Heater Core Supply hose leaking

[waveblaster200]

Good morning,

It looks like my heater core supply hose where it meets the rear coolant flange is falling apart, 12 years of temperature cycles has taken it toll. I replaced the flange with a help of a friend a few years ago and solved the flange leak, now I on my own here and I need to replace this heater core supply hose, has anyone done this? I know I am capable of doing this just looks like a pain, Any tips or suggestions? I am going to change my Res this time when I drain the coolant out, also I see you can drain the coolant out just inside the right side of the bumper and guys are putting a hose on there so there is no mess. Any idea what size hose I need to drain it.

Thanks,
-Jon

[Corrado_Guy]

If you have done the flange then you have already done half the job so there shouldn't be too many issues. Pull the clamps back with pliers so they are on the hose and away from the flange first. The hoses really like to stick to the flanges you have to first get the hose loose. I find sticking a small pic or screw driver and gently work it under the hose to break the bond to flange works well. To drain or not to drain is the question here, if you are fast enough you will lose much less coolant than draining it but it will spill. The clean way is to drain the cooling system properly then replace the hose although you will still get some spillage because there will still be some coolant in the line. I have some coolant line clamps and I would put these on the heater hose and then remove it from the heater core and pull it off and pull it up so you get minimal leakage. When you pull the hose off of the head you will get coolant loss so you have to be quick here but it shouldn't be much.

If you do drain the coolant then you may want to change the engine thermostat and rad thermo fan switch while it is drain. Keep in mind that you will loose even more coolant when you take those out so use a bucket. Other than the hoses sticking to plastic flanges which are plastic and get brittle with age and taking care there is not much to it. I have always had the front bumper off to drain the coolant so I am not sure how it works with it in place (I also run a S4 bumper in case that makes a difference). Chances are good it will just rundown the inside of the bumper and into the drain pan so it shouldn't be too bad. If you are just doing the one hose you shouldn't have to drain a lot of coolant out before the flange is under the coolant line.

[gmx]

Pretty much covered, you will need soemthing like a small flathead driver or pick (bend a paperclip) to get the oring out in the heatercore hose.

AFAIK, it's a flared fitting and some great advice given to me before, is to clean out the hose provision. There's probably a lot of residue and crap in there esp as the o-ring passed it's seal-by-date.

[crunchie]

I cheaped out and got a new Quick Disconnect coupler instead of a whole new heater core hose. Mind you i thoroughly checked the condition of the hose and there were no apparent problems with it. Saved me a fair bit of time and money too as I only needed to pull the old coupler off and attach new one with a worm gear clamp. The old o-ring was the culprit and was the cause of my leak. The new quick disconnect i picked up from a local VW came with the new o-ring installed inside.

Here are part numbers that may help out. Although I'm AEB so not exactly sure if its different between years..

- Quick disconnect coupler: 3B0122291B

- Heater Hose Return (to coolant flange): 8D0819371H

Hope it helps!

[walky_talky20]

Only on an Audi forum does spending $20+ for a piece of plastic count as "cheaping out". lolz

Nice job. That's the repair I would do on mine, too.

[crunchie]

Only on an Audi forum does spending $20+ for a piece of plastic count as "cheaping out". lolz

Nice job. That's the repair I would do on mine, too.

amen to that!

i didnt have time to wait for parts to arrive so i had no choice but to go to the dealership.

here in australia it was either $32 for the coupler or $132 for the heater hose. im just lucky my hose was still in good shape!

cheers for the kind words Walky!

[SJorge3442]

Bringing this back from the dead. Is this the same coupler I would use on my 3.0? I really dont want to buy the whole hose if I dont have too.

[seanf86]

Yes it should be the same connector, my b5 and b6 1.8s both use the same connector, the one I bought however had a weird gap inside I had to put 2 o rings to fill the gap because it leaked when I installed it, been good for thr last month tho

Sent from my XT1058 using Tapatalk

[gmx]

Another bump.. to clarify, we must chop the original heater core hose and use a clamp with the replacement quick-connect coupler 3B0122291B right?

[audimac]

It looks as if my leak is coming from below the internal clip. Does this mean the hose is cracked? If not, How do I go about installing the Quick Disconnect Coupler 3B0122291B?