Project 2.0tfsi , Engine rear coolant flange replacement guide.

I'm Just Rob.

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As in the title really chaps, my first short project for 2017 is on the joys of replacing this failure prone part.
Having found this part leaking on my old bus some months ago I have now decided it is time to sort it out, moreso because my coolant level is dropping faster than previously noticed so safe to assume if I don't do it asap it will just fail all together, and I don't fancy that .

It has been stated in numerous sites etc that it is a well documented problem on the 2.0tfsi's but having spent a lot of time today there doesn't appear to be a great deal on the subject over here in the UK, but its very well documented in the states, with a lot of very helpfull threads etc on a few sites.

Anyway, I thought I'd do a write up with my experience of the replacement just for us audi-sport users, well anyone really , just makes things a lot easier to find a thread than searching the whole wide web for hours and filtering out all the non relavant info.

So having had a good old search and having compared all the assorted methods of replacement it would seem to be prudent to obtain the following parts first.

you'll need the flange with the three O-rings , one is already fitted ( the engine block connection) , one small o-ring which is for the temp sender port and the third larger o-ring is for the heater quick connector fitting port.
parts: 1,2,4,5,6



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it is also a good idea to get a spare temp sender retaining clip , the two fixing bolts and the short section of rubber hose that attaches the flange to the metal tube section, none of these parts are really needed but since their cost is very cheap it is silly to not get them for the obvious reason below.
(1) the original screws fitted may be difficult to remove or get lost.
(2) The temp sender retaing clip may get damaged or dropped and lost.
(3) the short rubber hose section can be a pain to get off , so quicker to just cut it off and replace rather than fight with it for ages.

parts : 13 and maybe two new hose clips.

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It goes without saying you will need suitable tools to undo these screws and unclip parts etc in a confined space, what you use is personal choice , so what ever works for you.


There seems to be a few differing approaches to the fix , some seem to be easier than others, from my research the prefered method is that to gain a much better view and easier access to the area the Brake vacum pump should be removed ( only 3 screws ) and does make things a lot easier especially when dealing with the bottom quick connect hose , and removing the two fixing screws.

Just remove or loosen the parts around the bulkhead area that can be moved away or removed easily to make as much working space and access to the back of the block.

Draining down the coolant enough or clamping the hoses , all down to personal choice.

Rather than struggle with the small lenght of hose from the flange to the metal coolant tube and probably mess it up anyway, just cut and replace it with the new hose, many find it comes off easy other say it does'nt , based on a 10 year old car that has not had the hose disturbed before , easy removal may be far from the case, anyway , same applies take your choice.
Another area to keep in mind is the lower hose connection or quick connector from the heater, inside the socket that clips onto the flange their is an o-ring , dont skimp , use the new one.

It goes without saying that upon refitting the new flange etc , refitt anything you have removed and topup the cooling system.

I think that just about covers the main task, based on individual methods used some things may not apply or parts may not be required, all down to the person doing the job really.

So then chaps, I hope this guide is of some possible help to other owners afflicted by this problematic part.
I am about to perform this same job shortly and will be using the same method , if i find any shortcuts and better suggestions i will update accordingly.
I'll upload some decent pics aswell to go with this guide.

Please note , this is only intended to be DIY guide and anyone using it should be aware of this and make sure you are fully conversant with what is involved before you embark on the task/job, so good luck.

here are a few pics from other links as a starter in no special order, i'll be adding my own more indepth pics shortly when I commence my fix.

fl2.jpg
fl1.jpg
fl3.jpg
fl5.jpg
fl6.jpg
fl7.jpg
fl8.jpg
fl9.jpg
 
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I'm Just Rob.

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just updated with a few for starters.
 

Dani_B19

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Look forward to hearing your feedback on this Rob, I believe mine has also started to fail as I am very slowly loosing coolant and said area seems to be the culprit, going to try and have a better look tomorrow all been well.

On a side note. Would it be worth changing the vacuum pump if it needs to be removed to do this?
 

I'm Just Rob.

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I was contemplating changing the vac pump dani a few months ago , not that's it has failed but mine is very noisy now and probably accounts for more rattles from under my bonnet than anything else ,but yes if it needed doing then a good time to change it aswell, not sure they are that cheap though for what they are.
 

I'm Just Rob.

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Ok then chaps, update to this thread and its in two parts, preparation/getting organised etc and the replacement job itself.
so it's a long one but here goes, any feedback on part 1 would be good so I can amend any mistakes.
 

I'm Just Rob.

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B7 2.0tfsi coolant flange replacement guide Part 1 , getting organised .
Having now completed this job on my 2.0tfsi B7 i thought i would update my original thread with some clearer and more precise details on what is involved on replacing the coolant flange and what problems you may run into along the way.

I have set this out in two parts , first part (part 1) is all about what you need and getting organised, part 2 is all about the job itself.
Firstly it is not really a job for those of you who that are not really of a patient disposition as some parts and bolts etc can be very hard to get at let alone undoing and refitting them , if this is something that you are not happy with then get the job carried out by someone else and save yourself the stress and possibly an even bigger bill in the end.

The task can be broken down into specific sections many are not difficult jobs in themselves but due to the very restricted access to the whole area at the rear of the engine and the bulkhead they are made very difficult.
So then, if you are still reading then i assume you are going ahead with a DIY fix of the coolant flange.
What will you need then , well not a great deal of tools to be honest but some you may not have to hand in your tool box , It is probably a good plan to get all the bit together before attempting the job , just to make things just a tad easier rather than searching for a tool at the last minute only to find out you don't have it .

Here is what i used along with some sundries as well that may also be required.

1) A decent screwdriver set and in particular some long shaft flat head ones.

2) A mini ratchet / socket set and i do mean mini as space is very restricted around the flange face and bolts. Most decent kits include several torx heads etc , you'll be needed to use a T30 for the most part but other sizes will be handy.


3) a selection of hand lamps/inspection lamps etc to get some decent light in the work area, small LED hand torches are very good as they can be placed in differing positions around and below the flange to help see a bit more ( not that you will be able to see much anyway due to the postioning of the flange)

4) A small socket set can be handy for other fixings .

5) a selection of good quality hose clips , more will become clearer as things progress on which ones you may need.

6) selection of cable ties

7) plenty of thick blankets to cover both wings and front grill bumper area, you will find that during the job you'll be all over the engine bay from all angles and all most in it , it is crucial if you want to save you paint work from any damage that you cover it all properly.

8) antifreeze , you could save what comes out but topping up with fresh new coolant mix is all way's good, also a small container to catch the coolant that escapes, an old 5L container with the top cut off works very well and fits nicely in the engine bay beneath the oil cooler water connection.

9) some sticky tape, if you don't wish to loose your T30 bits and other screws then using sticky tape to hold them in place is a good plan.

10) this one was just a bonus for me to be honest, i have a very handy USB powered LED endoscope on a nice long cable, by using an old laptop you can guide the scope around the back of the engine and you get a clear view of what's going on, it does help but its just an optional part.

So that pretty covers the tools and sundries, keep in mind that the OEM hose clips can be a real pain to get of , i used a pair of adjustable plumbers grips to deal with them but a special tool is available if you wish to buy one, i replaced them with jubilee clips , your choice at the end of the day on this part.
If you have not all ready purchased the replacement flange ,don't forget you'll need the o-ring for the flange itself also the smaller o-ring that seals the sender , if you don't replace it or forget to fit one you hard work will be wasted as there will be coolant all over he place.
the parts you will need to be safe are:

1x N90316801 o-ring
1x WHT001688 o-ring
2x N91099101 bolts
1x 06D121101B hose
1x S032121142 clip
1x 06D121132C connection flange.

Note : you may not need all these parts , but , they are low cost parts and if you start the project and damage / loose any of them you will be stuck so better to play safe and get all of them, don't forget the part and parts you are replacing have most likely been on the car from new along so there is a very good chance that plastic parts have become brital and will just break, screws may be get lost etc....

part two to follow shortly .

coolant6.JPG
coolant5.JPG
B7 coolant2.JPG
 

Darren1983

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Grate right up mate. I shall certainly be following this at some point.
 

I'm Just Rob.

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And here is Part 2.

B7 2.0tfsi coolant flange replacement guide Part 2 ,the fix.

