How to find a water leak in cooling system?

[OllieVR6 0]

Being a bit of an amateur I need some help fixing a leak that I know exists, but can't find. What's strange is that sometimes it looses water over time, maybe a few weeks, other times it can dump a load of water in a few hours, however it never looses ALL its water, but always stops just under the min line on the header tank. Once I drove to work, left the car for 7/8 hours, came back and it was almost empty, but then I topped it back up and it was fine for ages again.

 

My main problem is that I know not running G12++ can cause head problems, but I can't afford to keep throwing it in just to have it p1ss out again, so I put some cheaper stuff in it so that over the harsh winter it didn't freeze up/expand/cause more problems. Now that I want to drive it more frequently I want to find/fix the leak put some nice new G12 in and actually drive it.

 

I recently had a similar problem on my Clio (randomly leaking at varying speeds) and it turned out to be the thermostat housing (diagnosed and fixed by a real mechanic), would that be the best place to start? If not, what else can I do? I have already had a look at the obvious pipes coming from the header tank and radiator, and they are either not leaking or leaking so slowly I can't see it.

[davidwort 0]

look for traces of crystallised coolant around hoses, clamps water pipes etc, the header tank overflow pipe (under the side cover on the tank) it may be that the header tank cap seal is damaged and the system is blowing water out.

 

Cardboard left under the car over night can help trace where water might be dripping from.

 

I'm assuming you haven't got water in the oil, white smoke (steam) from the exhaust or a smell of coolant inside the car (possible heater matrix leak)?

[Album56 0]

My G60 had a similar problem & although I could never see where the water was going I could smell hot coolant when I opened the bonnet with a hot engine & the coolant level would go down over 2 or 3 weeks. Eventually I saw water dripping under the car & it turned out to be the flange seal on the end of the head. Bought new flange with O ring & now its more coolant tight than its been for years. It seems coolant had been seeping out when under pressure/hot for years as steam vapour but was never bad enough until that day to show up. So head flange seals or thermostat housing would be my first places to check.

[OllieVR6 0]

I'm assuming you haven't got water in the oil, white smoke (steam) from the exhaust or a smell of coolant inside the car (possible heater matrix leak)?

 

Ok so I'll take advantage of the nice weather and put some cardboard under the car, that's a good idea.

 

I'm 99% sure it isn't the matrix, there are no leaks in the car and the only faint smell of coolant is when you first turn the blowers on and that is probably because I only did the matrix last summer.

 

The car is due an oil change so will check that there is no water in there, but there wasn't anything on the dipstick or around the filler cap the last time I checked.

 

What would cause steam to come from the exhaust, and when would it be most apparent? Is that something to check when the engine is cold or hot?

[davidwort 0]

 

What would cause steam to come from the exhaust, and when would it be most apparent? Is that something to check when the engine is cold or hot?

 

was just thinking headgasket (leak from water jacket into cylinder) which would be more than just the condensation you get on a cold engine, a few drops of water in the exhasut can make quite a cloud.

but that was just a possibility, worst case!

[OllieVR6 0]

Thanks for the input (both of ya). I will go away and play and report back :grin:

[hodaz 0]

A common place for leaks on the VR6 seems to be around the thermostat housing and crack pipe.

[OllieVR6 0]

Crack pipe.

 

I'm hoping it's not this, seem's like a pig to change.

[dbug 0]

just found mine, the flange on the head that the return matrix pipe fastens to.

 

the machine moulding line when it was made has started to weep, £10 later from europarts and she will be water loss free this weekend ( fingers crossed )

[dbug 0]

p.s the coolant should be a 40% mix so i use the first empty bottle to make the mix in that way you know that you always have the right strength :wink: