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How to bleed the coolant system the easy way

Discussion in 'All Model Vauxhall / Opel / GM / Holden How2' started by M32Guy, Feb 23, 2016.

  1. M32Guy

    M32Guy M32 Specialist

    Messages:
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    Location:
    Scotland
    Drives:
    Astra H VXR Arctic Corsa C 1.4 Auto
    This was written for a Z18xer engine but the same applies to all petrol 'Z series' Vauxhall engines (from about 2000 onwards) and will also apply to the newer 'A series' engines too.

    Full the tank up to maximum line with your coolant mix and squeeze this radiator hose a few times
    image.jpeg
    image.jpeg
    Let whatever coolant wants to bubble down into the system do it's thing while keeping an eye on the level. Try not to let it get too low below the minimum line. When it stops, refill to the max and repeat. Keep doing this until your squeezing the bottom hose and it feels full. It will feel different when it's full of coolant instead of air. It's important to ensure the pipe is full as this indicates the radiator is also full and it will save a lot of time and effort later on. Fill the tank up to about 3/4 of an inch above the max line and put the cap on fully
    image.jpeg
    The level here is exactly on the maximum. At this point in time you want it roughly 3/4 of the way up between this and the ridge line above.

    Start the car, turn the heaters to full heat and the put the fan setting to 1. Let the car idle for a few mins before taking the revs upto 2500. Keep an eye on the temp gauge if your car has one. If not, its advised to use a diagnostic computer such as op-com to keep an eye on the coolant temprature. The heaters should start to get warm after a couple minutes of the fast idle, it's important to keep the fan speed at 1 or it will take a lot longer to bleed the system. Make sure to keep an eye on the coolant level every couple minutes.

    If it drops below the minimum stop what your doing and let the engine cool before removing the coolant cap. If you don't, you risk hot coolant rushing out and air rushing in. Remember we're trying to remove all the air and not get burnt! When the engine is cool (about 30-40 mins) top it back up to the same level above the max line as before. This is why it's important to spend a little time to fill the radiator up so you can miss this step out.

    When the temp gauge gets half way or the coolant temp shows 90C check the coolant level again. It should be just above the max and the heaters should also feel quite hot by now. Feel the radiator hose you were squeezing earlier. The thermostat should be open by now so the hose will be very hot to touch so be careful. If not re check every minute or so until you are sure the thermostat has opened. There will be a big difference in the temprature of the pipe when it does.

    Keep the fast idle going until the fan cuts in but don't let the temp gauge rise past two thirds or 120C. The fan should cut in after 10-15mins of the fast idle at about 110C. When it does, let the car idle until the fan cuts out and back in again. When the fan turns off for the second time switch the engine off and check the coolant level again. It should be right around the max line if not slightly above. DO NOT open the cap for any reason at this point. Not only will you risk getting burnt by the coolant you will also let it suck in air as the system depressurises. Let the engine cool for at least 40mins (preferably an hour or ideally overnight) and recheck the level, it may of dropped slightly from where it was. Top up if required. If you haven't already left the car overnight, check the level again in the morning as it will of dropped slightly. Remember you want it to look like this when done.
    image.jpeg
     
    Last edited: Feb 25, 2016
  2. Jamesb1987

    Jamesb1987 Well-Known Member

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    Location:
    Fife Scotland
    Drives:
    astra coupe g 2.2
    I opened a car with suspected head gasket problem before, who would have known, pressurised boiling water and steam really hurts. Lol
     

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