Blowers on cold, but hot from below..

morning all, last night while driving in very muggy and warm conditions on the M2 in the 300tdi, i decided it felt awfully hot in the old rattler so i had the blowers on cold and set on the dash vents. This was all well and good but the ol girl was roasting in the footwell and as we know hot air rises so it was getting warm in the motor (didnt want to undo the window before anyone asks as im not a fan of the wind noise on motorways). Is there any reason as to why id be getting very hot air from below, around matrix, even when the vents are on cold??

Cheers all

Maybe the dampers are not closing off the matrix, have u checked that?

Unless you have A/C the temp through the vents on cold will be similar to the outside/external temp, what ever that may be.
Plus as it was a sunny day you can add the temps through the glass into the cab, plus when u slow down heat will riseand enter into the cab from the engine and transmission.

Now have I sold u air con.

Seal from matrix to ducts??

IFIAK the hot/cold is via a flap that pulls air either straight form outside, or via the heater matrix, id suspect the seal from the matrix to the duct has failed, hence the warm air coming form it, while you still get the expected temp from the vents