SkiBum2

Just finished put the cooling flange and everything else back together, and filled with fluid, and then started hearing dripping. Coolant is leaking out at the quick connect hose on the bottom of the flange. The quick connect hose matted up good with the flange, the keyed part of the flange slipped into the keyed part of the hose, slid on there and the metal retaining clip snapped back in.

Is there an o-ring or something I am missing? We're not talking about a weeping leak here... it is more like gushing (just by pouring coolant into the car).

Here is a diagram of the hose (#38 with the red arrow) I don't see any other parts, but the diagram doesn't show the metal retaining clip either (perhaps because they consider it part of the hose).

Any help is greatly appreciated.

lyleswk

I assume 1.8t...

I had the same problem. I solved by purchasing a new heater hose. There is a metal clip that comes as part of the hose that becomes weak and does not seal well. I was in a pinch and got at the dealer for $65ish.

SkiBum2

Yeah. 1.8T How bad is it to change that hose?

SkiBum2

ECSTuning.com has two options for the hose:

1. Mfg Part# 8E1819371B
2. Mfg Part# 8E1819373R

Any idea how to find out which one?

http://www.ecstuning.com/Audi-B6_A4-...oses/ES251685/

lyleswk

Easy change: spring clip on the bottom and screwed hose clamp connected to the heater core. Heater core hoses are under the cowl cover next to the battery and I will be darned if I can remember which one goes to the flange (core inlet I think) and which goes to the radiator. I believe mine was the 371 part, but I would remove the old hose, and compare pictures and then call ECS and tell them your situation and double check what you ahve found. I had the advantage of having both parts in my hand at the dealer.

BSCA4

Check to make sure you have the rubber o-ring there. Sometimes you may already have one in the flange and one in the hose so they double up or you don't have any then your will see leaking.

SkiBum2

Ryan. Does the o-ring sit in the pipe? Or should I slide it onto the flange?

There wasn't any o-ring on the new flange piece... but I did find an o-ring sitting on the transmission but I didn't know where it came from. It is slightly larger than the o-ring for the coolant temp sensor.

SkiBum2

I found that it is best to put the o-ring on the coolant flange. (If you put it inside the hose it tends to bend and push down in the hose and not seat properly.)

For those doing a coolant flange job, I would recomend getting an o-ring from the dealer/supplier for this lower hose. It is the same o-ring that goes on the temp sensor.

I have a feeling that this is where my coolant leak was coming from all along, but the gasket on the cooling flange (see part # 29 below) looked pretty rough, so I'm glad I did the coolant flange anyways.

As an FYI for those researching coolant leaks. If you suspect a leak on the lower hose to the coolant flange (part # 38 in the diagram below) you can replace the o-ring fairly easily. Take out the coolant resivor, remove hose # 21 from the coolant flange (optional, but it gives you a better view of what you are trying to get at), and then pull the metal retianing clip out on the lower hose (part # 38) you can then pull the hose off the flange and replace the o-ring.

2003amb

I did my coolant flange at approximately 58K miles by a shop. The shop didn't feel it necessary to replace the lower coolant hose attached to the flange (the one reference in this thread with the retaining clip)at the time of cooling flange replacement. I now have a pretty substantial leak at 109k miles on the vehicle. It has been a LONG 109k miles (new CVT trans, timing belt, waterpump, thermostat, 16 ign coils, the list goes on. This car just looks for a reason to break down on a monthly basis). As it stands, it appears the leak is coming from where the lower hose and the flange join.

QUESTION: Which should I replace?
A). The lower hose
B). The o-ring.
C). The cooling flange and the hose (which will likely eliminate any chance of leak.

Money is ALWAYS an object, and I can do the work myself which will save me a lot; yet if many of you are confident that a simple o-ring will solve the leak problem, then I am going to go that route first and foremost.

INSIGHT ON THIS IS WELCOME.

Attached is an image of the situation. The moisture/fluid on the top of the cooling flange is leaked oil from a worn valve cover gasket - an issue being remedied tomorrow. The fluid on the bottom of the cooling flange and the white streak along the bottom of the lower hose is coolant (white from the light of the flash reflecting off of it).

lyleswk

I had the same problem. Thought my coolant leak was the flange and after I replaced the flange, still had a leak which was actually worse after the work. It turned out to be the heater hose that connects to the bottom of the flange. I diagnosed by wiping everything as clean as I could, started the car, and then looked with a flashlight. When I compared the new hose to the old one, it was obvious the clip that secures the hose to the flange was the culprit. The only way to get the clip is to buy the hose. I purchsed one from my local dealer becuase the leak was severe at this point and I needed the car in service. Cost was somewhere around $65. ECS Tuning or your favorite parts house should be cheaper. Fairly easy to replace even though replacing the clip is a bit of a blind operation. Clamp on the heater core side is in clear site once you remove the cowling cover. Make sure to bleed the cooling system when you are done!