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View Full Version : Rant about Coolant flange job and also still have some issues.



Lepper
09-24-2024, 09:59 AM
[headbang][headbang][headbang][headbang]

Finally had to do the dreaded flange and just want to complain about how ridiculous this job is. I have never had to do such a job that required so many other stipulations.

First you need triple square sockets, but not just any triple square sockets, but stubby ones to be able to access the flange bolts.

The access to the flange requires either muscles memory or extensive watching of videos, usage of cameras or mirrors to get the sockets into position. I watched videos for months before finally giving it a shot and it took me 5 hours.

The metal coolant pipes and the rubber coolant hoses get stuck together. I had to take a butterknife and go around the entire seal to get it to break. This was after an hour of using picks and flathead screwdrivers. The lower metal coolant pipe comes to a T and is very hard to remove while on the vehicle. I eventually settled for the short hose that goes from the flange to the metal coolant pipe.

The spring clips are almost impossible to get out out unless you have pneumatic hose pliers or needle nose with the perfect angle. I didn't have them and had to use my regular pliers, which took so long. Highly recommend these, would have saved me at least an hour.

I didn't remove the vacuum pump or lines. This would have made the job much easier, but the time saved would have been spent removing and reinstalling and I dont have a bit ratchet or swivel ratchet to take the pump off.

The fact that you have to replace the vacuum pump, or rebuild it and replace the o rings AND potentially the rear timing cover gasket just to make this job last is ridiculous. They purposely engineered the car so that oil would leak on to the flange and its connections and cause those appliances to fail too. The o ring in the coolant temp sensor, the heater core to flange o ring and the o ring on the flange itself will all fail and are potential failing points. You might fix one and if one of the others are on their way out, they will shortly and surely let you know right after you do one of others. In in a perfect world you would do everything at the same time, but I dont have money to do every single one of these jobs at the same exact time.

After I finally got everything back together, I turned on the car and my fan is now running 100% and doesn't stop. Seems to be a sign of a faulty Coolant temp sensor. Noticed it was leaking out the coolant temp sensor housing hole, so I swapped it with a fresh o ring which held at first but then started leaking again. I now need to replace the Temp sensor, and use the specific O ring that comes with it. I also have a new retaining clip.

The heater core lines with the quick fittings are a waste of money, gives the hose another failure point, and is another thing to replace. They could of easily ran a hose with a standard hose clamp from the flange to the heater core but they decided to make one end "quick" fittings that aren't quick at all because you have to have a pick to take the retaining clip out and they have an O ring which fails. Before the temp sensor started leaking again, it was spraying out of the quick fitting and now I need I need to buy a new flange to heater core quick fitting line.


To summarize, to properly and safely do this job, you need
Flange $9 FEBI
5mm(Coolant Pipe) and 8mm(Coolant Flange) Triple square stubby sockets. (Set of 6) $25
Coolant Temp Sensor $20
Retainer clip $1
T30 to take off coolant pipe
10mm to take off coolant pipe
Pneumatic hose clamp pliers $20-25
OEM Coolant Flange to heater core pipe (Supply) $90
OEM lower coolant pipe to heater core (less common to break, but if you might as replace it if you wanna be 100% thorough.) $54
Vacuum Pump O ring rebuild kit $20/New Vacuum Pump OEM $250
Timing cover gasket OEM $12
Coolant rubber piping $8
=$500 potentially if you wanted to do everything and had to replace vacuum pump or $270 if you wanted rebuild the vacuum pump yourself and it works.


Going to hope a new CTS fixes the issues but am concerned that it might be something else because my fan wasn't running before I changed the flange. I will have to order the heater core lines. Has anyone ever replaced just the quick fitting and crimped/put a hose clamp on yourself? Is the only thing holding the temp sensor in the retaining pin? There is no twist or turning or locking it into place?

Oh yeah I also broke the brake booster vacuum pump check valve line so im gonna need a new one of those which is about $70. Gonna see if I can RTV it back on, but its going to be need replacing.

Just glad that I am hopefully within $100 of this being resolved, but my body hurts now and I am going to bed. I stayed up all night doing this.

maleih
09-24-2024, 12:01 PM
Good on you for replacing it yourself. After reading how potentially complicated it was, I paid my local indie shop to do it. $350 including replacing the CTS. I supplied the OEM Coolant Flange though, so about $400 all-in.

