Audi a4 2.8l no heat

SOURCE: 1996 1.8 ADR Engine Audi A6 overheating

Hi there, this could be a faulty thermostat but typically, these issues are caused by air locks in the heating system when the car cooling system is drained to take the head off.

The water pump may be working which is fine but there may be some big air bubbles in the pipes that carry the water from the engine to the heater matrix.

Have you tried without starting the car, taking off the water filler cap, not the coolant refill cap but the radiatpr cap. Not sure if this cap is actually on the radiator on the Audi or if there is one locatd closer to the thermostate housing, but once the cap is off top up the water to just below the neck and then squeeze the water hoses around the radiator to try and push water into the cooling system. You need to to squeeze quickly and with both hands to try and force water around the system and then slowly let the hose expand in your hands. Watch for bubbles coming out of the filler so that you can top up the water level again as it goes down. There will be a lot of bubbles if its really air locked and you may have to spend some time doing this. Keep toping up the water level though and once you can't seem to get any more bubbles out. Then if you can close the system again - i.e. put the radiator cap on and go for a ride. if possible find a steep incline where you can point the car up a steep incline and get the engine really reving to push the water round the system.

Go home - wait for the engine to cool and if the heater has not started to work on that trip, once the engine is cool, repeat the process with the hose squeezing to see if you can get more bubbles out, followed by toping up and so on.

If that really makes no improvement the worrys would be that your right that the thermostat could be bad although you should notice that with the temperature gauge moving up pretty rapidly and the car getting over hot if the thermostat is stuck shut. If its stuck open then it wouldn't stop the heater working it would just be slow to warm up.

It could also be the heater valve on the hot/cold switch where teh valve is not opening, and a last ditch issue would be that the water pump is not working.

My advise would be try and clear the air lock first. Also if you have a manual for the car (haynes manual), they normally talk to the correct way to refill the heating system to prevent the air locks. Some times there are venting points on the block that can be unscrewed to bleed the air out but for that you need the manual.

I hope that will at least help some - best wishes.

SOURCE: 2001 Audi A4 2.8 no or little heat

there is a valvve that lets the coolant thru the heater core when heat is selcted then when it is off it goes thru thur the return instead of the heater core i bet your car is running a little off if it is the vavle works of a vacuum line and the vavle has a crack in it

scott rimmer

• 162 Answers
• Posted on Mar 04, 2009

SOURCE: we have an audi a4 2.6cc , the heater only blows

sounds like the thermostat is not functioning correctly? either that or not in at all? thus making the water which would normally warm up quickly, warm up extremely slowly and on really cold days not at all? with a 2.6 engine your car shoudl warm up in record time?

SOURCE: looking for procedure to properly bleed an audi A4

You didn't say what year the car is or what other diagnostics you've done lately...My guess is the radiator core is plugged...If you want to tackle it yourself, buy a Chiltons repair manual at AutoZone or NAPA stores ($25). I suspect you'll have to order the manual.
Good Luck

SOURCE: bleeding a4 (b6)cooling system?

bleeder screw on metal water pipe above inlet manifold. loosen bleeder screw, fill coolant at coolant resivoir untill all air pushed out bleeder.