As the title says, I have a 2007 S-Max Titanium TDCi and the heater doesn't want to work below 60mph. Around town and on B-roads it blows out cold air but as soon as I'm on an A-road or a motorway and doing 60-70mph it heats up. Any ideas what is wrong with it? Cheers!

Does the temperature needle on the dash increase? On many cars it should hover around the halfway mark.

If it stays stuck on cold, it could be the thermostat that's stuck open.

I'm sure someone will correct me, but I THINK some of the diesel engines have an auxiliary heater - if yours does, that could be another potential candidate

Hi, yeah the temperature needle goes to halfway so does that mean that the thermostat is ok?

Hi,

I have this exact same problem on an S-max 1.8 TDCI Zetec. Very odd. Did you ever manage to get it fixed?

It would be nice to have some heating on without having to drive like a lunatic :-)

Thanks

Peter

P.S. I don't think it's the auxiliary heater (if I even have one) as the problem exists even when the engine is warm.

Hi Peter

No, still have the problem! I don't think I have an aux heater either, as like you say, the engine on my car is reaching normal temp but the heater still isn't blowing warm air! I was going to check the radiator water level so will let you know if anything changes!

I noticed yesterday that the coolant level was low so I topped it up and the heater seems to be ok now. Gonna keep an eye on it though in case it's leaking antifreeze!

I also topped up the coolant today and heating seems to be fixed. Now to find the leak :-(

Thanks

Yeah I checked the coolant level this morning and it's seemed to develop a thirst for it as it's empty again! Read somewhere that it could be a split in the plastic air bleed hose