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venting air out of water system

Posted: 17 Nov 2013, 17:28
by project25
Hi, I know Ive read it somewhere but cant find it in wiki, but how do you get the air out of the water tank when refilling the system. Ive just replaced the waterpump, not the best of jobs. When all is up to running temp the pressurised bottle is about 3/4 full, expansion bottle in on max.

Re: venting air out of water system

Posted: 17 Nov 2013, 17:34
by CJH
Wait till it's cool, so there's no pressure in the system. Then remove the dalek cap on the pressurised expansion tank (the one on the left side of the engine bay) and top it up. The next time it gets up to temperature and pressurises any remaining air should be vented out to the overflow (top-up) tank. When it cools down again it will draw coolant back from the top-up tank.

Re: venting air out of water system

Posted: 17 Nov 2013, 17:40
by project25
Hi, thanks for that I was hopping it would be something simples, as its gone dark out I was going to try that tomorrow morning. I did here stories of having to lift the front of the van up and venting out the rad!

Re: venting air out of water system

Posted: 17 Nov 2013, 17:42
by CJH
project25 wrote:Hi, thanks for that I was hopping it would be something simples, as its gone dark out I was going to try that tomorrow morning. I did here stories of having to lift the front of the van up and venting out the rad!

Ah well, yes, if you've drained a significant amount of coolant, which you will have done by changing the water pump, then you should follow the advice in the wiki to bleed the system fully. The advice I posted above was simply for filling the expansion tank.

Re: venting air out of water system

Posted: 17 Nov 2013, 17:51
by project25
Thanks for wiki link that was what I was trying to find. I only drained out a few litres when I did the pump so maybe I'll get away with just topping up the pressure bottle.

Re: venting air out of water system

Posted: 17 Nov 2013, 17:57
by CJH
project25 wrote:Thanks for wiki link that was what I was trying to find. I only drained out a few litres when I did the pump so maybe I'll get away with just topping up the pressure bottle.

I wouldn't bank on it. It's not a difficult procedure - undo the clips on the front grill so that you can get to the radiator bleed screw (top left), run it up to temperature with the heater set to hot, and then just keep revving it, topping up the expansion tank, bleeding the radiator, revving it, topping up the expansion tank........ Note the important bit that it's best to top up the expansion tank while you're revving the engine, since the water level will rise back up when you drop the revs.

Re: venting air out of water system

Posted: 17 Nov 2013, 18:19
by project25
Looks like I'ii be working in the dark and cold (looking at weather forecast) cos I dont get back from work until 5.30. I suppose you dont need too much light to do the bleedin job !. Thanks for info though.