coolant leak - opinions please :)

**H3ndr1kD** · 11-17-2015 10:50 PM

Since a few days I had some issues with a leaking coolant system (I have a '08 A4 B7 2.0TFSI), tonight I finally had the time to put some uv dye into the system and fire up the uv lamp.

I personally think it's the coolant flange but please give me your opinions

**allstock** · 11-18-2015 01:33 AM

Is that a blacklight?...trippy.

**Ori0n** · 11-18-2015 01:41 AM

Neat trick with the uv light!

Would definitely be your coolant flange. I wouldn't wait fixing it. I know if you let this go too long on a 1.8T you eventually soak your clutch in coolant and that's never a good thing. I did this on my 1.8T, took an afternoon and it's pretty much blind back there so you do it all by feel.

If you don't feel like cursing at your engine for a few hours take it in to the shop! It's worth it.

**moyenecorniche** · 11-18-2015 04:54 AM

It's one of the main fails on the 1.8T motors that T shaped flange crystalizes over time from the motors heat. Once the molecular structure changes, the flange is no longer able to expand and contract with changes in temperatures thus cracks form as the flange disintegrates.
I have also had that problem with my A4. Solution is to replace the flange but at the same time inspect all other hard to reach connections in the rear of the motor and replace them. If one is gone, the others are not far behind.
You could also insulate the flange from excessive heat with header shield cloth or one of those little snap on blankets that Audi installs on some of the wiring behind the motor in the B6 S4.

**Sales@DriveAuto** · 11-18-2015 05:34 AM

Yep, most likely the coolant flange. Cheap part, a bit of a pain to replace.

**KJack** · 11-18-2015 07:02 AM

After you replace it, flush out that nasty green coolant and replace it with the proper G13 pink stuff. I heard that the green fluid is bad for aluminum engine blocks.

**H3ndr1kD** · 11-18-2015 11:17 AM

Originally Posted by KJack

After you replace it, flush out that nasty green coolant and replace it with the proper G13 pink stuff. I heard that the green fluid is bad for aluminum engine blocks.

I already use the pink G13 stuff; the yellow crap is the uv dye I bought from autozone. The label said I should use 1 oz for two gallons of coolant; given how well it worked I now would recommend 1/2 oz for two gallons of coolant.

**KJack** · 11-18-2015 11:43 AM

Originally Posted by H3ndr1kD

I already use the pink G13 stuff; the yellow crap is the uv dye I bought from autozone. The label said I should use 1 oz for two gallons of coolant; given how well it worked I now would recommend 1/2 oz for two gallons of coolant.

Oh cool. The photos threw me off when I saw the fluorescent green! Yes, I'd say the dye works great. I'm going to keep that stuff in mind!