BSCA4

About a year ago, I had the head gasket gave up on me. Everything was great after the head was redone. Yesterday just found a small puddle of coolant seem to be from behind the engine. Is the coolant flange gave up on me after a little over a year?

Catamount90

Sure, but the only way to really know is to trace the drip. Front of engine, back of engine?

Impossible for any of us to know without you providing a photo or description of the drip location.

BSCA4

Sorry no pic as it is dark outside. Definitely from the back of the engine. Not a lot, may be an oz or 2 oz (why so little?)

Gingerbread man

Check out the flange. It should be obvious if it's leaking.

The head gasket will cause oil to leak onto the coolant flange. The O-ring on the flange will expand (the engine oil does that) and it'll start leaking. Ask me how I know. I also had a very small leak for about 2 years (~250 cc of coolant per 5000 km). It starts small but can get nasty if the O-ring goes away completely. At the point I had it done, it was impacting driveability.

If you do it yourself: there's going to be coolant everywhere so have G12 ready and a hose to wash it all off (and a warm garage would help). Those clamps are also a pain so have the tool for them or get replacement clamps with screws (stainless, of course).

BSCA4

Strange, I drove to DMV this morning (about 10 miles), no leak. Got home, a few drops same location. Open the hood up: I see bubble on the top of the coolant reservoir. I think it has a small cracked, so the pressure escape create the bubble. Can that cracked create issue? I will replace it tomorrow together with the coolant flange.

speedster_104

@gingerbread man... How difficult is it to change this this flange. I have this exact problem. Do you have any tips? Or DIY write ups? It seems like a very difficult location to remove and replace this flange. It seems this way with all german cars.

Gingerbread man

I decided not to do mine because it involved head gasket removal and an oil valve replacement as well (that slow oil leak caused havoc in the back) and it was getting a bit cold out here. I'm not sorry I didn't do it myself. It took the senior mechanic there about 4 hours to do everything (which means it'd taken me at least 8 hours). Bear in mind this job involved the head gasket too. But I was there all along so I saw everything.

Here's a pretty good DIY for the flange alone:

http://www.audizine.com/forum/showth...Coolant-Flange

Just have replacement stainless clamps ready (like the guy in the DIY). They're cheap. Also have some coolant (G12) because a whole bunch leaked when mine was done.

BSCA4

Just did it today, not hard but lot of thing to take off for the flange (B5 flange is much easier to replace. The article is great but I think it missing one oil line also bolt to the flange (bottom nut). Also replace my expansion tank. I did see some white trace of water on the bolt but the o-ring gasket on the flange look good. Not sure why it leak.

Gingerbread man

Groovy!

speedster_104

It was a test of will today, but I did it. Took me 6 hrs to remove and replaced the flange and y-hose above the flange. I don't know what these German engineers were smoking, but they shouldn't have been designing this car. Who the hell makes a sealing flange out of plastic?!! This part should have been aluminum or some higher grade plastic. Somebody should make replacement part out of aluminum. And why is it in such a f...Ed up place?!!!

So this week. I've replaced a crappy battery, replaced crappy b6 rack with b7 rack, coolant flange and a few check valves.. Freakin eh! If I wasn't the only owner of this USP 6spd A4 it would have been replaced by my previous car, an 85 trueno.

Thanks for the tech posts and references everyone!