Changing and bleeding coolant
Discussion
Just wondering if I can't find the drain plug on radiator, can I just disconnect any of the hoses going to the bottom of the radiator? And also I've been watching people bleeding their coolant to get air out of system on youtube, can't you just take of the reservoir tank or radiator cap of and wait for coolant to stop burping whilst topping up if it goes below min? The car is a 1.9 golf tdi mk4
Thanks
gawri.
Thanks
gawri.
Before you switch off the engine, set the heater to maximum temp and put the heater fan on.
To drain, disconnect the large hose going to the bottom of the radiator. There will also be a drain plug on the engine block somewhere, this is well worth using as you won't get all the coolant out otherwise, and often the worst of the sludge is in the engine block. Loosen any bleed screws and remove the header tank cap to ease draining and bleeding.
Find out how much coolant the car is supposed to take and have the right quantity to hand. Slowly pour it into the header tank, not allowing the level to go over the 'max' mark. Once you can't get any more in, and provided you have managed to put in most of the guide quantity, put the tank cap on, start the engine, hold it at fast idle and tighten the bleed screw when coolant starts gushing out. Check the heater is blowing hot and allow the engine to run fully up to temp until the radiator can cuts in. Keep an eye on coolant level throughout.
Once the engine is cool, do a final coolant level check and the job's a good 'un.
The tank cap needs to be on when the engine is running because the system operates under pressure and with no pressure the coolant can't displace the air if pockets have formed.
To drain, disconnect the large hose going to the bottom of the radiator. There will also be a drain plug on the engine block somewhere, this is well worth using as you won't get all the coolant out otherwise, and often the worst of the sludge is in the engine block. Loosen any bleed screws and remove the header tank cap to ease draining and bleeding.
Find out how much coolant the car is supposed to take and have the right quantity to hand. Slowly pour it into the header tank, not allowing the level to go over the 'max' mark. Once you can't get any more in, and provided you have managed to put in most of the guide quantity, put the tank cap on, start the engine, hold it at fast idle and tighten the bleed screw when coolant starts gushing out. Check the heater is blowing hot and allow the engine to run fully up to temp until the radiator can cuts in. Keep an eye on coolant level throughout.
Once the engine is cool, do a final coolant level check and the job's a good 'un.
The tank cap needs to be on when the engine is running because the system operates under pressure and with no pressure the coolant can't displace the air if pockets have formed.
Westfield and Caterham do a bleed T
You cut this in to a 16mm hose at the highest point, usually a heater hose, fill from header tank or top of radiator if coolant does not bubble out of the open bleed T top up through the bleed T until it does.
I use this method on my 7 as it has no header tank (yet) and fills to the radiator which is low in the nose.
You cut this in to a 16mm hose at the highest point, usually a heater hose, fill from header tank or top of radiator if coolant does not bubble out of the open bleed T top up through the bleed T until it does.
I use this method on my 7 as it has no header tank (yet) and fills to the radiator which is low in the nose.
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