Another problem - water level down

Wed Oct 29, 2008 5:09 pm

Sorry to be back with another one.

I checked the water level in my expansion tank at the weekend and again today. I've hardly used the car but it seems to be down an inch or so. The car has not been overheating and I can't find a leak.

What would be the first thing for me to do?

Wed Oct 29, 2008 6:23 pm

just top it up, keep an eye on it and carry a couple of litres in the boot just as a precaution.

Keep an eye on it over a few days and report back. Make the obvious cursory check of the oil filler cap to check for mayo and also dipstick. This will help to rule out oil & water mixing signaling headgasket/head problems. Also, although difficult at this time of year, but keep an eye out for steam coming out the exhaust, I mean quite a bit not the normal amount you'd maybe expect on a cold morning whilst the car is warming up.

See if you can park the car up on a surface which would show up any water dropping onto it and also maybe make a check under the bonnet when it is warmed up with as sheet of brown paper, hold this near pipes and the radiator etc. Sometimes, there may be minute pin sized holes in pipes or the radiator and the jet of water they release is so fine it can't always be seen.

Wed Oct 29, 2008 6:41 pm

Thanks beemerlad. Will get on the case tomorrow.

Wed Oct 29, 2008 8:48 pm

Don't be absolutely anal about keeping the level exactly on the mark. An inch down won't affect the cooling in the slightest - just keep an eye on it and make sure it doesn't continue to fall.
My wife's car (RIP) (car, not wife), always ran with the level about 15mm low, and would immediately push out any extra added to bring it up to the 'correct' level.

Wed Oct 29, 2008 9:06 pm

Thanks Brian, always reassuring to hear your words..

Wed Dec 24, 2008 10:01 pm

my 325i takes about a week to drop so low you cant see the level!
but no signs of mixing.....or over heating

a lot of it seems to be coming out the exhaust as condensation...what does this mean?

any helpfull ideas thanks

Wed Dec 24, 2008 10:14 pm

Mine steams a lot this time of year too and it's not using water.

Have a look under the oil cap for the dreaded mayo, then pull the plugs out and compare the colours of the tips, if water is getting into 1 cylinder then that plug will appear clean (usually) depending on the amount of water getting in.

If your absolutly sure that there is no leek in the cooling system then the engine must be using it... Hopefully it will be a headgasket.

Wed Dec 24, 2008 10:30 pm

now then donny lad!

i will check my plugs but definatly no mayo under cap.a compresion test would give me peice of mind and it can have a new gasket at same time

Wed Dec 24, 2008 11:00 pm

burgoil wrote:a lot of it seems to be coming out the exhaust as condensation...what does this mean?

It means you're burning petrol! A little extra from the cooling system wouldn't be noticeable amongst the water produced by combustion.
Don't be too sure you don't have an external water leak - they can be almost impossible to find sometimes.
Water pump, only when the engine running is a favourite, could be a pinhole leak from the radiator which immediately evaporates, a very small hole in a hose which produces a jet of water so fine that you'll only find it if you happen to put your hand into it, and many more.

Thu Jan 01, 2009 2:21 pm

it has only recently started to use water after a hose went on me,its a real pain

Thu Jan 01, 2009 2:32 pm

Mine uses water on long runs, but that's the only time it does. If I do 200 miles in one sitting it'll need topping up, but using it for 2-300 miles in town it doesn't use a drop. Probably HGF knowing my luck.

Thu Jan 01, 2009 3:17 pm

Also have a feel of the carpet in the passenger foot well. You may find some coolant getting in there from the heater matrix/heater matrix valve. Like mine

Thu Jan 01, 2009 6:17 pm

burgoil wrote:it has only recently started to use water after a hose went on me,its a real pain

Go back to the same hose. Check the spouts it is fitted to for leaks.
Alloy spouts may become furry or pitted and allow a tiny trickle by.
Plastic spouts (like on a radiator) can suffer from hairline cracks, especially if jubilee clips are used and over tightened.

Was the system fully and correctly bled after the replacement? Perhaps an airlock happened, left a full reading for the coolant, but the movement of the coolant managed to escape to the expansion tank... unlikely though!

The m20 usually stays well airlocked!

Thu Jan 01, 2009 8:34 pm

yeah i bled it up after the new hose,i will have a good look at it an bleed again.
i keep topping it up once a week at minute.

its a real pain

Fri Jan 02, 2009 3:05 pm

hi i had a leak coudnt find it any where untill my merchanic see some antifreeze stain on my bumper and it was my rad leaking slightly from the top of the core only when it bulit up a litle pressure but enough to see the water tank go down i started with some rad weld it worked then it found another weak point in the rad and done it again so ive changed it now its spot on dont use any at all and also check to see if when you have drive it and its nice and warm check the water pipes have pressure if not its deffently leaking out some where let me know regard scott