No Heat!

[jtman79]

I removed my bumper and front end today to change a bad crankshaft pulley! And now I have barely any heat! Any sensor that might trip this? I did loose my coolant and I refilled it and it's topped up, no over heating or leaks, no CEL. tried setting it to "Hi" and leaving the fan down to one, some heat built up but not much, gauge reads proper heat, and there was pressure removing the cap for the coolant reservoir. Thermostat (on engine) was replaced not long ago, just as maintenance. Help would be much appreciated!

[treysgreen]

I know the number one reason we lose heat in our A4's is a clogged Heater Core or air in the coolant. I am going to be doing mine soon. There is a DIY here.

[jacobsen]

Bad crank shaft pulley? what? what? what? how? why?

[viceprp]

Bad crank shaft pulley? what? what? what? how? why?

Yeah, how was this Part diagnosed "bad"?

How did you drain the coolant? I'm guessing you have a bubble.

[SlickFix]

I removed my bumper and front end today to change a bad crankshaft pulley! And now I have barely any heat! Any sensor that might trip this? I did loose my coolant and I refilled it and it's topped up, no over heating or leaks, no CEL. tried setting it to "Hi" and leaving the fan down to one, some heat built up but not much, gauge reads proper heat, and there was pressure removing the cap for the coolant reservoir. Thermostat (on engine) was replaced not long ago, just as maintenance. Help would be much appreciated!

Hi and welcome to Audizine. The most likely culprit to your low/no heat issue is air in the cooling system. This is a very common problem. There are two places to bleed: A bleeder valve on the hard pipe, and outlet pipe from the heater core, which lives on the bulkhead. The outlet pipe has a hole in the hose. You need to pull this hose out far enough so that air can escape through the hole in the hose.

If you use the forum search tool and search for "no heat" or google "how to bleed cooling system of a B6 A4" you'll find hundreds of threads on how to do this.

[customa4]

Here is the procedure for filling the coolant.

- Fill coolant expansion tank to the MAX line, then allow at least 45 min for the system to fill completley, add coolant to the expansion tank as needed to keep the level at the MAX line.


– Open bleeder screw -arrow- at coolant
pipe.



–Fill up with coolant until it flows out at
bleeder holes.

– Close bleeder screw.

–Detach rubber seal from plenum chamber
cover in direction of -arrow-.

– Detach plenum chamber cover -1-.



–Loosen coolant hose going to heat
exchanger and pull back hose until bleeder
hole in hose -arrow- is no longer blocked
by the connection.



–Fill up with coolant until it flows out at
bleeder hole in coolant hose.

–Push coolant hose onto connection and
secure with hose clip.

–On vehicles with auxiliary heater, switch
heater on (for about 30 seconds) and then
off again.

– Tighten filler cap on expansion tank.

– Start engine.

– Set heater/air conditioner to „HI“.

– Run the engine for 3 minutes at 2000 rpm.

–Allow the engine to run at idling speed
until the two large coolant hoses at main
radiator become warm.

– Run the engine for 1 minute at 2000 rpm.

–Switch off ignition and allow engine to
cool down.

WARNING
Hot steam or hot coolant can escape when
expansion tank is opened; cover filler cap
with cloth and open carefully.
– Check coolant level.
l
The coolant level must be at the MAX
marking when the engine is cold.
l
The coolant level can be above the MAX
marking when the engine is warm.