Hi
I have a problem (maybe). I thought it must be about time to change the coolant on my golf - not sure when/if it was last done.
Anyhow, so I drained it all out and flushed out the radiator. I haven't flushed the engine as apparently I'd need to remove the thermostat which as a novice I didn't fancy doing. Reconnected all hoses and started to refil. For some reason, despite about 6 litres coolant coming out when I emptied it, I can only get 2 litres back in?! I assumed an airlock and have run the engine up to operating temperature with the expansion cap off (the radiator started steaming and the cooling fan kicked in)but hasn't seemed to clear it?
What do I do? I need to get more coolant in but I can't. How do I know the thermostat is definately working?
Any advice much appreciated/
Jimothy
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How do I know the thermostat is definately working?
If it's working (as in opening when hot), then the pipe leading back to the top of the radiator should be warm.
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Possible airlock in the heater;put heater to full hot;top up the system and put the filler cap on;start the engine and let it warm up for several minutes;then take the engine upto about 4000 rpm for about two minutes,alternatively slacken the clip on the top heater hose near the heater when the system is under pressure;you don't want the hose coming off;be careful of the hot water-it can spray a long way.You need to run the engine fast so that the pump puts sufficient depression on the heater matrix to suck out the air-it won't do it at idle.
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OK - thanks for the tips.
All the pipes to / from radiator get hot so I guess the thermostat is ok. I ran the engine with heater on full wack and at 4000rpm for a few minutes - and got very hot! No problems there. The engine still gets to about 105C at idle before cooling fan cuts in - but it was doing that before I changed the coolant.
My big concern is that despite everything is running 'normally', I've definately only added just over 2 liters of coolant / water and I'm sure it needs about 6 and a half...? Assuming it all emptied in the first place? The new coolant is pink and the old stuff was a blacky/bluey/green and certainly the stuff in the expansion tank is all of the pink variety.
Any more thoughts? I don't want to take the car out and have it overheat 30 miles from home...
Cheers
Jimothy
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A lot of the older VW's had a bleeding point high up on the plenum chamber. The thing with any cooling system is to fill it very slowly, that way you prevent airlocks developing. Try loosening the bleeding valve and blowing into the expansion tank. Any air should come out.
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OK - where abouts is this (I am not, unfortunely, too mechanical). Can't see any details on this in the Haynes manual...?
Cheers
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Used to be on top of the cabin blower on older VW's. Haynes manual should tell you all though.
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Did you measure the water when you drained it out?Even a pint looks an awful lot on the ground.
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I didn't measure it but it was at least four inches in a washing up bowl that came out. The Haynes manual says it needs about 6 litres. I dunno - maybe it is ok, but seems weird. I'm going to take the car out and see what happens....
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Used to be on top of the cabin blower on older VW's. Haynes manual should tell you all though.
OK - I see no evidence of any bleed valve. Will the airlock clear itself or am I going to have a roadside incident some time soon if I just run the car?
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THe Haynes manual should tell you the correct procedure for filling the system. If you follow it carefully, I can't see you will have a problem, as long as you set the cabin heater controls to hot so water can enter the heater matrix.
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You never get all the coolant out when you drain,there will be some left in the engine block for example.The average w/u bowl is 8-10 litres so 4" does not sound like 6 litres to me.Check the top hose in particular and the ones running to the heater,if the hoses are hot they have coolant in them and all is well.
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P.S.usually the worst that will happen with an airlock is your heater blows cold.
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OK - well I've definately got hot air from the heater. I'll just keep an eye on it over the next few days. Thanks for the tips everyone!
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