Coolant Leak- 5 days after buying!

G

GazDerby

Member
Had my Z4 for 5 days and I hve a problem :evil:

I checked the car over this morning and the coolant level was fine, slightly low, with the bob just under the filler cap level. Didn't top up.

Went for about a 30 miles drive and parked up. When I returned to the car, there's a puddle. No drips coming out so I decide to drive to the motor factors to get some radweld.

The shop was already closed :x so I decide to pull over and check if there's any drip now. There isn't- its a flood, absolutely pouring out. I decide to get home which is only about 5 miles. I carefully take the cap off before moving to top up before I drive off again and its boiling up so quickly put it back on again and crawl home.

The oil temp was fine, never over half way. The coolant light went off once moving.

I got home ok and on inspection, the leak is apparently coming from beneath a larger hose going into the tank, just beneath the filler cap. It's a hot hose so I guess it is a hot water return to tank line.

After a few mins, it stopped leaking either as it was out of water or cooled down enough.

I have topped up again and run the engine and got the fan going again but no leak again.

I'm letting it cool overnight and will take a look tomorrow.

Thought and comments?
I've put on a photo-the water was coming from just below the metal band.

IMG_1118.jpg
 
wouldn't panic just yet , the major spillage could well be overflow due to being overfilled .
don't top up with tap water though , decent anti freeze will do
leave the car to totally cool down then top the fluid so that the dipstick in filler neck just about moves off the bottom . go 100ml at a time ?
( this dipstick fluctuates wildly from cold to warm so overfilling is very easy done)
then drive until max temp reached again & maybe you,l get the low coolant light on dash ?
if so top up a little again , maybe less than 100ml until the dip moves ?
at all times make sure you are fastening the top tight , , ,
just repeat the above until the car neither spills coolant or has coolant light on , , , ,
how do i know this ? cause i had the same happen to my previous BMW 6 series & still remember the panic at the pool of fluid :)
let us know how you get on :thumbsup:
BTW ,there is a bleed off to release the air pressure but i have no idea where it is :?
 
When you bought the car, had it been regularly used in the weeks before you bought it? I had the same with mine. It has been stored for a number of months. The pipe to the expansion tank had dried out and the seal broken. As soon as the coolant system got up to pressure, it started leaking. No more than 5 miles down the road.

Turned out the water pump had also corroded from lack of use and another coolant pipe had a similar issue. As soon as all were replaced, the problem was fixed and hasn't resurfaced in the past 6 months...
 
Whatever you do don't put radweld in. It's at best a bodge job and you need to find the cause.

Did you buy private or dealer?
 
Thanks for the replies.
I've already filled up the tank but like a narna it was still warm so it will probably be over filled now. I may syphon some out again.

The car had been used occasionally before I bought it so i don't think that is the issue. I was a private buy so no going back to a garage.

As I have been driving the car every day this week without issue and then this morning I took the cap off to check the level for the first time. I'm wondering if it was screwed on properly.
I don't think that is the case but we'll see when cold and runs again.

I didn't fill it up this morning so I don't think it was overflow.
 
if the cap wasn't fully tight the pressure after your 30 miles could easily have made the coolant overflow ,
the system is designed to let off excess when needed
 
Just had a quick check and the engine is almost completely cold and the bob in the filler neck is right down again so hopefully not overfilled.

On putting the cap back on it goes tight as I would expect but then you need to turn it even further quite hard to get another 2 rotations on it.

Fingers xd that was it! :roll:

Is there a recomendation on coolant with af already in it to use (brand etc) or tap water + antifreeze ok?
 
Wooooah... Are u sure it's the coolant ant NOT the air con unit???????

The air con unit always leaves a puddle under the car on a hot day, scared the pants off me years back & lucky I had someone with me who knew better

Hope it's just this
 
GazDerby said:
Just had a quick check and the engine is almost completely cold and the bob in the filler neck is right down again so hopefully not overfilled.

On putting the cap back on it goes tight as I would expect but then you need to turn it even further quite hard to get another 2 rotations on it.

Fingers xd that was it! :roll:

Is there a recomendation on coolant with af already in it to use (brand etc) or tap water + antifreeze ok?
Click to expand...

have you had the coolant warning light on dash ?
 
Im pretty sure it isn't the aircon, its coming from below a radiator hose.

The coolant light was on the dash when I first left and then went off. It then came on again as I was abou a mile from home and stayed on.

I've not turned the engine on again this evening but its not on at ignition point 2.

Why do you have a problem with tap water? I don't want to have to syphon out unless I need to.
 
tap water if left in system causes rusts :o
pretty sure mate all you need to do is find the correct level of coolant . . this will take a few days as the system is variable dependent on air & engine temp , , ,
just monitor & keep adding small amounts whilst not losing any . . don't flap at the warning light , ,eventually the level will be right & the light will show no more :)
stone cold with dip just bobbing free but not showing over the top seems to do the trick on my 3.0 Zed :thumbsup:
 
Well, topped up with coolant this morning back to normal level when cold and been for a couple of miles spin to get up to temp.
So far, no leaks. :D

My mate has been over to check it over and he is going with the numpty theory that I hadn't tightened the cap enough as it has to hold 1.4lb of pressure and unless absolutely tight, it wouldn't and would leak.
The other thing he pointed out is that the radiator hose next to the filler that I thought may be split is actually the water to engine intley not return which makes sense as the hot water would be at the top.

We'll see how it goes with a longer drive later. Off to the motor factors to get some more coolant in case and can do the top up and check as recommended.
:driving:
 
mr wilks said:
tap water if left in system causes rusts :o
Click to expand...

And de-ionised water doesn't? You'll find its just as bad!

The reason you shouldn't put tap water in is if you're in a hard water area as it will leave deposits in the engine that are harder than rust. Antifreeze contains corrosion inhibiting compounds (usually phosphates) that leave a crystaline layer on bare metal it passes over to react with the metal and leave a barrier from it corroding further.

As said before, please don't put rad weld in - once it comes into contact with water, it reacts to create a chemical that then changes its consistency in contact with air - good if you have a pin leak - bad if you have an air block in the system as it will gum up your cooling system.
 
It should be if you get the kit as most modern tank are anti-cyphon.
I'm sure if you googlie it there are ones easily available.
The guy I bought my house from left one in the garage :wink: it just looks like a piece of hose, a container/measure jug and a squeezie pump. The trick is to get the hose through the pipe to the tank and past a baffle.
 
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