Coolant Hose Removal

[longlivenacars]

Hi guys, I'm working on removing a leaking coolant hose above the water pump. I was going to get it done at a euro car mechanic last year and what he told me was that he would attempt to fix it by removing half of the pump (the thermostat housing side) and change the hose. Gave me a contingency that he may have to remove the whole water pump if it doesn't work, and possibly get a new water pump in the process.

I put an e10 star bit on the 4 bolts on the thermostat side and it seemed a bit loose fitting, and I have rust on one of the bolts so didn't try it so as not to round off. Is it a number e8 or e9? I would have to buy those. Not enough space to fit my hand in to re +re hose even with remote hose clamp, with the water pump on the car. Hoping I can have enough space by just removing the thermostat housing side.

Has anyone that has done this successfully removed those four bolts and if so are they threaded into plastic on the water pump? For re-install would there be sealant required or just mate them back and screw together? I prefer not to remove the entire water pump as it seems a bit more involved but any input before I try would be appreciated

[jonan]

don't do it! the waterpump is made of fibreglass reinforced plastic and with age becomes brittle...you need to replace the ENTIRE pump or you risk it leaking when they put it back together. there are a few rs4 guys in 4agchat who've had their pumps break when attempting to remove those bolts

[longlivenacars]

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I'm working on removing the water pump to find my coolant leak and replace parts. I have the car in service position, but am having a hard time removing one of the hose clamps from any angle, even with remote hose clamp pliers. Would be a breeze if I had the whole front end off but prefer not to get to that stage for this project (a/c recharge and more work).

As Jonan suggested, I have done everything to avoid removing the little e-torx bolts that seem to be plastic threaded. If I take these off, I should have enough access to get the clamp off. Is there a way to get the clamp off without removing these? I could take them off if I get a new water pump, which I probably will buy, but then wouldn't I have to take the 4 little e-torx bolts off the new one too, which is something that is not ideal, in order to put the difficult-to-remove hose clamp in question back for re-install?

Based on the diagram I have uploaded, the port on the water pump in question (with the tricky hose clamp) is the one just ABOVE the small picture of clamp 45 (clamp 45 pic nearest the water pump body). This port can barely be seen with the pump in the car, so I am removing the hose clamp on the other end of the short hose, which is visible and has possible tool access as well right now (service position, rad is in place still). I think I am talking about hose number 9, but there is a slight chance it is actually hose number 5, this diagram trips me up a bit. One of these hoses is the one I am trying to remove that connects to the aluminum hard pipe and attached to the port on the water pump body above clamp 45 pic. Hopefully this is clear enough, and someone can give pointers on what tools or next steps I should take.

If you fast forward to 46:38 in my video, I give the best visual I can with the current access:https://www.youtube.com/watch?v=WBntYGAJQSc

Edit: Please do look at the video at 46:38, because it seems I have the hose discussed above already off. The port on the water pump for the one I can't get off doesn't even seem to be pictured on the diagram I have posted. No idea a this point if it is Hose 5 or 9 from the diagram. And if it's something other than a hose that's restricting the removal, please let me know, but for those that have done the job, I currently have TWO soft coolant hoses removed from the water pump body, aluminum crosspipe is unbolted on passenger side, all 4 water pump bolts are removed and I have slightly removed it off of the mechanism that operates it (input shaft?). The assembly is loose so it seems to be a hose causing the tension which is not allowing it to be removed.

Thank you all

[longlivenacars]

Bump

[longlivenacars]

To answer myself so this helps in future for those removing water pump in service position:

The dealer and a parts supplier emailed me the same pic I previously posted, which is not clear where everything leads to. Even got 5 other diagrams from dealer to piece together which hoses attach where, and still, some hose attachment points were not clear.

Forgot about this site, someone just posted it again in s4 forum. better than Audi diagrams (This will make it easy to purchase correct hoses):

https://audi.7zap.com/en/rdw/audi+rs.../1/121-121045/

^^ This shows with lines what everything attaches too.

In terms of getting the hose off: I'm still not going to take the thermostat side of the water pump off for access to that hose clamp in service position, as recommended by jonan, leaving that as a last resort. Just realized the simple idea of me holding the remote hose clamp end in place with both hands under the car, while another person pulls the handle to release the clamp.

I'll update if this works once I get around to it

[blubusdrvr]

I was able to do it successfully a couple of years ago and replaced all the hardware but I agree with Jonah, you may as well replace the entire unit while you’re in there. I was troubleshooting a slow warm-up issue and just wanted to eliminate the thermostat. It ended up being a check valve in the L aux radiator hose. (Part 3 in your diagram) These cars never cease to throw curve balls and baffle me.