Having now completed this job on my 2.0tfsi B7 i thought i would update my original thread with some clearer and more precise details on what is involved on replacing the coolant flange and what problems you may run into along the way.
I have set this out in two parts , first part (part 1) is all about what you need and getting organised, part 2 is all about the job itself.
As all ready mentioned in part 1 this it is not really a job for those of you who that are not really of a patient disposition as some parts and bolts ect can be very hard to get at let alone undoing and refitting them , if this is something that you are not happy with then get the job carried out by someone else and save yourself the stress and possibly an even bigger bill in the end.

The repair can be broken down into specific sections many are not difficult jobs in themselves but due to the very restricted access to the whole area at the rear of the engine and the bulkhead they are made very difficult.
So then, if you are still reading this (part 2) then i assume you are going ahead with the actual DIY fix of the coolant flange.
What will you need then , well not a great deal of tools to be honest but some you may not have to hand in your tool box , It is probably a good plan to get all the bit together before attempting the job , just to make things just a tad easier rather than searching for a tool at the last minute only to find out you don't have it .

Right then, here we go.

Armed with all we know thus far commence by part draining down the coolant system, this can be achieved quite successfully by removing the coolant hose at it's connection point to the oil cooler, you will need to loosen the oem clip with grips or similar ( as mentioned in part 1) , If you use the old 5L container method to collect the fluid it will rest nicely just below the hose outlet. The hose can be a bit stubborn to get of so you may need to slide a tool up the hose a bit to break the seal, but don't damage the hose itself , dont forget to remove the expansion tank cap so the fluid can drain out properly.
as mentioned in part 1 , lighting is an important issue, you will need to get as much as possible in , around and under the working area, the more light you can get around the flange and its fixing the better.
You are working for the most part blind on the pump and flange screws with only feel to guide you, and trust me it is not easy, i'd even say all most impossible, but , with care and attention you will succeed.

2) To help gain as much working space as possible , undo and remove from its mounting points the expansion tank , it can be moved well away without disconnecting any hoses to it.
3)remove the plastic top engine cover

4) you will need to move the wiring harness that runs behind the engine and in the bulkhead cavity away from it normal location, this can be performed by cutting the cable ties to start with but don't damage the tie backing part as you can reuse it with a generic tie on the refit.
next unplug the sensors on the cables 4 in all, 3 on the top of the engine and the 4 being the sender on the actual flange.
lastly for the harness section you'll need to swing the coil packs and cabling away from the head, remove the two screws that hold the tube section on then unclip the 4 coil pack plugs , if you have freed up all the cable ties , removed the screws and unclipped all the appropriate connectors the whole harness can be moved to the side and frees up a lot more working space.
a word of caution here, with those sensors plugs removed now the actual sensor fittings are very easy to damage so take care .

5) Next comes the brake vacuum pump removal, if you don't remove this part it is all most impossible to get access to the flange as there is just not enough space to get a hand in the cavity let alone work beneath it, so off it must come.
held on by 3 x T30 bolts top right and top left and the 3rd bottom right top two are not to bad to get at, the lower 3rd one is a bit more tricky but is doable, this is when the mini wrench kit with the T30 comes into play, your working blind here so make sure your Torx bit is secure , if you drop it or you bit holder then you'll have a right old game retrieving them.
You will need it for all three bolts.

6) once you have the bolts out then you must pull the vacuum hose free from it's rubber socket in the bulkhead, use a firm and steady pulling motion to get it out , be careful not to damage any other parts in the process.
The pump can now be removed carefully.
Now things get a lot more difficult as you need to release the quick connect hose fitting that comes from the heater, the connector is held on by a metal spring and locks onto the bottom port of the flange, you'll need to use a long shaft , flat head screw driver to move the clip out of it locked position and then carefully pry the connector downwards , if you use a thin blade screw driver in the connector lip you will feel it click and the connector will push downwards and off.

