Strange coolant leak - any ideas?

Discussion in 'Technical' started by taszed, Oct 9, 2008.

  1. taszed

    taszed New Member

    Hi Zedders,

    I have a problem and hopefully you guys can brainstorm a few ideas...

    I have a strange coolant leak... I'll try to explain how I found it...

    About 2 months ago I noticed my coolant level was just a touch low so I did Tekkies coke bottle method of refilling and removing air bubbles and that went well. Car ran fine and I *think* that there have been no probs up until nowish.

    A couple of days ago I got home form work (15-20 min drive, just cruising) and parked the z in the carport. 20 mins later I go for a 2 min drive to the shops and when I get back I notice a small puddle of coolant, maybe 100ml or so. I park the car there and sit a catch tray under it and NOTHING. not a drop since then. It's as if it just 'dumped' a bit of coolant and thats it. Looking in the rad cap the level is now a bit low but I can still see it.

    Also worth noting I noticed a similar sized coolant puddle maybe 1 month ago on the lawn where the z had been but assumed that it was from another car because again there was no dripping coolant from the Z and a mates car had been there as well.

    Except for these two instances I haven't noticed any other issues! and I had a poke under the bonnet and couldnt immediately notice any leaky hoses (but I'm a newb so that means nothing).

    Going to take it to mechanic but was hoping for a few thoughts/suggestions to take there!

    Thanks guys!!
  2. K-zed

    K-zed Secret Squirrel

    What does coolant level show on expansion tank dipstick with cold engine?
  3. AndyMac

    AndyMac Better than you

    Check your expansion tank it may be overfull, causing it to leak out the top when the pressure increases and the cooling system dumps some water in the tank. Also where about's is the puddle in relation to the engine. Front passanger side wheel area, in the middle near the gearbox, etc.

    Also keep in mind, that once the water pump stops turning and the coolant in the block, turbo's, and pipes round the back start to soak up heat, the pressure increases quite a bit and will often find leaks that other wise wouldn't appear. THey're generally a precursor to something more serious.

  4. taszed

    taszed New Member

    Right. The puddle seems to be in the middle near the front of the gearbox I think. And I'm slightly embarassed to ask this (see aforementioned newbness) but where do I check the expansion tank?? Sorry... And thanks!!
  5. wooly1953

    wooly1953 (EDSZX )

    expansion tank

    the cap is on the passenger side front under bonnet(green plastic)
    have a look in teck section excellent article under cooling:zlove:
  6. mafi-zed

    mafi-zed the resident hoon

    so, its on the right near the gear box?

    the gearbox is located in the middle, and at the very back of the engine..

    can you get a little more specific please
  7. taszed

    taszed New Member

    Sorry mate I meant it looked to be dead centre at the back of the engine. I.e. near where the gearbox bolts up to the engine.
  8. K-zed

    K-zed Secret Squirrel

    You sure it's coolant?

    And not air-con evaporator water? Is it clear or coolant-coloured?

  9. taszed

    taszed New Member

    definitely bright green coolant. Im thinking about biting the bullet and getting the full 100k service done but that won't generally involve replacing coolant lines right? Was also thinking of doing plenum pull at the same time and bypassing all the under plenum water hoses. The general consensus is that this is safe to do in oz climate isn't it? Any idea on the cost of getting all that work done by a mechanic?
  10. Benny_C

    Benny_C About as subtle as...

    sounds more like...

    heater core hoses or even turbo coolant lines which are at the rear of the engine. If it looks like its coming from there, i'd try to locate it a bit more to try to find out which actual hose it's coming from. And if you're up to doing a plenum pull, i'd do the bypass while it's off. Better safe than sorry, and it's easier while the plenums off too.
  11. jaybo

    jaybo New Member

    definitely see if you can gauge where its coming from.
    i did a plenum pull last year and didn't replace my heater hoses.
    once the car was back up and running a couple of times it leaked, but there was no consistency with it. as i drove the car more and went for longer drives it then got really bad - was stuffed heater hoses.

    so replaced the two of them - was able to do it with the plenum on but mine is an NA, still had the EGR there as well.
  12. OdinZ

    OdinZ New Member

    yeah it sounds alot like the heater core hoses. to check these... they are two black hoses at the top behind the engine which run in and out of the firewall between the cabin and the engine bay. could be a crack in the hose or leak around the hose clamps. check under these hoses for any signs (ie. staining) of leakage.
    if this is it u can pick up the hoses cheap from repco. i think there is a tech article with the part numbers somewhere.
  13. Fleet

    Fleet Speed Racer

    if the leak is from the rear of the engine then a coolant system pressure test should reveal where its coming from.
  14. zed4life (

    zed4life ( Ω vicarious zedder Ω


    What Benny said ...:)

  15. taszed

    taszed New Member

    Thanks for all of your advice guys! I'll have a good look for the leak this weekend and will probably go to my mechanic with your suggestions and talk over the options. Will most likely end with a 100k service and plenum pull ($$$:eek:)but hopefully once that is done I should be right to relax and enjoy the car without worrying about it! Just gotta replace that noisy thrust bearing now... :rolleyes2: :zlove:
  16. pexzed

    pexzed Forum Administrator

    This is going to sound silly, but I had a similar problem about 2 months ago.

    I pulled up at my destination in the Z, and when I got out of the car I got the coolant smell and the car dumped about 200ml of coolant (green) on the ground. It came from the back of the engine
    I left it for about 30 minutes, not a drop more came out. I filled the radiator, ran the engine for 20 minutes, not a drop more came out. I rang Pete at AMEC, and took a chance and drove there (20 minutes), and kept a close eye on the temp gauges.
    Got to AMEC, and stopped engine, no more leaks. Hmm very strange.
    Then we pressurised the cooling system with the pump, and bam, coolant pissing out of a heater hose at the back of the engine.

    Now, this is what happened

    One of the heater hoses had a 3 inch long split in it, but, since the hose was wrapped in a rubber protective sleeve, that was enough to keep water in the system until the pressure exceeded what the sleeve could hold in.

    When the pressure exceeded this point (like under heat soak), coolant would leak fast and then disappear making it hard to find.

    This might be worth investigation in your case too.
  17. taszed

    taszed New Member

    Thanks Greg,

    That sounds a lot like my problem as it has only happened twice (I think) in quite a few drives, and only after the engine is shutdown (heatsoak). I think I'll chance a run to my mech (15 mins away) to get the system pressure tested as Pete suggested and I reckon I'll find a similar problem to yours. I'm hoping for an easy heater hose replacement fingers crossed!!

    Once again thanks very much for taking the time to help me out, I am very appreciative! :zlove:

    EDIT: P.S. Tasmania is a fantastic place to raise a family etc, ideal Z weather (not too hot but warm enough for targas off!) so I think that Pete and a few others should consider setting up shop down here!! Pretty please?? I'll shout an airfare...
    Last edited: Oct 10, 2008

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