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S4 Coolant/Intake/Boost System Help Req...

MiniMental Apr 11, 2018

  1. MiniMental

    MiniMental B5 Nut

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    Howdy,

    I have now stripped my car back after a catastrophic coolant leak lead to a flatbed home, IM off etc and found the aux pump has broken in half.

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    I have found most of the bits but i'm in need of a couple more i think, But not sure. I'm going to flush the system out whilst its in bits which will make a mess but be worth it. At present its full of rusty water and goldish glitter. Presumably from the previous owner trying to stop the aux pump leaking... Its well crusty... What can i use to remove as much old radweld and rusty **** as possible? I don't mind running it for a while and then re-draining and flushing again etc as long as its done properly. It'll be getting a new header tank as mines stained orange from the radweld i think.....It looks white from the outside but cant see coolant in it when its full.

    1) I think the power steering line is seeping next to the pump ferrule.. It seems oily but i've not been losing any fluid.. What do people think based on the picture.

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    2) I'm planning on stripping the metal coolant pipes off, and repainting them etc.. Is there anything i should note when i do this? I'll get new "O"Rings from work... Is the pipe which runs behind the timing cover removable without touching the timing cover etc? if not, ill just leave it. What can i paint them with also? Want it to last...

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    3) I have a split in the hose from the expansion tank tee. It runs to the LHS of the metal coolant manifold.. Does anyone have one of these knocking about? Its not leaking but split through to the braid as below.

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    4) I'm gonna strip and clean the intake manifold. i'll replace all the injector "O"Rings when i do. Im debating painting it. Is there any specifics to this? or just a bit of red oxide primer and some heatproof paint in my colour choice?

    5) I'm going to replace all the intake mani bolts with studs and flanged lock nuts. is there any reason i shouldn't use Stainless into the alu head? This has been debated long term online in various forums but cant find a definitive answer. Plan so far is to get M6x35mm SS Grub Screws and SS Nylock flanged nuts for when i put it back on. I'll be doing this to the rocker covers also when i do the seals etc in summer.

    6) Are the wastegate/boost reference lines likely to be leaking at 19yo? ive had a boost leak i cant trace for a while, not a big one, but i can hear it hissing a lot when i'm on the pedal. "F" Hose has been deleted and TBB is a new Mishimoto one. Im going to also strip the intercoolers off and test them and their hoses at work. I haven't seen any leaks as yet. It seems the only place i haven't checked is the boost reference line from the snail and the turbo/compressor outlet joints. Is it going to be easier to drop the subframe down to get to it all and check it out? i have realignment pins somewhere to line it back up.

    Any help is appreciated as i wanna do it right and hopefully get my car back running normal. I need to do this and maintain it before i'll allow myself to get it mapped.

    Cheers
    Aidan



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  2. QuattroCalum

    QuattroCalum Well-Known Member Team Avus Silver saloon Audi A4 quattro Manual

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    It would be a good time to replace the injector seats while your it, I'd expect to see some staining around them as evidence of leaking ( they are plastic after all)
    They will break half way out but if you have the intake off anyway that's not a problem.
    I replaced the ones on my 1.8t and it ran smoother and gained an few mpg as well.

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  3. pilla

    pilla Old ones are the best ones

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    With regards to flushing the coolant, I ran some liquid washing detergent through the system after my oil cooler went, had to give it a few fills and drains via the radiator drain plug but got there in the end, theres no oil in your so it shouldnt be too difficult. Flush it a few times.
     
  4. MiniMental

    MiniMental B5 Nut

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    Well then, it’s been a journey this past month or so.

    I had a major incident sitting in traffic in Swindon, I thought it was on fire at first. So relieved when I saw coolant spewing out of the valley..

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    Long story short, Aux Coolant Pump had broken in half...

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    So, off it all came which just progressed into removal of everything. I was gonna paint the coolant manifold but when I cleaned it up, it was actually in really good condition so I haven’t bothered... All new ‘O’Rings fitted, got sick of looking at flaky aluminium so I’ve brush painted the intake manifold as well, all new injector seals etc etc...

