• Hi all. I've been floating around on the Facebook group for a while now and I though it was time to start a build thread and properly introduce myself.

    I've wanted a z11 for ages, ever since I saw a lowered metallic green one in bath years ago, and when one popped up on eBay I couldn't resist and snapped it up for 700 quid. 83k miles, full service and maintenance history and slightly tatty paint.

    There was obviously a catch. An overheating problem I'm sure a few of you are familiar with. Combustion gases in the coolant blah blah. The problem got a lot better after a couple of bottles of steel seal and I barely notice it now, however my plan is to do the k12 engine swap before any major mods, but once that's done I'll hopefully be down low and sitting sweet in time for next season.

    This is a great club and I look forward to many years of cube ownership. I'll be documenting the engine swap and all the mods here. Any help would be greatly appreciated and I'll be happy to answer any of your questions.

    A pic I took when I first got her (the flower is gone now)
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  • Flower off, lego brick in, sub and head unit in, at her first meet hiding in the corner :)
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  • After another overheating incident I found that the bottom radiator hose was much cooler than the other hoses, I took her into the shop and removed the thermostat. This is a job id definitely recommend doing. It looks like the plastic thermostat housing can hold the round rubber seal in there on its own too :) overheating has more or less stopped for now. Although I'm yet to take her for a 'proper' drive. Fingers crossed
  • Hi

    So you've removed the thermostat completely?

    Won't that lead onto other overheating issues?

    Let us know how it goes.

    Thanks
    Phil


  • I can't imagine why it would tbh. All the thermostat really does is keep the coolant in the engine until it reaches operating temperature, after which it opens and directs flow into the radiator, interior heaters etc.

    I have noticed she takes longer to warm up now, but that's not such a big deal. I'm just happy to be able to go longer than a few miles before getting the red light of death. We'll see how it goes
  • Ah fair enough then, wasn't sure if it controlled the radiator fan too or are there separate thermostats?
  • I would expect that the bottom radiator hose would normally be cooler than the top. That is the radiator doing its job of removing heat. Taking the thermostat out completely is not a good idea in general. The engine will be running too cool, which is no good for fuel economy, and the heater will not work too good either. Did you check if the thermostat was opening OK?  You can put it in a pan of boiling water to confirm.
    If you leave the thermostat out it will eventually warm up on a long run, and overheat anyway; If you are losing water into the engine due to a faulty head gasket.

  • It's more of a temporary solution. Combustion gases are getting into the cooling system and eventually causing it all to shoot out the top of the expansion tank. She passed emissions on mot and no funny smoke out the back
  • OK, it does sound like it needs a head gasket then.
  • Overheated again tonight on a 1 hour drive back from the skatepark. Pulled over and put about 3 litres of water in. The problem is better but by no means fixed.

    Now I can't decide wether to do the head gasket, or just drop a k12 engine in and be done with it. Insurance runs out on February so I'll be putting it in a garage and won't roll out again until it's finished
  • If it has service history like you mentioned, then chances are the engine is in OK condition except for the head gasket. The engine you swap in might not be as good.
  • It's cheaper too, I'll probably do that
  • Been running around with no thermostat for a while now. In the cold weather she takes forever to reach operating temperature and I think fuel economy has been affected too.