88 GTI 8v first start after 10 years any advice welcome

Discussion in '8-valve' started by GTIBOB, Jul 14, 2020.

  1. H8V

    h8v Forum Member

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    The mod done by VW had one of those alloy valves on each heater hose, joined by a small rubber pipe. I can only see one alloy valve on yours. Anyway, it's probably best to revert back to a straight connections to give a good flow.

    As luck would have it my matrix split a couple of weeks ago. I wasn't driving but the car had been sitting in traffic and overheating. Despite the coolant filler cap having a release pressure of 1.5 bar, the matrix burst. A bit of a mess, and anti freeze doesn't evaporate away! You can see the crack all along the top in one of the pics. The cause has been resolved; the rad fan cables have a plug and socket connection behind the n/s headlight and it had rotted away. I've now replaced the rad fan cables with ones straight to the battery, with soldered ring connections as a more lasting arrangement.

    Out of curiosity I dismantled the matrix. Here are some pics. The coolant flows in to one side of the plastic cap, down the alloy pipes, then back up to the other side of the cap and out of the return hose. The cap sits on a rubber seal all around the pipe ends and has a divider along between the flow and return pipe ends so I don't see there is chance for any coolant to avoid going around the alloy tubes. If you were getting a good flow both ways when flushing and you say a lot of muck came out, then I reckon the matrix should still be functioning OK.

    Try removing the valves in the flow and return pipes and see if that helps. I can't see any reason for the hot coolant to not flow through correctly. You will need to rev the engine a bit to get the coolant to begin to flow uphill through the hoses, but once it's started it should be OK.
     

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  2. rubjonny

    rubjonny Administrator Staff Member Admin

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    the way the matrix are made means even if you get flow thru, doesnt mean the unit itself is still clogged. as long as at least one of the core pipes has flow water will get thru it, even if all the rest are shot
     
  3. rubjonny

    rubjonny Administrator Staff Member Admin

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    the matrix above is actually inferior design to original OEM, as those have plastic inserts pushed down the cores to force the water to move around more transferring more heat. the downside is they clog more easily, and when they fail you end up with chunks of 'curly pasta' in the coolant tank
    matrix1.jpg
     
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  4. H8V

    h8v Forum Member

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    (It was a Nissens 73961. In a nice box, but no markings on the actual unit!)

    Sorry, the new one is a Nissens. That old one was only about 10 years old and from either GSF or ECP/ CP4l I think.

    Final edit... the old one was from Euro Car Parts. £21.30 New Nissens £20.88
     
    Last edited: Apr 19, 2021
  5. GTIBOB

    GTIBOB Paid Member Paid Member

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    Many thanks for advice and details Re. Matrix
    I’ll try removing the bypass mod with two straight joints to see if I can get stronger flow through matrix.
    If I got flow through matrix in both directions with garden hose flush does that mean matrix is definitely not blocked? Can coolant pass through the top of matrix without passing through the main radiator part?
    Definitely have flow in and out of both matrix hoses
     
  6. rubjonny

    rubjonny Administrator Staff Member Admin

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    water coming thru doesnt really tell you anything, can see all the cores are in parallel so you could have 2 free flowing but the rest clogged for example. this is thy flushing doesnt get you very far, at least with a radiator you can take it off and shake about
     
  7. H8V

    h8v Forum Member

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    (writen before RJ's comment above and posted after!)

    If there is good flow both ways when flushing through the matrix then at least some of the tubes are flowing, though as RJ says, it's no guarantee that all are fully clear. If you look at my first two pics, you can see the divider moulded across the centre of the plastic cap, separating the 'in' and 'out' ends of the tubes and the sheet of rubber to seal things, so it seems impossible for coolant to avoid being compelled to flow through the matrix tubes.

    Just a thought...disconnect both matrix hoses, hold them up as far as poss. blow through one to clear out most of the coolant then use a funnel to pour boiling water in one hose till it comes out of the other. Then see if some of that heat shows up in the car air vents when the fan is on.
     