80sGuy
09-25-2024, 02:57 AM
I agree, the rear Coolant Flange is one of the most difficult and involved jobs to tackle. I knew beforehand when I did mine back in March of 2023 I was ready and armed with new hoses, o-rings for the for CTS, vacuum pump, and fuel pump (also replaced Cam Follower) because I do NOT want to go back in there again! Regarding the fans coming on at full speed, happened to me after all the work has done. I discovered the plug connector on the CTS was brittle and completely broken into pieces inside its housing due to years of heat and wouldn't make contact. So I just manually connected the two wires (hot-wired) until the replacement housing arrives.

Now here's the thing, even after making contact you MUST use a code-reader and clear the code otherwise the fans will just keep on spinning at full force. It might clear by itself after a while but I couldn't wait and erased it on the spot while waiting for the new housing plug to arrive of which then I re-wired to the new part. After this ordeal I also ended up replacing the lower hose (adjacent to the flange to metal pipe) so most of my hoses are new.

Regarding those 'quick fitting' clip-on style hoses; they are strong and will not come off easily unless they are old and damaged by engine oil leaked on contamination. They're also extremely simple to tackle. Just use a flathead or pick-tool to lift and unpin it just enough and then pull the hose to release. You do not have to completely remove the horseshoe pin. And when you're ready, just push the pin back down all the way completely flushed and push the hose back in to connect until you hear the 'click' where the pins will lock itself from both sides. I never have to completely remove any of those pins. With my job, I use ALL genuine parts for peace of mind, and so far with zero issues.

Theiceman
09-25-2024, 08:13 AM
gees guy you didn't do nearly the amount of reading you should have ... i and other have put extensive information on here on how to do this job easy.. i do them in less than an hour now start to finish .. but as you say you learned a lot.

1. lose early , takes longer to work around the vacuum pump than to take it out.
2. take the timing cover off if you are comfortable as it will allow you to check the chain and pads and cam follower at the same time and do a complete service in that area .
3. have the right tools ... coolant clamp pliers on the cable work wonders.
4. loosen the coolant hard pipe.....
5. do not try to take the main coolant line off of the pipe behind the car.. simply undo the bolts ... pull the hose above the engine with the flange attached ... then you can easily remove the flange and replace it with the new one clocked in the exact same position .
5. unbend coolant hose and flange will sit perfectly lined up waiting for you to put bolts back in.
reassemble.


BTW disconnect the battery and touch the two battery leads together, this usually cures the constant running fan issue if everything else is plugged in and working ( CTS ). this is a common issue after this job.

Lepper
09-28-2024, 08:19 PM
I did my flange and thought I had a leak from the heater core supply line that runs off the flange, but it was actually the rubber hose with the spring clamps. I had forgot to replace one of the spring clamps but got it back on and I no longer am seeing water leaking onto the the transmission housing. [:D]

That being said, I noticed a leak from the front center of the car dripping out near the crank pulley. It seems to not leak that bad when the car is parked, but when the engine is spinning. you start to see the leak. I assume its coming of the water pump by the timing cover and just coming out the bottom via gravity. [headbang]

Only have been driving short distances to auto parts stores and keeping several jugs of water in my car to top off, but damn it I have had some bad luck lately.

After doing the flange without taking anything off, I am not too worried about doing the belt and water pump, but the timing has been horrible financially.

I do have heat back though for when it starts to get cold.

Theiceman
09-29-2024, 09:51 AM
I did my flange and thought I had a leak from the heater core supply line that runs off the flange, but it was actually the rubber hose with the spring clamps. I had forgot to replace one of the spring clamps but got it back on and I no longer am seeing water leaking onto the the transmission housing. [:D]

That being said, I noticed a leak from the front center of the car dripping out near the crank pulley. It seems to not leak that bad when the car is parked, but when the engine is spinning. you start to see the leak. I assume its coming of the water pump by the timing cover and just coming out the bottom via gravity. [headbang]

Only have been driving short distances to auto parts stores and keeping several jugs of water in my car to top off, but damn it I have had some bad luck lately.

After doing the flange without taking anything off, I am not too worried about doing the belt and water pump, but the timing has been horrible financially.

I do have heat back though for when it starts to get cold.yeah timing belt kit is on the horizon. you just need to be carefull of that water pump taking out the timing belt..

Sent from my SM-G973W using Audizine Forum mobile app (https://r.tapatalk.com/byo?rid=87676)

80sGuy
09-29-2024, 12:20 PM
.....After doing the flange without taking anything off, I am not too worried about doing the belt and water pump, but the timing has been horrible financially.

