B6 S4 4.2 V8 rear coolant cross over

[beerad]

Hey guys,
Had this pipe come off on my 2004 s4, I think its off the rear coolant cross over pipe, dumping all my coolant. I think some of the crossover pipe has snapped off inside the hose as there is not much left to push it back onto.
Has anyone else had this happen? I've had abit of a search havn't found any guides on cross over pipe removal for the 4.2, I'm guessing its a manifold off job to get some space back there.
This is the best picture I have, pointing down the back of the motor, behind pvc / oil filter housing.

Any suggestions appreciated!

[2004B6S4]

That hose has a plastic fitting on the end just like the two main radiator hoses. That plastic part is the broken bit you see, I'm sure the pipe itself is fine. Half of the plastic fitting is still on the pipe, so you'll need to pull that off, and half of the fitting is inside the old hose.
I had the engine out when I took out my old broken hose and replaced it, but I obviously had the engine back in the car when I connected that end of the hose to the pipe. I managed to do it from above with the manifold on but iirc I still had all the electrical stuff pulled away from the firewall, and getting that end of the hose connected was probably one of the hardest things I've had to do on the car. There is a vin split for that hose and I don't know what the difference is but I'd hope that the later part # has a longer hose, because mine was the early version and it was short as hell. a tiny bit of extra slack would be a huge help in hooking it up

[jettaowner718]

That's the heater core hose about $75 bux for new one easy to replace once u remove all hoses on top manifold does NOT need to be removed!


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[alcatranz518]

There are 2 different versions, but you will *most likely* have the "early" version, but still need to check to be sure. JHM has a great way to identify which you need (early or late). Just in case you notice the connector (or looks like) can be bought by itself for cheaper, don't do it. Don't try and just replace the connector itself, it won't work...I tried ...twice. Just buy the correct hose assy and be done with it.

You can change it out from the top, I did it and it just takes some patience. It takes about an hour or so, just depending on how corroded on the existing parts are.

Pull the whole rain tray off (covers the battery) and take out the battery for more room. IDENTIFY which of the 2 hoses is the one you are replacing, because it will be hard as hell to remove from the pipe from being attached since birth so don't want to fight just to learn you removed the wrong one. You may even have to cut it partially to get it off the pipe. BE CAREFUL when removing the hose because the pipe it is connected to is aluminum and will deform easily if you try using tools (so basically don't use pliers or similar to grab the heater pipe). Its not terribly difficult, but can be a fight and if you use the wrong tools you will crush the pipe, and that is a heater core pipe...if that gets screwed up then you will have to change out the heater core too. Once the hose is disconnected just feed it out of the grommet and down through the cowl (into the engine bay).

Then on the engine end, you have to move the pcv and driver side hose out of the way. Also helps to move the coolant expansion tank out of the way (not disconnected lines, just out from the bracket). This way you have some room to ride that fender like a porn star as your arm is back behind the engine to get the quick clip to unlock the coupler. I can use my fingers, but a small screwdriver will work, its sort of like an "e clip" or "c clip" where it just pushes out of the coupler. (you will see how on the new one what I mean and it will make sense). then the coupler will just come off, if its corroded from old coolant it may be a little tough but not terrible, you can wiggle it to make it let go.

The new one installs in reverse, just feed it up through the cowl first, then attach the lower coupler then re-clamp the heater core end. Make sure you use the special coolant Audi recommends or at least meets the "G12" or better spec for corrosion/ foaming resistance. 3 liters if I recall and top off with DISTILLED water. Once buttoned up and filled, start and let car idle with the heater on high and the expansion tank cap off for about 15-20 minutes after fully warmed up with the temp gage at normal reading (or until you see the fluid in the expansion tank stop bubbling). This will "burp" the air bubbles from the system.

I mighta missed something, but think that's most of it, the important stuff anyway.

[beerad]

Thanks for taking the time to write that up, VIN matches the early type so ill get one in. Cheers guys!