1.8T Coolant Return Hose Badly Leaking - URGENT PLEASE HELP

[Skezza]

Hello,

It is of vital importance I get some advice here..... because currently my A4 is completely immobilized. It can't be driven to the garage because it is failing to retain water. Best I could do is arrange it to be towed unless I can either temporarily bodge fix or replace this part. This is where I hope someone will help here.

The car has been losing a very small amount of water for a good 2-3 months but nothing serious. It's been hard to diagnose the issue because it's been so wet in the UK. Saturday, things took a turn for the worse and the coolant began to drop significantly on a drive home. I was able to top it up but within minutes the warning was back on. With a bit of luck (turning the engine off at lights and coasting with it off etc) I hope I've not completely destroyed the engine.

The part that has failed is this:
New 06B121497F Cooling Hose for VW Passat Audi A4 01-06 Audi A4 1.8T | eBay

I will phone Audi and get a quote on this part, although at £10 from China I have a feeling Audi will want 10x as much Standard.....

I have a photo. Most of the water was leaking from the rubber hose. I've removed this, trimmed some of the frayed ends, re-inserted and it actually seems a lot better. I could probably crush that metal a bit using some vice grips. However, I notice there's a copper washer and it looks like it might be leaking from there as well. It's really hard to tell as you'll see.

Could I use some RTV around that copper washer and see if that seals it a bit more. Maybe put some RTV around the rubber pipe as well? I know it's not recommended and will only ever work as a temporary fix but it's really important. If you have any advice, please don't ignore this thread. I'm desperate at this point, I'm having to take time off work etc.

[arman123]

for a temp fix i would use this Self-fusing Silicone Tape

Permatex How-to: Self-fusing Silicone Tape - YouTube

[Skezza]

Thanks. How long would such a fix realistically last? Would it do a few days?

[arman123]

i think it will do more than a few days if you put in on properly remember the tape does does not stick to surfaces it sticks and bonds to itself wrap it on tight and stretch it for a good bond

[Crasher]

Yes, £92.17 from Audi. That one has failed by what looks like external oil contamination and it looks like it is about to blow off.

[Skezza]

Yes, £92.17 from Audi. That one has failed by what looks like external oil contamination and it looks like it is about to blow off.

Is that part pressurized then? Is it the return line or the feed in?

When you say external oil contamination? Is that oil dripping onto the rubber pipe? Or is that oil on the metal connections? Or is there oil in the coolant ? I'm amazed how little info on this part is on the Internet.

One thing I've noticed is the actual pipe with two metal connections is a push fit job and having removed it, it has a sort of, tapered fit. I wonder if I could replace just the pipe part. Has anyone ever tried this or do most just jump at the new part? This is where the fun of experimenting could begin.......... I might buy one of those el-cheapo jobs then see if it can be done, if it still leaks buy the Audi part and replace it properly.

[Skezza]

So I'm going to go a little more into detail with regards to what I mean @Crasher - I do love an experiment though. I don't mind too much being a crash test dummy for this kind of stuff either. At the end of the day, if nobody ever tries this, nobody ever finds out. The part is essentially a coolant hose connecting what I assume is the flange for the turbo to the flange for the intercooler maybe? I have to hope that i've not caused any lasting damage by getting it home, but one thing i did notice was it was still pouring out yesterday morning so there must have been some coolant in the system. Whether there was enough? I dunno, I'll have an oil change as soon as the car is fixed though. I guess I won't know if my turbo is ****** until, well, it's ******

So the standard procedure for this part is to replace the whole thing, at some difficulty. Seems you possibly have to remove the turbo, or bend your hands into unnatural positions and use a variety of weapons to get at one of the bolts. However, I spent some time looking at the actual hose yesterday and I'm wondering if it was originally designed to be replaced itself? The part cannot be purchased from Audi (I went to a dealer and asked) but you can easily disassemble one of the cheap aftermarket ones in my opinion and just the design screams modular. Just because Audi decided not to sell the hose doesn't mean it wasn't originally designed that way. It may have not have been cost effective, but with the cheap copies knocking about, you could easily replace the hose while keeping the important parts OEM. Let me explain further:



I wanted to see if the two circled parts are screw/nut and could be tightened up. Not so much the one on the left which isn't leaking, but the one on the right, which clearly is from the join (as seen in the second photo in the original post), so got under with a set of pliers. I quickly realised it was neither of those things..... it's nothing more than a push fit. Both hoses push directly onto a couple of 'tapered'/staggered ends.

I suspect it's designed to be a one time push connection so I would need to be really careful removing from the aftermarket part, maybe some heat and patience will help. The rubber hose is as a good as ****** at one end anyway and I'm facing either tow or turbo off job so I don't see this as much of a risk at this point. I removed the hose which I had reconnected by pushing it in, and then removed the push fit. It's quite tight but it does come and this is what you might see:


This dropped out. At first..... I thought it was maybe a washer..... but it's too big isn't it? Then I thought it was a seal perhaps.......? I don't think it's either of those two things however...... . That's part of the hose isn't it? You can see from the irregularity. The hose is clearly glued into this part and has now perhaps worn through where the full break is and then sheered off causing the massive leak?


So this part above I assume has the hose glued into it. So obviously the next question for me, is what do they use to glue coolant hoses in? Could you simply just cut the frayed ends off that rubber hose using some genuinely sharp cutters (I tried scissors but they're not sharp enough) and glue it in with black/red RTV? Maybe some Indian Shellac compound? Permatex 20539 Indian Head Gasket Shellac Compound: Amazon.co.uk: Car & Motorbike

I'm reading up on the best product for this job. Apparently RTV doesn't have the adhesive qualities of Indian Head Gasket Shellac compound? Thoughts?

The alternative of course, is to just try the pipe from the other one. However, I am wary that the other end of this pipe appears to have been smeared in some kind of silicone glue as well (hence the colouring). It could be a nightmare to remove.

I got back under the car this morning I'm thinking that de-greaser on the connection here and give this a go before we start throwing the baby out with the bathwater. Note the broken and jagged edges on the hose. Surely a sign that my assertion about the ring of rubber above is hose after all?



I must say, it astounds me that absolutely nobody has actually had a punt on this. Not every fix has to be over complicated!!

[Crasher]

You could repair that with some Goodridge push on hose, it is only at coolant pressure so around 5psi, the main criterion is the minimum bend radius capability of the hose. Even then I would supplement the barb retention with a hose clip.

[Skezza]

You could repair that with some Goodridge push on hose, it is only at coolant pressure so around 5psi, the main criterion is the minimum bend radius capability of the hose. Even then I would supplement the barb retention with a hose clip.

That's the plan.

Regarding the Goodridge stuff: Link

Blue or black, do you know? I can measure if needs, but it looks like blue has a slightly smaller diameter?

[GeorgeE]

That pipe was crimped on to the barbs in the same way as a hydraulic hose is assembled, so not really designed to ever come apart. No, Audi will not have it as individual parts, they will not have the kit to crimp it together in their workshops, they just fit a new assembly.

That said, as Crusher has already pointed out it is only at coolant pressure so nothing stops you using a pair of jubilee clips and a length of suitably sized hose to put it back together, or even at a pinch as a temporary fix you may get away with trimming the ends of the rubber pipe you took off and refitting it (though it may now be too short). Audi don't do it like that because in a factory a pre-assembled pipe is quicker to fit and more reliable.

Now it is stripped apart like that, any form of sealant tape is not going to help.