Help! Tank cap not tight? Steam? Coolant leaking! SOS!

[MyDirtyThirty]

Hi there,

About an hour ago I filled up the coolant in my mk4 golf to the max level. Stupidly, as I was in a bit of a rush, I am not 100% sure I made sure the tank cap was exactly tight as it should be. I doubted it then thought "oh it will be fine."

BIG MISTAKE.

On dual carriageway, smoke/steam coming out of expansion tank, then, as I managed to get the car to a relatives, I looked to see that my coolant was now empty, and pouring out what looks like the radiator at the front. Pink stuff everywhere.

If I re-full my coolant again and tighten the cap is this ok, or have I caused serious damage?

Thanks for your help!

Edited by MyDirtyThirty on Friday 30th September 20:46

[347Andy]

Let it cool down for at least an hour then refill the system and see how it goes is the only advice I can offer ! Fingers crossed for you :-)

[MyDirtyThirty]

Ok thanks I'll try- but how does it work that without the cap this coolant is pouring out of my car?

Edited by MyDirtyThirty on Friday 30th September 17:49

[347Andy]

If the cap wasn't on properly then the system wouldn't have pressurised and the coolant was boiling. If it has blown the head gasket then the system is possibly being pressurised from one of the cylinders. Hopefully it won't have done any damage but until you run it up you won't know.

[MyDirtyThirty]

Well Andy, update: put coolant in to the min level left it standing an hour and it drained. Seemed to be coming from underneath again. Coolant light on and a tiny amount in the bottom. Then, put coolant in at max again- it went down and I drove the car 5 miles and it went right down to min. Currently leaving it overnight to cool right down. Not sure whether this means there is a hole in the system or not?

Edited by MyDirtyThirty on Friday 30th September 20:47

[HustleRussell]

Why were you topping up your coolant in the first place? If the level was going down then presumably you were aware it was getting out somewhere?

It's overheated, air locked and was leaking anyway before the fact? Garage time.

[sospan]

You say you saw water coming from the rad?
If so it is the cause...leaking rad.
Can you see water on the ground under the car? Do you have an undertray that stops seeing this?
Any trails of water on the engine/hoses/joints, water pump?
Do these checks first to eliminate the simpler solutions before resorting to head gasket replacement. Compression test too to narrow it down.
Then...bite the bullet!