Rear coolant flange replacement.

[Richy_T]

So it looks like I have this that I need to do and it's looking like it's a PITA so I'm just wondering if anyone has any tips that would make things a little easier. It looks like it's going to be unpleasantly tight in there.

I did find a howto video which helped a bit but it was for a B6. This car has a box above the flange on the back of the engine held on by about 7 bolts that looks like it would be useful to have out of the way. Is this something I can just unbolt, move out of the way then bolt back on or is it not that simple? I wouldn't mind knowing what this is too. (it's not my car but I have done the timing belt and other bits and pieces on it).

Thanks.

[Quattrological]

As the saying goes "the search is your friend." :)

I've got the 3.2, but a quickie search yielded:

https://www.audizine.com/forum/showt...coolant+flange

[Richy_T]

Thanks. The search was not my friend on this occasion. (I was searching in DIY and FAQs. Rookie mistake).

[Theiceman]

Tip.,. Leave the flange with the big heavy hose attached... Loosen off the hard pipe... Bend the hose and pull the flange above the engine.. much easier to get the clamp off there and clock the new flange in exactly the same position on the hose.
Unbend the hose and flange will sit perfectly held by the hose while you put the bolts in.


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[RPMtech147]

Tip.,. Leave the flange with the big heavy hose attached... Loosen off the hard pipe... Bend the hose and pull the flange above the engine.. much easier to get the clamp off there and clock the new flange in exactly the same position on the hose.
Unbend the hose and flange will sit perfectly held by the hose while you put the bolts in.


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Changing that outlet pipe was one of the first repair jobs I did on an Audi 100 years ago, and it beat the crap out of me; and made me anti-Audi for years. I still hate doing them.

You need very low pro torx tools.
https://www.amazon.com/Sunex-9726-Mi...%2C108&sr=8-13

and really, a bunch of inverted 12 points (triple squares) to work on any Awwdee to date

https://www.amazon.com/CASOMAN-4-Inc...xpY2s9dHJ1ZQ==

[Ray1031]

I replaced mine 3 years ago and today my wife calls me to tell me there's a huge pink puddle as she's getting out of the car on her way to the supermarket. I got there and saw that coolant is leaking on the back so I guess the damn flange needs replacing again, pita.... I've searched and I can't seem to find an aluminum one anywhere, is it available for the 2.0 engine or only for the 1.8? I really don't remember where I got the last one from. FCP Euro has some from as low as $15 to $100, should I get the OEM one or a cheaper version?

[Theiceman]

Changing that outlet pipe was one of the first repair jobs I did on an Audi 100 years ago, and it beat the crap out of me; and made me anti-Audi for years. I still hate doing them.

You need very low pro torx tools.
https://www.amazon.com/Sunex-9726-Mi...%2C108&sr=8-13

and really, a bunch of inverted 12 points (triple squares) to work on any Awwdee to date

https://www.amazon.com/CASOMAN-4-Inc...xpY2s9dHJ1ZQ==

Yup its amazing how much you learn after suffering through things the first time. I can do it in just under an hour know , but what a job it was the first time.
I think the key is lose early and just get the timing cover off and out if the way and pay 10 bucks for the gasket,
You are right about the mini ratchet set .
Those who have the timing cover off anyway I always tell replace the flange.

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[Theiceman]

holy crap what a weird coincidence .... just got a text from my son ... " dad you replaced the coolant flange 6 years ago today .. i just had a timeline pic pop up "

seems like only yesterday i was living that nightmare .. oh wait .. that was the clutch.

[67Twisty]

Don’t remove “the box above the flange” - that is the vacuum pump for the brakes and unless you already have an oil leak there you don’t want to disturb it. If you’re replacing the pump for other maintenance it’s a perfect time to replace the coolant flange at the same time as you’ll have much better access.

[Charles.waite]

Tip.,. Leave the flange with the big heavy hose attached... Loosen off the hard pipe... Bend the hose and pull the flange above the engine.. much easier to get the clamp off there and clock the new flange in exactly the same position on the hose.
Unbend the hose and flange will sit perfectly held by the hose while you put the bolts in.


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This. Those connectors can be a bitch to get off back there, bend it up and its much easier.

You need very low pro torx tools.
https://www.amazon.com/Sunex-9726-Mi...%2C108&sr=8-13

Something like this is absolutely critical for this job. Don't even bother attempting it without one. They're actually really useful tools to have around anyway.

