Subaru conversion start

Discussion in 'Modified Shizzle' started by pkrboo, Mar 27, 2017.

  1. scooby 5 speed conversion is awesome.

    @Baysearcher has had both a VW box and a subarugears box and can advise with actual real world experience of both on whether its worth it or not
  2. coolant problems solved, got a bit yellow snowed off with it tbh so I'll share what I did to fix. This is just what worked for me with a underbelly rad setup. I've got bends and all sorts so it doesn't flow as smoothly as I'd like but its just the way it is.

    Initial very first fill (a year ago now I think) was ok, I had the van jacked up high and did little at a time, over 3 or 4 days it went smoothly but recently I've made some changes to coolant pipes and opened up a load of hassles so hope this helps to avoid my aggro.

    In changing the pipes around I lost a lot of coolant and this led to air locks, I think the crux is theres fluid that doesn't drain and this in turn trapped air after refilling. I really had no idea how severe it might be. I think its called a paradox > adding coolant can overheat your engine.

    First test run I hit 100 + deg quite quickly and blew a lot of coolant but got home ok, some research I realised airlocks but could I get the buggers out!. I tried running warm and squeezing pipes without the cap on, just gently tricking over... don't do that ! air and water expand differently and before you know it..

    I tried jacking the van up real high and leaving for few days but no joy there, the existing fluid was trapping in the locks. I tried running to get it warm hoping air would work its way out + squeezing pipes before it spilled over but no. (just more mess)

    I bought a vacuum kit to suck air out but that didn't work as well as I hoped, just more lost fluid (trust me I learn quickly but this has made me look like a right tit). It did help me confirm my system was airtight though as it held vacuum for 5 mins test.
    In the end I was a bit sceptical but decided to give this a go (short video link, so van on the floor, an empty milk bottle, some duct tape strapped to the top of the expansion.... and it worked !

    Its really satisfying to see big burps of air coming out. Went for a test run and it held 84 and then back down a bit which was a real relief as I'm done jacking my van up and bathing in coolant. Cheap and simple.
    Kingcal, paradox and Lazy Andy like this.
  3. I got this. Same method to your milk bottle
    pgtips likes this.

  4. Does it work through a head of pressure behind the coolant forcing the air out? Defo going to give it a go once the garage is finished as mine has always run a little warm
  5. I think it works by allowing the air (pump pushing fluid > pushing air) to travel around the system until it gets free, or to be a bit more technical. 'burps'.

    Because air expansion is different and quicker to water, trapped air leads to overflow (if the cap is off). Normally the system is closed (pressurised) cap on so, as I found out, that means busting out the pipes.
    I also figure a moving air block will push coolant out/up.
    Last edited: Nov 9, 2018
    StuF likes this.
  6. Razzyh likes this.
  7. Since i rerouted my coolant pipes the radiator fan kicks in a lot more now, at around 82ish, so on at my normal running temps. Before my temp guage would have read above 90 before the fans kicked min.

    Is this normal, what do other people get (when do your underbelly rads kick in?). Mine seem to be on quite a lot when I am up to temperature so obviosuly can't help wondering if theres another problem somewhere needs attention?
  8. That’s strange. Mine comes on at around 95 I think. Only the 1 fan and the other comes on at around 100 I think but it barely ever comes on.

    Mine don’t come on that often.
  9. Dubs

    Dubs Sponsor

    Mine kicks in around 92 from memory, generally only comes on in traffic, or after a motorway blast.
  10. Baysearcher

    Baysearcher [secret moderator]

    My first fan kicks in at about 92-94 ish. Don’t think the 2nd has ever come on.
  11. yes 92 is about what I had before so I need to look into this. Both my fans are hooked up together, I can't recall why but I think it was because I had an earlier loom so obviously its quite noisy.
  12. Fan 1 kicks in at 96 degrees and cuts out at 92

    Fan 2 is something like 105 but I have mine wired on a switch so I can switch it in whenever I want, as I tow.

    All Subaru's are like this.

    If you have an RJES rad pack make sure your fan fuses are 15amp not 10

    @pgtips, doesn't sound quite right to me. What year and model ECU do you have again? Also where is your temp gauge fed from?
    Last edited: Nov 28, 2018
  13. Hi, my Subaru was a legacy 1994/5.
    I've got the temp gauge sender to the dash plumbed in on the LHS hot rad side as it comes into the cross over pipe (just before)
  14. Ah yes early phase 1.

    It could be down to your sender, the ECU should be controlling your fans but the temp gauge runs off the sender you put in doesn't it?
  15. Yes they are seperate, the temp gauge and sender I installed afterwards. So yes fans via ECU.

    You think I need to get ECU looked at?
  16. I would say your gauge and temp sender for the gauge are the more likely culprit.
  17. "I would say your gauge and temp sender for the gauge are the more likely culprit."

    Could you expand on that a bit mate. Are you thinking it isn't reading correct temps and engine is hot?

    It still reads the same normal driving temps as it did before but now my fans seem to kick in more quickly/ more often.
  18. So when your gauge is reading 82 your fans kick in?

    As the fans kick in at 96 I would say that your age is reading wrong. If it is reading low then where you think you are reading 90 it may actually be reading much higher.

    If you have an RJES rad pack ensure you have a good earth to the chassis of the vehicle, do not rely on the earth to the chassis on the rad pack run another wire for earth from there to the earth of the bus.
  19. I'll check the earth. My temps are stable at reading of 80 to 84 (same as always) but now I'm finding the rad kicks in. Knowing the fan kicks in at 96 is useful but it also means I could be running really hot all the time. I have another temp sensor available after the pipe to the heater matrix leaves the cross over so I will get that hooked up as well (runs off PC)
    Thanks pkrboo

    Edit: 5 months later (after winter etc) I finally got out for a proper run to VolksWorld show, round trip of about 120 miles and the temps kept very stable around 82 to 84 with outside temps of say 12 deg so I think its all ok tbh. I kept around 60 to 70mph tops just to play it safe but it was perfect.
    Last edited: Apr 2, 2019

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