stein3

I didn't recognize the G12+ at first, this being my first Audi, so I was hopeful it was just day-old rainwater that had somehow come free when I parked it.

Nope. It looks like coolant to me now.

It was a steady stream out of the skidplate. There was enough steam to come out of the hood shortly after shutting off the engine. After opening the hood, there was steam coming from the left engine cover panel. The top all looked dry, so I'm assuming it was dripping on the exhaust.
I'm going to take the plastic skidplate off in the morning and inspect. Hopefully the problem areas are not dry by then and I can still track this down.

Are there any common coolant leaks that would happen this fast? It was perfectly fine while driving and the oil/coolant temp gauges were both fine when parked.

stein3

Sorry for the double post, but I can't seem to edit the OP.

Is the aux coolant pump on the rear coolant flange? I can't find any info on where the pump is, and I don't yet have a service manual.
Tomorrow I will investigate the rear coolant flange, aux pump, and possibly coolant crossover pipes if I can see them without tearing down the engine.

5v/cyl

Sounds like it's the aux pump. It's located under the intake manifold and sits in the V between the cylinder banks. When it leaks it runs down the back of the engine. It's a stupid location and kinda a pain to change since the intake manifold must be at least partially removed.

You can check by trying to see under the manifold with a flashlight. You probably won't be able to see the pump to easy, but may see the pink or purple fluid residue evidence of the leaky pump.

stein3

I ran the engine for a few minutes while my brother and I investigated with flashlights. The coolant begins to flow out shortly after starting the engine and ends up draining around the front of the transmission, but I couldn't see any coming out from the valley between the cylinder banks.

While it wouldn't be terrible to replace the aux pump, I'm no longer 100% convinced that it is the culprit.

cameltrophyallroad

Waterpump or thermostat housing are most likely, in that order. Sudden leakage is usually the water pump.

stein3

Alright, I guess I'll suck it up and just start prying off those fuel hose clamps. I need to either pick up a set of metric allen bits or find someone to borrow them from. I've never seen an intake manifold secured with allen bolts before.

Is it possible to get at the t-stat housing without removing the engine?

5v/cyl

The WP and T stat housing would leak from the front of the engine, so likely not your problem.

To get a better look remove the SAI pump. Sits behind the drivers side valve cover next to the coolant expansion tank. Easy to remove. Slightly harder to reinstall. With it out of the way you should be able to see under the back side of the intake manifold and probably actually see the Aux pump itself.

If any coolant under the manifold then it's the pump or one of the hoses under there. Options are to replace the pump or delete it with a hose from 034 Motorsport. If you delete just be mindful to always cool your turbos down before shutoff.

stein3

I'm having issues getting the fuel rails loose.
Are the injectors clipped in on both sides, or are their seals just stubborn? They seem to be what's holding it on.

Also, is it even necessary to remove the fuel lines from the intake manifold, or can the whole thing come off together? I wasn't able to find a walkthrough anywhere.

Also, there's a big conical thing wrapped in rubber with a little heat blanket that attaches to the bipipe. I haven't figured out how to unclip that yet, so I've just been swinging the bipipe up and back.

edit: linking this here so I (and others who stumble upon my thread) have it later
intake mani removal photo

5v/cyl

As in the photos you linked, you don't have to remove the injectors or fuel lines. Just tip the intake up on it's side.

The conical thing is removed by pinching the two sides of the clip and pulling hard. They can be very tight.

stein3

Finally had some time to look at the Audi again.

Is the valve cover gasket really this fragile??? Looks like I'll need to replace it just because of this one connector I tugged on. It sounds like most people take out the engine to do valve cover gaskets... nothanks


The bottom of this little sensor broke when I tried to remove the assembly from the intake manifold


Something cracked inside this electrical connector. Sounded like the brittle plastic that is covering some of the sensor wires throughout the engine bay, so hopefully its fine to run it.