[longlivenacars]

Thanks, I will change that hose too then. I ended up having to take the thermostat housing off and still had to cut the short coolant hose behind as its 'superglued' on to the aluminum pipe. Not superglued obviously, but is it corrosion on the aluminum pipe that causes this sort of binding?

[longlivenacars]

The end of hose number 9 in the 7zap diagram attaches to #10, the aluminum coolant pipe, if not mistaken.

This hose has bonded to the aluminum and with all prying and picking I haven't gotten it off:

My remote hose clamp pliers are princess auto, similar to harbour freight, and won't open the clamp far enough to slide off the remaining part of the odd shaped short hose. They do open it enough to rotate around the hose, thus not having any clamping force on the hose. Can anyone recommend a remote hose clamp plier with a tighter grab before I try dremelling the clamp off and maybe cause destruction

I have also thought of using a torch to melt the hose off partially or at least loosen the binding effect that has occurred before pulling and picking on it again. I am not a fan of trying this because anyone that has worked with aluminum knows that a bit too much heat can cause deformation

[Old_skool]

I have also thought of using a torch to melt the hose off partially or at least loosen the binding effect that has occurred before pulling and picking on it again. I am not a fan of trying this because anyone that has worked with aluminum knows that a bit too much heat can cause deformation

I use a hot-air gun (on a low setting - to minimise any heat damage to plastics or rubbers anywhere...) + 90 degree picks x2 + silicone spray lubricant can (the ones with the long flexible application tube) and try to spray under the flared open end when lifted by the picks. + somehow pull/twist on the hose as well if at all possible in tight spaces. Using curved-jaw adjustable pliers (see amazon link below) on a cloth at the hose-end also to try and twist it even slightly free can also sometimes get it over the line to freeing (on top of all of the above).

albeit If space allows for you to somehow get a flow of hot air in there from the hot-air-gun tip that is.

Same principle as a torch but less extreme... still a massive pain many times regardless, especially in tight spaces, but the above combo with bouts of hardcore pulling... and swearing... usually eventually removes the hose-end



link to pliers type>>

https://www.amazon.com.au/KNIPEX-87-...159697051&th=1

[longlivenacars]

Thanks for the input, will consider these options when I'm back at this job

In terms of the Knipex you linked, I've heard of these being good, but have usually seen people working with them with removed engines. That area for this specific job is very tight.

I think the knipex would only work if they have a mechanism that opens the jaws wider than the amount of handle input required by a good amount (Do they? I don't know this.). The potential issue is your hands taking up space trying to open/squeeze the handle AND the actual plier jaws in the area where the hose clamp is (May not be enough space). Saying this in comparison to how much you need to grab the handle on traditional pliers, and the respective amount the jaws open (These tools did not work for me). Hope this makes sense to the reader in maybe providing more input on this

[Old_skool]

Thanks for the input, will consider these options when I'm back at this job

In terms of the Knipex you linked, I've heard of these being good, but have usually seen people working with them with removed engines. That area for this specific job is very tight.

I think the knipex would only work if they have a mechanism that opens the jaws wider than the amount of handle input required by a good amount (Do they? I don't know this.). The potential issue is your hands taking up space trying to open/squeeze the handle AND the actual plier jaws in the area where the hose clamp is (May not be enough space). Saying this in comparison to how much you need to grab the handle on traditional pliers, and the respective amount the jaws open (These tools did not work for me). Hope this makes sense to the reader in maybe providing more input on this

Just re-read the entire thread and I understand that you already have the hose/s off, and are now trying to remove the entire water-pump/thermostat-hosing (black plastic unit).

I had a look at the diagram you linked to and it appears to be the same as this one…





If you are concerned about hose#9 (to back of pump AND aluminium side-to-rear coolant hard-pipe) I would just cut the hose and order a new one (ie that old "while you're in there" adage etc.) from the dealership… very small hose and not expensive even at oem dealer prices. Part # 079 121 057 H.

I cant get a complete picture of the space you are working with as (and correctly mentioned by you also) is that I have only ever done this with engine out… and currently my engine is out so cant even get a rough estimation of the space you’re working with
I can hopefully add some info that may hopefully be useful though…

In the process of the refresh I was doing before I put the engine in… I looked at this diagram and decided (in my quest to replace EVERY seal/oring I can get to) to open the pump and replace all internal o-rings (numbers 3 [079 121 119 B] & 5[079 121 119 C]), and also remove the entire pump from the motor so-as to replace o-rings numbers 10 (N 908 063 02)& 11 (N 910 089 02)… no sealant involved anywhere...




In relation to your aforementioned concerns regarding removing the bolts from anywhere on the housing so as to dis-assemble it… the compound is a glass re-enforced nylon… which is incredibly strong and quite de-formation resistant, and shouldn’t be particularly brittle… just tough/high density.
This is also why the bolts are difficult to turn/remove… due to the thread biting into a semi-rigid polymer that grabs onto the bolt along the entire thread (as opposed to metal that does not do this).

