Air in coolant

Post by **ozzy** » 27 Apr 2006, 10:32

I have just tested the cooland res with one of those sniffer kits and the air in my res tested negative for co2.
So it aint a cracked head. Ill run the symptoms by you again.
1 Loads of air getting in the coolant
2 No water loss ive had the whole of the van sitting on carboard for a week
3 bubbles can be see returning to the res tank when engine is running
4 checked all hoses and cant see any leaks
5 put block crack stuff in coolant to seal any small holes just in case
What next ?? waterpump? im lost now cant think of anything else

Post by **Horza** » 27 Apr 2006, 11:00

5 put block crack stuff in coolant to seal any small holes just in case

Isn't that what your supposed not to do?

Simple physics sais the air was already there or it's getting in somewhere. No chance there is water forming an interesting puddle somewhere? On top of the fuel tank? Somewhere in the front? What about dripping on something warm enough to evaporate it? I take it your have now bled the blinking thing more tan once with it's nose in the air as per the Wiki? Do you have one of those rear heater matrixes? Is it wet under the bed? What about in the cab footwells?

Post by **Louey** » 27 Apr 2006, 11:01

ozzy wrote: 5 put block crack stuff in coolant to seal any small holes just in case

not meant to be a good idea

can't think what else to do except bleed the sod again

Post by **Ray** » 27 Apr 2006, 11:29

Is it the pressure cap? I had similar, if the system is not presurised it could be steam rather than air. I changed the blue cap and was cured.

Post by **ozzy** » 27 Apr 2006, 15:30

The cap should be ok as the pressure builds up and when air gets into the system the water displaces into the top up tank sometimes rising right up to the filler cap.
As for putting block sealer in that was a "pooh" or bust move and this stuff was recomended by a vw specialist garage that does most of its trade through bays n t25s.
As for damp patches as i have said it aint loosing water, in the last 18 months i have not topped the coolant up just have to keep bleeding the air out.

Post by **Horza** » 27 Apr 2006, 15:39

Gah, doesn't sound possible, the system is under pressure which should stop anything getting in anywhere,air or not unless what is getting in is under more pressure as in exhaust gasses. I suppose if the system is pressurised when hot and some air bleeds out, then it cools forming low pressure it might be sucking some in somewhere but it's going to be a pig to find.

Post by **ozzy** » 27 Apr 2006, 15:59

Thats what i think and yes its gonna be a pig ive booked it into volkstop on the 9th may see what they can find

Post by **Ivor Brownun** » 28 Apr 2006, 23:42

Any joy yet? be interested to find out how you get on with this. I'm not any good with anything technical but could this be the same air in the system ? i.e you think you've bled it out but its been "hiding" in the system somewhere, only to reappear after you've driven around a bit and "dislodged " it. Remember I did say I'm not technically minded

Post by **ozzy** » 30 Apr 2006, 19:30

If it is the same air then ive had enough air to blow up a bouncy castle

Post by **Ivor Brownun** » 01 May 2006, 21:49

Post by **Ivor Brownun** » 04 May 2006, 21:22

Any joy yet?

Post by **NeedABus** » 05 May 2006, 07:37

I had a similar thing - found a small split in a hose. Fixed that and found a small leak in the radiator. Replaced that, noticed when pressurised the radiator cap was letting steam out.

Then the head gasket failed catastrophically!!!!

Aiming to get it back together this weekend, and I'm also going to put on a new expansion tank and cap.

Hope yours isn't so serious (although to be honest I am quite enjoying doing the gasket myself - only way to learn!!!)

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Air in coolant

Air in coolant

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