[Charles.waite]

I replaced mine 3 years ago and today my wife calls me to tell me there's a huge pink puddle as she's getting out of the car on her way to the supermarket. I got there and saw that coolant is leaking on the back so I guess the damn flange needs replacing again, pita.... I've searched and I can't seem to find an aluminum one anywhere, is it available for the 2.0 engine or only for the 1.8? I really don't remember where I got the last one from. FCP Euro has some from as low as $15 to $100, should I get the OEM one or a cheaper version?

Always get OEM, the aftermarket ones have a tendency to warp and leak much sooner than OEM.

[Charles.waite]

Don’t remove “the box above the flange” - that is the vacuum pump for the brakes and unless you already have an oil leak there you don’t want to disturb it. If you’re replacing the pump for other maintenance it’s a perfect time to replace the coolant flange at the same time as you’ll have much better access.

How are you supposed to get your hands on the flange bolts with the vacuum pump in the way? I've removed my vacuum pump a number of times, removing it won't cause a leak unless you tear or twist the sealing o-ring reinstalling it. Just wipe some oil on the surfaces and you'll have no issues. Getting the vacuum pump out of the way (and ideally the timing cover too) makes this job WAAAAAY easier.

[67Twisty]

You can remove the flange without removing the pump. I did it using a mini ratchet and torque bit set. I’ve also replaced the vacuum pump (after the coolant flange job) and removed the timing cover for the rear chain and tensioner job on a separate occasion. Maybe I had an unusual experience but the vacuum pumps like to leak oil if you don’t keep the gasket perfectly aligned. Agreed it’s much easier access without it in the way.

[Theiceman]

How are you supposed to get your hands on the flange bolts with the vacuum pump in the way? I've removed my vacuum pump a number of times, removing it won't cause a leak unless you tear or twist the sealing o-ring reinstalling it. Just wipe some oil on the surfaces and you'll have no issues. Getting the vacuum pump out of the way (and ideally the timing cover too) makes this job WAAAAAY easier.

100%
And it's great opportunity to reseal it if you need to.
There is something to be said about giving up early and just getting stuff out of the way.
Plus you can check cam follower and address everything at once.

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[Charles.waite]

I'd rather spend 15-20 minutes and remove a few easy parts than struggle for 10-20 minutes with those parts in place. Yea you can do it but you're usually just trading time (usually not a big deal) for stress and frustration (something I have enough of in my life I don't need more, thanks). Maybe its just me getting old, haha. I like to work smarter not harder whenever possible, sometimes that means doing a tad more work to have a less frustrating or knuckle-busting experience.

[aluthman]

If you have a reason to remove the intake manifold (such as a carbon cleaning), do it at the same time and the coolant flange is much easier.

[Ray1031]

It turned out that it's not the flange but the heater core hose, it just snapped off... on my way to grab it from Autozone as the dealer doesn't have it in stock...

[Theiceman]

It turned out that it's not the flange but the heater core hose, it just snapped off... on my way to grab it from Autozone as the dealer doesn't have it in stock...

that is becoming more prevalent as these cars age .. but since you have dumped coolant anyway .....

[naps45]

….and did anyone ever source an aluminum version for the 2.0???

[Theiceman]

….and did anyone ever source an aluminum version for the 2.0???

yes there is one, and its on this forum somewhere.. but im good with mine.

[80sGuy]

Oh man, I remember this nightmare. Did the rear Flange and Upper Hose attached to it, Cam Follower, and Vacuum Pump seals. The job was like going through hell and back!
https://www.audizine.com/forum/showt...1#post14916063

[Theiceman]

Oh man, I remember this nightmare. Did the rear Flange and Upper Hose attached to it, Cam Follower, and Vacuum Pump seals. The job was like going through hell and back!
https://www.audizine.com/forum/showt...1#post14916063

still suffering PTSD I see

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[80sGuy]

still suffering PTSD I see

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You know it....and crossing my fingers everyday! But so far so good after 10 months with the parts.
Next up: Oil Filter Housing, adjacent Crank Sensor, and Breather Hose Tube from Oil Filter Housing to PVC.

[Theiceman]

You know it....and crossing my fingers everyday! But so far so good after 10 months with the parts.
Next up: Oil Filter Housing, adjacent Crank Sensor, and Breather Hose Tube from Oil Filter Housing to PVC.

i found the biggest pain in the ass of that housing was getting the breather tube off the top... i broke mine in the process. A bit hard on the back for those of us in advancing years.

[AudiB720TS]

I replaced mine with the engine out of the car and I remember saying to myself: “wow this would be hard with the engine in!” Because even the way I did it didn’t want to sit flush - so I’d say there’s real risk of failed installation if you can’t even see the mating surfaces.