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Heater problem

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  • [Corsa C 2000-2006] Heater problem

    Can anyone help?

    Got a 53 plate Corsa 1.2 SXI and the heater is rubbish. I leave my house at 3:30 am for a 15-20 minute journey to work each day, by the time I get there the heater is Luke warm and temp gauge still on first marker and not 80 degrees which is the next marker. On the way home in the afternoon when the ambient temp outside has increased, the heater does work a lot better but by no means as good as other motors.

    I have put put a new radiator and thermostat on the car and flushed out heater matrix both ways, no sludge or blockage was found. When engine is ticking over as it was this afternoon on 80 degrees, the pipe feeding the matrix from the battery side is very hot to touch but yet the other pipe coming out and connecting to the pump is only slightly warm and possible to hold all day unlike the other pipe. Car works fine in every other way but wish I could get warm of a morning.
    any suggestions?

  • #2
    The usual cause of an engine being slow to warm up is a stuck thermostat, but you've already replaced that.

    If part of the system is getting very hot but the coolant isn't flowing round the whole system you would get this kind of issue. The worrying thing is that if the coolant isn't flowing properly you'll get temperature variance across the engine and they don't tolerate that very well.

    Given that you've replaced the rad and stat I'd be looking for a cause for poor circulation, either a failed water pump (though that usually shows as overheating on the gauge) or an airlock somewhere. The coolant system on them is prone to airlock if it is filled quickly and there's little by way of bleeding them. I find they have to be filled literally at a trickle.

    How hot are the pipes running to the radiator getting?

    Has it always been like this? Just wondering if a previous owner has connected some pipe work up incorrectly.
    1972 Viva restoration thread -


    • #3
      Thanks for your reply Taurus, all pipework is correct and original layout. All pipes get hot, so hot that you can't hold on to them for long. I have taken the small pipe off in the middle of the water pump while the engine is running in order to test the pump, result is a constant fountain of water so pump is ok. I think it's as you suggested, an airlock. After flushing matrix and topping back up with a more diluted antifreeze mix, there seems to be a result. Antifreeze mix was 33% mix, I have diluted to more of a 25% mix which believe it or not actually feels thinner to touch. I have pumped all the pipes to try and elieveate any air locks, the heater is now a lot better but temp gauge is still on cold, it does increase to just over 80 degrees when sat on drive on tick over as I tried today. Hopefully all will be well from now on.


      • #4
        Why have you diluted the antifreeze mix to 25%? Even 33% is pushing your luck. 50% is recommended. You may consider that the -37 degree protection given by 50% is over the top for the uk but you also have to allow for wind chill when first starting off. Although in theory a diluted mix gives slightly better cooling ability you shouldnt need it if everything is working how it should.
        Also have you measured the actual strength using the correct tester for the type of antifreeze in use. Its easy to make a mistake if you have just estimated.

        25% may be ok if you live somewhere that never gets minus temperatures.
        Last edited by Bugman; 26-10-2016, 06:39 AM.


        • #5
          Come up with some useful info Bugman
          Last edited by Clint; 27-10-2016, 12:32 AM.


          • #6
            I keep my garage door open with a cylinder head that was split by frost.Water expands by about 8% when it freezes and its your engine it may wreck,not mine.

            If the air temperature is just 0 degrees windchill makes this minus 10 at 50 mph. At minus 15 (quite possible in the uk) windchill at 70 mph is minus 33.

            Sorry if my post appeared critical. Only trying to stop you making the same expensive mistake many other have made over the years. Maybe 25% is enough,but I wouldnt risk it with winter coming.
            Last edited by Bugman; 27-10-2016, 07:23 AM.


            • #7
              There is also the point that 50% solution is recommended in order to have the correct amount of corrosion inhibitors present over time (coupled with 'quality water' as th manufacturers carefully state)

              I have the heads to prove it.