Bleeding the cooling system
Discussion
Depends how much coolant needs putting in - if the rad has been drained then fill from the swan neck very slowly, squeezing the top and bottom hoses to force the air out. Once you can't get any more in through the swan neck (or if it wasn't drained that much anyway) put the cap back on the swan neck and put a coiple of inches worth in the header tank. Run the engine with the cap off (raising the revs using the linkage on the plenum so you can keep an eye on the water level) until the coolant has almost reached the top of the tank, put the cap on and continue to run until the fan cuts in. Allow to cool and top up the header tank to normal level. IIRC my 350 didn't have an overflow tank, so I just used a conveniently sized plastic bottle to catch the excess, rather than it dumping on the ground.
Rather than remove the swan neck stopper I now take off the hose to the tank at the tank end and raise it high as possible, then use a funnel on that. When the tank level rises you know you've filled it.
When you have no catch tank it's usually better to make one up (sometime there is room next to the header tank) and allow it to overflow in/siphon back. Or else you can get through an awful lot of coolant. An old antifreeze bottle usually works well.
When you have no catch tank it's usually better to make one up (sometime there is room next to the header tank) and allow it to overflow in/siphon back. Or else you can get through an awful lot of coolant. An old antifreeze bottle usually works well.
That's good advice too - and make sure you have the heater control open to burp out that part of the system.
If you do rig up an expansion bottle you could try one of my pressure caps that has a little spring-loaded lid in there. I have a few left and will be selling them off at the fest.
These let air out of the system naturally and will then suck in water when the system cools down, if you leave an inch or so in the expansion tank. However I've noticed that they are quite sensitive to head gasket leaks, where the outgassing will tend to take a fair bit of water with it too (and the bottle will fill up, to be sucked back in later).
If you do rig up an expansion bottle you could try one of my pressure caps that has a little spring-loaded lid in there. I have a few left and will be selling them off at the fest.
These let air out of the system naturally and will then suck in water when the system cools down, if you leave an inch or so in the expansion tank. However I've noticed that they are quite sensitive to head gasket leaks, where the outgassing will tend to take a fair bit of water with it too (and the bottle will fill up, to be sucked back in later).
Edited by adam quantrill on Monday 8th July 08:48
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