sinicl Posted March 26, 2015 Share Posted March 26, 2015 Hi guys, I desperately need help with my golf radiator conversion. For some reason as soon as the car comes up to temp its filling the header tank and boiling over. All the hoses are getting hot and it doesn't appear to have an airlock anywhere. I'm scratching my head to what the problem could be??Using a brand new golf mk2 rad, header tank is from a clio, we put a service valve in the top pipe to work as a reducer, if we have it fully closed then it fills the header tank via the bottom pipe, if we crack it open even a tiny bit it just causes the header tank to fill even quicker. Quote Link to comment Share on other sites More sharing options...
Tim Bancroft Posted March 26, 2015 Share Posted March 26, 2015 Looks very similar to my set up, which has been cribed from Roy Lacey. My only difference is that I do not have a restrictor plumbed into the the top hose going back to the header tank.I seem to be having no issues.Head gasket? Quote Link to comment Share on other sites More sharing options...
sinicl Posted March 26, 2015 Author Share Posted March 26, 2015 Hoping not Tim, its a brand new reconditioned engine! Mind you with some of the issues I have had with the engine builder and his 'work' it wouldn't surprise me. Quote Link to comment Share on other sites More sharing options...
RobPearce Posted March 26, 2015 Share Posted March 26, 2015 How full are you filling the header? I assume that pipe into it comes out near the bottom inside, not near the top, so you'll only be putting in enough to just cover it when cold? Quote Link to comment Share on other sites More sharing options...
sinicl Posted March 26, 2015 Author Share Posted March 26, 2015 Rob, filling the header tank about half full. Just ran it up again, same result. Quote Link to comment Share on other sites More sharing options...
toolmaker Posted March 26, 2015 Share Posted March 26, 2015 have you just done the conversion, was the engine running ok on the old system?so is it definitely the new system? Quote Link to comment Share on other sites More sharing options...
Basil Fawlty Posted March 26, 2015 Share Posted March 26, 2015 I'm no expert on this setup but it sounds like it isnot pressurising properlyThe cap on the expansion bottle should be fully sealed??Baz Quote Link to comment Share on other sites More sharing options...
John Bonnett Posted March 26, 2015 Share Posted March 26, 2015 Your installation is very much the same as I did on my GT6 so I cannot see any problems there. However, I don't understand you saying it boils over. Does this happen through the vented cap? When this happens what does the temperature gauge read? Quote Link to comment Share on other sites More sharing options...
nang Posted March 26, 2015 Share Posted March 26, 2015 Don't understand the need for the restricter valve.Tony. Quote Link to comment Share on other sites More sharing options...
Royboy66 Posted March 26, 2015 Share Posted March 26, 2015 Mine did this when first testing ! It was an air lock, I drained some coolant out then removed the top hose from thermostat housing and filled the rad through the top hose slowly. That worked for me :) Quote Link to comment Share on other sites More sharing options...
sinicl Posted March 26, 2015 Author Share Posted March 26, 2015 Hey guys, thanks for the advice. Laptop battery died so I'm only just able to respond now.As the temp comes up to normal you can see water start flowing through the top pipe back to the header tank filling it. From there it just spikes through the roof. Thinking there could be a number of problems here though. The rad fan isn't really kicking in until its to late. Its got a 95 degree switch in it that was tested and working, going to throw a 90 degree switch in tomorrow and see if that makes a difference. Also thinking I may have an airlock somewhere, all the hoses are getting warm, including the heater hoses, however running the car up without the airbleed at the top of the rad capped off there is only a bit of a trickle that comes and goes in spurts.Was wondering if it was the expansion tank but it makes no difference if we run with or without the cap on, still get the same result. Quote Link to comment Share on other sites More sharing options...
Royboy66 Posted March 26, 2015 Share Posted March 26, 2015 Mine did this when first testing ! It was an air lock, I drained some coolant out then removed the top hose from thermostat housing and filled the rad through the top hose slowly. That worked for me :) Quote Link to comment Share on other sites More sharing options...
nang Posted March 27, 2015 Share Posted March 27, 2015 Another thought, is the thermostat working as it should?Tony. Quote Link to comment Share on other sites More sharing options...
sinicl Posted March 27, 2015 Author Share Posted March 27, 2015 Thermo is working, tested it in a kettle. We're going to pressure bleed it and make sure that its not an airlock. Its got a clio expansion tank which looks to be about half the size of the astra one everyone else uses. I will try and find an astra tank and rule that out as well.Thanks for the help guys, appreciate it!CheersSimon Quote Link to comment Share on other sites More sharing options...
sinicl Posted March 27, 2015 Author Share Posted March 27, 2015 Just out of interest, you guys that have done this conversion, roughly how much coolant do you need to fill the system? Quote Link to comment Share on other sites More sharing options...
John Bonnett Posted March 27, 2015 Share Posted March 27, 2015 The great thing about the MK4 Astra header tank is that because of its shape it fits in as if it were meant to be there and new ones are available for about £25. A level sensor is available too which will give warning before the car starts to overheat. Quote Link to comment Share on other sites More sharing options...
Nick Jones Posted March 27, 2015 Share Posted March 27, 2015 Does your thermostat have an air bleed hole in it? Some don't and as I've discovered to my cost in the past, they can also seal well enough to cause an enormous air lock in the head and because this keep the water away from the 'stat it doesn't get warm enough to open. Meanwhile things are getting far hotter than they should (though maybe not on the gauge as the sensor is also in the air bubble) and water is blowing out of any available orifice obscuring the real problem.You can drill a small hole in it (3 - 4mm) to allow the air through or bleed the system via the temp sender hole.Nick Quote Link to comment Share on other sites More sharing options...
Spit131 Posted March 28, 2015 Share Posted March 28, 2015 Don't forget there is a difference between a catch tank and an expansion tank , both do the same thing .The expansion tank is preasurised but a catch tank can run with no cap .Take it this is an expansion tank ? Quote Link to comment Share on other sites More sharing options...
sinicl Posted March 28, 2015 Author Share Posted March 28, 2015 Iain, thanks for the offer of on the oxalic acid, I'll keep that in mind. I've got an astra tank coming now so I can rule that out. It does look a fair bit bigger than the clio tank.Nick, cheers for the heads up on the thermostat. I'll check it out. Its definitely an expansion tank with pressure cap etc etc.ThanksSimon Quote Link to comment Share on other sites More sharing options...
sinicl Posted April 20, 2015 Author Share Posted April 20, 2015 Just to close this one of for anyone that strikes the same problem. Changed to an Astra tank and the problem went away. Clio header tank was to small.If I get time I may try and measure the difference in volume, be interesting to see how much it was! Quote Link to comment Share on other sites More sharing options...
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