prijedor

B6 A4 Heater Core DIY

I will try flushing it first. Does 2006 A4 2.0 T have any bleeder screws like older V6 cars?

Dolamite

You mean on the core itself? No

prijedor

No , not on the core. I was talking about bleeder screws/valves on coolant pipes.

Dolamite

There's bleeder screws, holes, valves in a number of places on various coolant pipes. Depends on which vicinity you're speaking of. To purge most of the coolant there's one under towards the front of the driver's side. The hose is coming from the t-stat and routes to the radiator. There's a small valve with a spigot that's partial obstructed by the intercooler hose. Problem with this is that it often gets clogged and even if turned(c-clockwise) it still will not drain.

Near the heater assembly, a bleeder for air purging is on the return(could be the feed, I don't recall right now) line heater core hose connected to an aluminum line, up against the secondary firewall. You can't miss it. The line is pulled back a few inches and the little hole(on the hose) will bleed coolant or purge air depending on the stage of your work. Sometimes it is difficult to move.

prijedor

Thank you Dolamite for your help.

Dolamite

No problem.

Just a note if your looking to purge air out if the system, the best and easiest way I find is the bleeder screw on top of the metal hardline connected to the upper radiator hose. The metal hardline is the one directly under the plastic engine cover smack dab in your face next to the pcv.


When engine is cool, open the coolant expansion tank, remove the small hex screw, forget the size sorry, clamp off the ventilation hose coming from the expansion tank/coolant reservoir (its the skinny one running towards you). Place your finger over that little breather hole you just opened and squeeze the upper radiator hose that's connected to the same metal hardline that your finger's on(this hose it the one near your waste line). Simultaneously squeeze once qiuick- then let go your finger. Repeat squeeze, let go etc. You'll hear and see air and coolant movement in out of the expansion tank. Do this till there is coolant gushing, not a tad dribble, out of that bleeder hole. Top off as you see the level dropping.

Don't place that screw on the engine somewhere unless you're using a magnetic pan! Otherwise place it outside and away from the engine compartment. It's easy to lose and also has a copper crush washer.

I do the above process to purge air after any coolant level dropping maintenance. Depending on the amount of air in the system and the amount of driving, you may notice a small coolant level drop. Anything over a week or two the you may have a leak and should check. It also will help to run the heating on one of those drives, especially after a heater core job.

Pertaining specifically to the heater core job, if you are bleeding air out of the core you should do both methods. The one where I told you about the small hole on the rubber heater line and the above. The air removal from the hole with the rubber heater line pulled back should be done with the engine on/heater on. Use a good hose pick tool and don't remove that hose all the way, just enough to let the air and following coolant to squirt out that little bleeder hole. It's best, of course, to do this before the coolant gets too hot. Hope this makes sense.