However… having said that… whenever I am concerned about stuck/seized/or snapping bolts etc, I use this…






Although it says ‘lubricant’ on the can, its ‘party-piece’ is that it is designed to thermally shock the bolt into expansion/contraction… and thus freeing the threads to make the bolt easier to crack/turn. So just spray the head for a few seconds and wait a bit, then undo etc. This stuff has saved MANY iffy-looking bolt situations, but i always spray the bolts BEFORE the first attempt to undo, as opposed to once an issue occured. Better to be overly pre-emptive than wish i had done it later etc.
I wouldn’t worry about it, give them a spray and and just go very slow (undo slowly), (and definitely get the perfect multi-point socket size to minimize stripping) as the rubber seals inside should ideally be replaced as they are definitely potential leak points (current or future).

To even further minimize chances of anything breaking then do this on a really hot day when the plastic becomes less-rigid/more-flexible... or conversely with cold weather bring the pump inside overnight with the heater on and allow it to 'heat up' overnight. This reduces the brittleness of any material, especially plastics, as it yields more before its snap/breaking point.

And lastly,
When I tried to remove the entire water pump (from the engine) even with my engine out… it appeared to be stuck on something… even though I could see every part of the pump, all bolts removed, all hoses remove, and it wouldn’t come off the engine. Took absolutely ages to pull free even with my engine suspended on a crane with 100% access to EVERY part of the pump and engine.
For some reason the way it connects to the shaft, combined with the super-fat orings, plus some other unknown element (to me anyway) even with trying to wedge the pump off with timber etc… this took a LOT of effort, and I actually slightly deformed/pushed-in the back of the pump (which is aluminium) so be very delicate trying to do this.

In short… the pump resists (more than would seem normal)
to being removed from the engine for some reason.



PS- I cant say for sure that those pliers will even fit into where you would need, but they are WAY better for hoses than regular pliers… this is due to being able to open the jaw size to whatever the closest dimension would be to the diameter of the hose to give you the best grip on the hose, and due to the design, you only need the one hand to apply pressure on the handle ie grip tightly and there is no need to additionally hold the pliers-jaws onto the rubber hose end (or whatever is trying to be gripped).

They are really handy, but possibly check them out at a hardware store first to get a better idea… like you said, its hard to communicate these things just through words sometimes

[longlivenacars]

Thanks for the reply.

I should have linked my more recent video to save some of the time you spent and other steps you put into the post, but I'm sure the info you've provided will be of help to others in case they run into difficulties I did not. I have already cut the hose off and removed the water pump. I also got to the maximum efforts of picking and prying before the hose remainder becomes to mangled to heat up and be able to grab so I have paused while figuring out the best way to do it. If you go to time stamp 2:04:00 and watch till 2:05:30, you will see the remainder of that short hose number 9 on the water pump side. Because you know what it looks like you can imagine how much is left inside that tight space attached to the aluminum pipe.

https://www.youtube.com/watch?v=iW4kWG2b3SM

Its interesting it was difficult for you to get the pump off cause of o-rings and the shaft mounting point. My water pump showed no resistance to the shaft it connects to, the hose 9 was the major preventer in my case to get the water pump out as one whole unit. This forced me to take the thermostat housing bolts off to start working on the hose. I have gone through that seal diagram you have posted but the main debate I'm having whether to rebuild the pump or get a full new unit is the metallic piece number 2.

I saw on FCP site that that piece is interchangeable on a number of audi models, and from looking at my old pump there is a weep hole on top. I don't have any crust or residue, but it is slightly possible my leak is a failed internal seal in piece number 2. Although in videos I have taken I got one stream of coolant on a hose higher up so I have ruled that out pretty much. The only other weep hole coolant repair I had to do was years ago on my sh*tbox Polaris quad, and I had to pull the seal out and seat a new one. My question is if seal #10 is the seal directly related to weep hole coolant leaks, in which case, I will consider rebuilding and reusing this one. If it isn't I will source that part #2 at least new (with all other gaskets/seals of course). Also do you think there is a bearing in part 2 for the impeller that could go bad in the future too?

In terms of the 5 thermostat housing bolts, I don't know if you removed this part on yours yet, but they do not thread straight into the polymer. You can see this in my video. There are metal inserts pressed into the polymer that the bolts go into. Some of these bolts were hard to access, but none of them gave me a fight. I was more conerned about stripping the threads on the little e-torx #8, but that turned out fine and the bolts seem pretty good quality, although I will replace them with new ones if I end up rebuilding this pump.

I will look more into the knipex to see if they will work in that tight area thanks for more info.