    So, it’s had:
    New Aux Pump
    2 710Ns fitted in place of the afore mentioned DVs
    All new coolant seals in valley
    All new injector seals
    New gaskets for TBody and IMan
    New 90deg pump switch (blue one)
    New O Ring on lower rad fan switch
    New DV Vac lines
    New Turbo Oil Feed top banjo seal rings

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    Re-assembled it all on the kitchen side while it rained this morning, the rebuilt the engine bay through the afternoon... Been a good day really, need to coolant it up and run for a bit then drain and refill to flush it through. Could do with a good flushing agent tbh to fill it with but I have 20L of concentrate so it’ll do.

    As it happens, I got lucky, I found a cable tie head and a tin label inside the intake ports on LHS head before I put the manifold back on, soooo glad I looked, I removed these with surgeon like precision and then bodged the hoover and hoovered them all out just to make sure....

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    Never managed to run it today however....

    I’ve also removed the passenger boost pipe between turbo and intercooler to chase a boost leak I’ve been having, found no issue at all with the hose and got a bit stumped.... I then looked again today before putting it back together and found that I could just see the issue...

    Passenger side Banjo is completely missing from the snail/boost reference line!!! So I’ll have to get one from TPS on Monday which means I’ll have to leave it yet another day before I can run it and put coolant in . At least I’ve finally found my infamous leak! I was adamant it was passenger side somewhere.

    I wonder if the car will feel different with it re-connected. Gonna have to ask the mrs to try and get the new one in as my stupid forearms won’t fit, even with the ARB dropped ..




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  5. Samuel c5 Q

    Samuel c5 Q Active Member Silver Supporter

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    You sound like Popeye with those forearms.

    Good work so far. The reservoir is stained by rust from the inside of the engine.

    The power steering pipe looks like it's picking up oil coming from the pan/cover beside it. Is it high pressure side or pump supply/low pressure side?
     
  6. MiniMental

    MiniMental B5 Nut

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    Lol, don’t get me wrong I’m not overly huge. It’s just a very small gap. Haha.

    Yeah I’m gonna replace the reservoir when I drain it out again in a months time. It’s full of gold paste which I’m assuming is radweld from the PO trying to avoid the aux pump leaking. Was well crusty even before it broke.

    It’s high pressure side of the pump mate. New hose isn’t cheap so I hope your right. I’m not losing any steering fluid so hopefully...

    I’m gonna redo all the rocker gaskets, cam caps and tensioner gasket/half moon when I’ve finished collecting the bits for it. Over £200 for them all lol.


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  7. Samuel c5 Q

    Samuel c5 Q Active Member Silver Supporter

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    I could well believe it on the cost of those parts.

    Get a wee kid off the street or your own if you have them to do it.

    If it was a leak on the high pressure side then you would know about it. A leak on the hard pipe or a braid reinforced section comes out at a fair lick. If you do suspect it then you need to observe that section while it is under pressure but mind the eyes and the fingers as it comes out under big pressure. I had a pipe burst with a bag and the hydraulic fluid went all over the engine bay, the floor and up the ramp in the work shop. Pirtek make up pipes at a fraction of the price of OE ones.

    Meant to say as well holts coolant flush is what I used to flush out my system. Put it in and run for a bit then flush out with a hose. Seemed to do the kit for £3 or so.
     
  8. MiniMental

    MiniMental B5 Nut

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    Well, Tuesday was the day of reckoning. I got the two banjos (one spare) I ordered from TPS Monday morning and it took over an hour to fit it. I made all kinds of stupid tools in order to reach. What an absolute ******* of a job. In the end, the mrs did a lot of it as she’s tiny and fits in haha.

    Tool made from a 12” cocktail stick to get washer on back of banjo...
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    All fitted. Never again
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    Couldn’t believe it when I found this missing. Only checked around the area as a fleeting glance for anything obvious. Bang. Banjo missing = 8mm hope in the turbo compressor housing, and likely both wastegates not working due to it being open....

    So, did that, filled with water and bled it all, then Wynns Coolant Flush went in for 15mins. Then drained again and flushed with clean water...

    Then deionised water and G13 mixed 50/50 for now. The amount of **** that come out was mental. Gonna treat it to a new tank this month

    Started nicely, idles smooth as butter. And wow the power it puts down... so so so so happy to say NO BOOST LEAKS!!!! No coolant leaks, and only a cam cap oil leak left to fettle for now. Can finally start on subframes and suspension. Woooo.







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