine oil or traces of water/oil mixing.
Any suggestions would be more than welcome to resolve this issue as our frustrations are building.
Thanks in anticipation.

[Vinny1979]

Have the cambelt / water pump been changed to your knowledge?

What about the thermostat?

Vinny

With the car now at say 14 years old I would imagine its due its 2nd change of belt (6years 1st lets say) so would do water pump aswell, whilst at it thermostat too and a flush

[defenderman]

Hi Vinney, The cam belt was changed three years ago, neither the water pump or thermostat have been touched since we purchased the vehicle five years ago?

[defenderman]

Hi Vinny, thanks for the advice, I've just been in touch with Rimmers & they are sending me a water pump kit comprising of a new water pump, cam belt & tensioner plus a new thermostat & sealing rings etc. Just have to get it fitted now, I have some flushing agent so I can us a hat prior to cahanging the components

[RoverRevival]

i would start with a flush, but only replace with water just in case the situation doesn't resolve its self

[defenderman]

With antifreeze in the system at the moment do you think I could put the flush into a the system or empty & refill adding the flush to clear water rather than mixing the two elements?

[Vinny1979]

Shop around for a good deal on that lot, if you can get another cambelt for say £10-£15 I would be inclined to fit that as you will be removing old one anyway, just my personal advice, although I can understand why you would re use. You should be able to tell how good the water pump is when you remove it too. If its a k series may be worth replacing the inlet manifold gasket too if you are doing the thermostat and there is no evidence of it being changed its only £5 or so and a failure point. Others may offer better advice, but I have always took that approach to any k series car I owned ( a few year back now! )

[defenderman]

Thanks Vinny, I will have the cam belt changed, in fact the pump & thermostat can be changed at the same time along with the gasket you mention might as well get it all done in one go.
Thanks for the prompt response & the sound advice.

[JOHNDQ]

If it's a MK2 check the SAAB Valve in the heater hose very common problem

[defenderman]

Hi JohnDQ, I have a SAAB valve in transit right now when it arrives all the bits can be fitted at the same time.
Thanks for your reply.