And for that loc tite product, I think this will help when try to get the DP bolts off my volvo which I have a 3"DP to install. Is it like penetrating fluid where you leave it to soak, or does it work in a shorter time frame?

[longlivenacars]

Bump. Anyone with reply to my above post ^^?

And other ideas on techniques to get the short piece of coolant hose off of the aluminum hard pipe in the tight area? Thanks

[Old_skool]

Its interesting it was difficult for you to get the pump off cause of o-rings and the shaft mounting point. My water pump showed no resistance to the shaft it connects to, the hose 9 was the major preventer in my case to get the water pump out as one whole unit. This forced me to take the thermostat housing bolts off to start working on the hose. I have gone through that seal diagram you have posted but the main debate I'm having whether to rebuild the pump or get a full new unit is the metallic piece number 2.

I saw on FCP site that that piece is interchangeable on a number of audi models, and from looking at my old pump there is a weep hole on top. I don't have any crust or residue, but it is slightly possible my leak is a failed internal seal in piece number 2. Although in videos I have taken I got one stream of coolant on a hose higher up so I have ruled that out pretty much. The only other weep hole coolant repair I had to do was years ago on my sh*tbox Polaris quad, and I had to pull the seal out and seat a new one. My question is if seal #10 is the seal directly related to weep hole coolant leaks, in which case, I will consider rebuilding and reusing this one. If it isn't I will source that part #2 at least new (with all other gaskets/seals of course). Also do you think there is a bearing in part 2 for the impeller that could go bad in the future too?

Yeah, my pump definitely resisted, and then once I got it off I couldn’t see anything that should have made it so difficult to remove, strangely enough.

I myself couldn’t tell you for sure that there are bearings inside the pump, as I did not disassemble it to that level, but I would assume that there would be bearings there, purely from an engineering design standpoint. Having said that, if it came to a point where I suspected an issue in that mechanism (the bearings/rotating parts) of the water-pump, I would just replace the entire pump (or part#2 on its own if available to do so), as opposed to try to dissasemble deeper to just remove a bearing, find a suitable replacement bearing, and then re-assemble… all of which would be difficult and not really worth pursuing in my opinion.

I only replaced all of the rubber seals/gaskets/o-rings as preventative maintenance... I myself didnt decide to replace any of the pump itself unless I was sure part of it was definitely failing and needed to be, but that is just my personal approach... I would think that any mechanical part will eventually fail, but my decision with this part (the water pump mechanism, bearing etc) was to just wait until it fails and definitely needs replacement.

In terms of the 5 thermostat housing bolts, I don't know if you removed this part on yours yet, but they do not thread straight into the polymer. You can see this in my video. There are metal inserts pressed into the polymer that the bolts go into. Some of these bolts were hard to access, but none of them gave me a fight. I was more conerned about stripping the threads on the little e-torx #8, but that turned out fine and the bolts seem pretty good quality, although I will replace them with new ones if I end up rebuilding this pump.

Ahh ok, its been a good 6 months since I removed the water pump and didn’t recall that the screws go into metal inserts.

And for that loc tite product, I think this will help when try to get the DP bolts off my volvo which I have a 3"DP to install. Is it like penetrating fluid where you leave it to soak, or does it work in a shorter time frame?

The Loctite should help with downpipe bolts… numerous times when either myself, or friends working on their downpipes could not budge the DP nuts/bolts, and then we used that Loctite, and were able to then crack the nuts and undo them. Some still ended up snapping at times but generally we were able to undo more of them than before using the loctite.

I think that it can also be used as a lubricant, but it supposedly actually thermally-shocks the bolts/nuts/screws into rapid contraction/expansion so as to free the grip of the threads…
Think of the screw/bolt being a balloon that is fully inflated and tight up against the hole/nut thread, and when you spray the Loctite it lets out some air to shrink the screw/bolt (but does this through freezing) to contract ever so slightly just enough to break its static grip at the threads. Whether this works as intended every time I don’t know, but it certainly has helped with stubborn bolts even when just sprayed on the head without being left to penetrate, say maybe around 30 seconds after spraying being sufficient etc. I've never left it to penetrate myself but if something is being particularly stubborn then maybe leaving it to penetrate could help.

[longlivenacars]

Hi all, thanks for the help to date on the driver's side coolant refresh. Here is where I am at now, finally got around to poking at this car a bit: https://www.youtube.com/watch?v=a9p5bQDXRHA&t=28s

Will keep this thread going as I progress, but questions before ordering parts are: Has anyone had an aux water pump fail on them, and if so , how did it fail? and IF I keep the old one in and it does fail , can I just connect the two hoses together from both sides of the pump and get some 'maybe needed' custom ecu tuning for that plug that goes into it and call it a day? Or does it have too much of a flow helping function in the coolant circuitry and needs to exist in the system for proper cooling?

Only asking this to help the NLA parts battle