  8. rubjonny

    rubjonny Administrator Staff Member Admin

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    even that test wont tell you all that much, if you leave it sat with boiling water in you'll eventually get heat soak across it but when driving along with cold air blasting thru it that'll soon get wisked away
     
  9. rubjonny

    rubjonny Administrator Staff Member Admin

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    not trying to be the bearer of bad news though, may just be the valves :lol:
    if the matrix has never been done to your knowledge though, its best to just do it. you could have done it by the time you've spent posting on here about it ;)
     
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  10. GTIBOB

    GTIBOB Paid Member Paid Member

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    Been quiet for a bit
    Have put off replacing the matrix until after the summer as just enjoying driving the GTI again after 20 years of storage.
    Have now done around 800 miles since putting back on the road in April. Took it on first long test run of 120 miles each way which involved about 50 miles of motorway. Kept an eye on the coolant and temp gauge stayed around middle for entire journey so touch wood car can now be deemed reliable.
    But not all good as on way home in city driving it became difficult to select first gear at traffic lights and slow driving.
    One thing I haven’t done is either checked or renewed the gearbox oil and I’m guessing it’s never been done since new. Could this be causing a stiff first gear?
    Replaced all of the gear linkage bushes except for the difficult orange ones which didn’t seem to have too much play.
    Any thoughts on the sticky first gear short of fitting a replacement gearbox???
    All other gears perfect
     
  11. watercooled Forum Member

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    Not likely the oil unless its like mud ,you need to change all the bushes,have you done the shifter box ones ? when you rebush every other part the shifting will be great but any left will become the weak point or points in the system.
    Also the position of the first relay arm from the shift rod needs to be fine tuned for best shifting,it adjusts back and forwards and around on the spline and should be setup in neutral from memory it has a real impact on shifting if not right ,I used to clamp the rod with the car in neutral and set from there,however there will be a link on here somewhere.
    My last hybrid engine conversion using 020 box consisted of rose jointed relay rods and altered
    shift arm...like a hot knife into butter.
    Impressed with what you have done and what you have learned...great job man,top marks.
     
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  12. rubjonny

    rubjonny Administrator Staff Member Admin

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    did you also do the plastic gearstick bush housing on the bottom of the shifter housing? grab the stick and lift it upwards, if theres play it wants doing. Having said that its normal for 1st to be tricky to select unless you're almost at a complete stand still just seems to be something they do. but tbh 2nd is so short you dont really need first unless you've stopped anyway.

    another thing thats worth looking at is the quality of the bush kit you fitted, if poor you may find the bushes go soft when they get very hot. try hotgolf on here aka gas n gears who does a nice metal upgrade kit for the rods and iirc does nice high quality solid bushings as well. If not you can get a kit of those from missinglinkz in the states, dont forget to order the one which replaces the orange bush you mentioned as that one gets the most beating from the exhaust

    gearbox oil is dirt cheap from VW so no point messing about, need 2 bottles of G 060726A2 at 8.35+VAT
     
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  13. GTIBOB

    GTIBOB Paid Member Paid Member

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    Cheers WC i know I’ll probably have to have a closer look ans as you say perhaps adjust the spline clamp. Been lazy and just done the easy engine bay linkage bushes and really must now do the shift rod orange bushes and the stick ball/cup.
    Can always start off in second in meantime
    Cheers for your comments
     
  14. GTIBOB

    GTIBOB Paid Member Paid Member

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    Cheers RJ I know I should do the orange and ball housing bushes but just enjoying driving the GTI again after so long off the road. Will have more time in couple of weeks to get all bushes and the heater matrix replaced
    Thanks for your comments and information as always
     
  15. GTIBOB

    GTIBOB Paid Member Paid Member

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    Just checking in as have been inactive for a while
    Thanks to all the advice and encouragement on here the Mk2 is still going strong since I finally got her back on the road back in April.
    Was a bit nervous at first and reluctant to Rev hard for fear of something blowing or breaking, after all the car had been off the road for 21 years. I took the car on a 200 mile round trip to test endurance on motorways and it never missed a beat. So I now have confidence she won’t let me down.
    Still a few jobs like heater matrix to do but that will be a winter task.
    Really enjoying the car and the attention it gets. Even Golf R drivers have flashed in appreciation I presume.
    Now that I’ve done about 2k I have more confidence in reving a bit harder in 3rd and 4th and am beginning to notice a bit of torque steer so there is definitely a bit of power there and great torque in 5th for overtaking.
    Great not to have to worry about abs or engine management lights just well built and simple engineering. Using 97+ octane fuel makes a difference and adds a few pops on overruns.
    Hope others persevere with their projects to keep these great classics on the road.
     
  16. GVK

    GVK Paid Member Paid Member

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    Great update, enjoy the mk2 as a classic
     

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