MartinQ5

Hello,

Yesterday was a pretty cold night here in Quebec. -25C (-13F).

Today, the mercury went up a bit (-15C) (5F) but it is still pretty cold.

I was traveling with my Q5 (2010 3.2L) and all went well until I stopped for a few minutes while waiting for my daughter. I noticed that the interior was getting cold pretty fast. I put my hand in front of the vents and the air was barely hot and was getting colder. It all went back to normal when the car started moving again.

I just came back for a short ride (20 min) and same thing. But even worst, I could feel the aire getting colder when stopping at an intersection.

I checked for the water level (ok antifreeze!) and it is at the max level. The engine temperature is nominal (right in the middle)... What could be the problem?

Cheers,

Martin

Avant4Adam

heater core checking out maybe

Reggie

or the outside air was so cold and the auto setting was not recirculating the inside air

Dalancroft

65 and sunny here yesterday in Northern California! ;-)

uberwgn

Martin, the TDIs are known to do this as well on extremely cold days. There isn't enough waste heat being generated by the engine to keep up with your interior heating demand. I'm a bit surprised to hear this on a V6, but I suspect that's the issue.

MartinQ5

I just came back from another quick ride. Outside temp is -8C (18F).

Now I can say that stopped or traveling, if the engine is running under 2000 RPM, the heater core doesn't receive enough heat from the engine.

Is there a valve limiting the flow?

I checked with AC on/off, recirc on/off, manual fan control, automatic, defrost mode, heat sent up, down and in the middle. All the same behaviour. If the engine is under 2000 RPM, no heat coming out of the heater core.

Any ideas?

BTW, -8C is not uncommon here. I would have notice that since it if my fifth winter with my Q5... So this is not normal.

Cheers

Martin

Hockeymonkey

We just had our TDI in the mountains and temps hovered right around 10F and at night it dipped below zero. We never had any issues with heat in the Q5 TDI.
ok this is a shot in the dark but did you check the main car menu to see if the auxiliary heat is enabled? I honestly am not sure what it does but our was off and the dealer made us enable it.

MartinQ5

I do not have this function. Maybe it is TDI specific?

Thank you

drcollie

All care heaters work by circulating hot engine water through a heater core, augmented by a blower fan. When you are at an idle, very little water is moving through the core so on very cold days what you are experiencing is to be expected. Once you get moving the water pump is back up to speed and the circulation increases. Nothing is wrong with your vehicle, if you need more heat at idle then put the trans in neutral, step on the gas and hold the rpms around 1,800 and you will notice the warmth increases as the engine is running faster and putting more flow through the heater core.

MartinQ5

I agree with you that the heater core gets less coolant when the car is idling. However the amount of coolant is normally sufficient to heat the car interior. Otherwise why would there be people going out in the cold winter starting their car 15 minutes prior to departing to heat up the interior or why is there a lot of company selling remote starters if you need to be in the car to get the engine revving at about 1800 RPM? My other car, a Honda Accord gets hot on idle and never gets cold unless I turn down the heat manually...

As I said, I lived 4 winters with my car before and in all of them the temperature went below the -15F and never had this issue... So something is wrong. I am just trying to figure out what...

Thanks

Martin