....
Just curious. What's the year and mileage of your car?

Lepper
09-29-2024, 04:47 PM
2005.5 2.0T manual. It was a 1 owner bought at 92,000mi and now at 122,000mi. Belt was done at 75,000mi.

Had to replace thermostat 18 months ago but other then that, just oil, tires and now flange and CTS.

Theiceman
09-30-2024, 10:17 AM
yeah the plastic bits fail on these cars.. usually caused by oil leaking on them though.

50k miles on a belt is a bit early .. but better 20K miles too early than .1 mile too late.

Lepper
10-01-2024, 05:52 AM
yeah the plastic bits fail on these cars.. usually caused by oil leaking on them though.

50k miles on a belt is a bit early .. but better 20K miles too early than .1 mile too late.

I think the belt is probably fine but I blew the seal on the water pump, so might as well replace the belt cause I have to take it off anyways to access the pump.

Theiceman
10-02-2024, 08:31 AM
100% just get the whole kit with belt, tensioner, roller water pump.

80sGuy
10-02-2024, 12:48 PM
Yep, might as well do all the stuff while you're in there with the front end off. While I'm about to tackle the TB, Tensioner, upper & lower Rollers & WP soon, I also got: N95 Valve, all the turn signal bulbs, and the main radiator hose and adjacent hoses.

BeefyA4
10-18-2024, 02:01 PM
I've learned from years of messing with vw/audis only ever use either another OEM coolant flange or an aluminum one. The aftermarket ones either leak right away or warp way faster than they should. And then it's probably a bit overkill but I only use OEM o-rings for the cooling system too, it's not that much extra. I've had too many problems like you after finishing a job and I fkn hateeee dealing with coolant. I also just cut off and replaced all those little stupid hoses that are stuck to the metal lines. Even cutting them off left huge chunks that had to be polished off with a grinder lol. I also recommend ideally doing it at the same time as your timing chain/belt and valve cleaning all at the same time. With the timing cover, intake manifold and alternator off getting to everything was way easier.

80sGuy
10-18-2024, 02:41 PM
I've learned from years of messing with vw/audis only ever use either another OEM coolant flange or an aluminum one. The aftermarket ones either leak right away or warp way faster than they should. And then it's probably a bit overkill but I only use OEM o-rings for the cooling system too, it's not that much extra. I've had too many problems like you after finishing a job and I fkn hateeee dealing with coolant. I also just cut off and replaced all those little stupid hoses that are stuck to the metal lines. Even cutting them off left huge chunks that had to be polished off with a grinder lol. I also recommend ideally doing it at the same time as your timing chain/belt and valve cleaning all at the same time. With the timing cover, intake manifold and alternator off getting to everything was way easier.

That's right! Not just the flange, I have been using EVERYTHING 'genuine' and yet to have any complaints to date. Most of my original parts lasted over 16+ years and the flange was still in superb condition when I decided to replace it just for peace of mind. So these newer revisioned parts shouldn't have problems lasting for at least another 12-15 years! By then my car would be over 30 years old, as for me....hoping I'll live as long as Jimmy Carter!

https://live.staticflickr.com/65535/52771154188_7ed9c1a367_c.jpg

New flange (top), old flange (Below)
https://live.staticflickr.com/65535/52786169075_1eb4539975_c.jpg

https://live.staticflickr.com/65535/52818662751_8c1688a9fe_c.jpg

https://live.staticflickr.com/65535/53157851986_f9b8e63e7f_c.jpg

CycloSteve
10-18-2024, 02:55 PM
Mid-Timing Belt, carbon cleaning, and all-hose baselining here.

The rear coolant flange and thermostat were replaced previously with VAG, and they looked great...the o-rings were borderline with perhaps 7-8 years on them (based on the PO records and date stamps). The only non-VAG I went with was the ECS aluminum rear flange. The o-ring on the water pump was absolutely shot (hence doing the TB service), and was worse than any other Audi I have serviced (1.8T, 2.0T, and 2.8 motors). Glad I decided to do the oil cooler, as it was fully clogged with pink goo; likely <10% flow. I suffer from while-you-are-in-there disease, thus have purchased all new VAG parts to do the job while they are still available.

Buttoned up the TB last night, and just waiting on the UPS guy to bring a few final bits for the injectors/intake.

Hoping to have the car back together this weekend and on the road. Like others have said, baselining to keep the car rolling for the next 10-15 years.