7) right then, now that's off you can turn your attention to the two flange screws, now this is tricky and you need to use the mini wrench again with the T30 bit, you wont be able to see them to work on and there is only just enough hand room for one hand let alone two. You will need to adjust the wrench for the best angle and make sure the tip is secure, there is no way you will get anything else on the screws due to the lack of space and angles involved so once you located each screw by touch , careful get the T30 bit in the head and wind it out. It is not possible to get to both screws from the same side , you will need to do them from either side of the engine.
This can be a the most difficult and time consuming part of the fix, take your time and be careful, it's doable , it may seem impossible but have faith and you'll succeed.
next part, still reading this , good as there is a bit still to do.

8) Now there is a small section of rubber hose from the flange a metal section, it need's to be removed, there are two of the dreaded oem hose clip on it, you will really struggle to get them moved let alone of the connections, the solution is to just cut through the middle of the rubber hose.
You will now be able to remove the old flange complete with sender still fitted.

9) you will then need to remove the metal coolant tube that runs over the cylinder head , it's held on by 3 screws and another hose connection just above the oil cooler coolant hose (all ready disconnected), by removing this it is a much easier and quicker way of replacing that short rubber hose you have just cut in half.

Now that's basically the removal done, re-assembly is the reverse process of above which does also involve struggling with those screws.
a few things to be noted.

1) be very careful when refitting the flange screws and vacuum pump screws, your working blind again and it is harder to get them back in than it was taking them out as you need to get things lined properly or you'll cross thread the screws very quickly, and you don't want that, so you have been warned .

2) use new o-rings and don't forget to put one in the sender port or it will leak straight away

3) use the new sender retention clip as well.

4) i used decent quality hose clips on the really hard to get connections such as behind the head ect, it speeds up re-assembly and you don't have to fight to get things on, just slide the hoses on and screw up the clips, job done.
5) back to those cable clips that hold the harness secure, rather than ruin them ,if you cut justthe black tie strap only leaving the square tie body on the mounting plates, you can then thread a generic cable tie through the exisiting plastic tie block and then do the tie up as normal, the plastic block effectively becomes a mounting point, job done.

So that is about it , if you take your time and work through the job methodically you will be rewarded, rush it and make a right old hash of things and it will cost you dearly.
I've added some pics of my weekend fix, if you combine those with the other info i used at the start of this thread that's all you should really need.

I am not aware of any other easier method to be honest, you can't get to it from below except with the gearbox bell housing removed, doing the fix without removing the vacuum pump and other parts out of the way is all most impossible, that just leaves removing the cylinder head and that's a different job all together, so it back to the method that i have discussed.

please feel free to add any other info or advise me on any errors or better methods.
good luck
rob
flange fix1.jpg
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I'm Just Rob.

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Two days after my fix , all is sound and dry so a good job done , probably saved myself approx £350-£400 bill from a garage.
 

I'm Just Rob.

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well looks like this was a 100% successful fix, two weeks on and no loss of coolant at all , all nice and dry , onto my next job, the clutch and dmf on my Quattro.....this will be interesting...
 

Sygh2k

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just wanted to add, i did mine this aft and found the bolts holding the flange were splines and not torx.
 

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I'm Just Rob.

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thanks for that chap, I had seen a few other threads that mentioned they had splined bolts rather than torx, what year is your engine as I think the early units may have been splined and then revised to torx...
thanks for the update to this thread chap.

hope you managed to get yours done without any major probs.
 

Sygh2k

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ye i got it done in about 4hours, i had trouble removing the lower hose as i made the mistake of removing the flange too early.

i have a 55 plate 2.0tfsi avant
 

I'm Just Rob.

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yes , I think a few threads I read mentioned there 55's had splines but most engines had the torx , did you get the revised torx to refit, and yes that hose is real pig to get off , anyway you got it done which is the main thing.....how are your knuckles now...lol , not really a job one need to do more than once.
 

Sygh2k

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i re used the bolts, i have plenty in my toolbox if i came unstuk. i have some mechanix gloves which saved my knuckles, just not my arms. stil easier than the cambelt was mind you, i had to helicoil the tensioner
 

I'm Just Rob.

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What method did you use chap, did you manage to get access to it without touching the vacuum pump etc......just curious for future ref for others.
 

Sygh2k

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i removd the vac pump and ended up taking out the hard coolant pipe across the top as it was easier to remove the ends of those pipes then work on the short pipe from flange to hard pipe if that makes sense. i also removed the air intake and movd the expansion tank as much as i could
 
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