Water forced out of top of radiator

[Raz316]

It looks like water is being forced out of the top of my radiator if I drive it for a while.

Temperatures stay at the quarter mark and it only goes slightly higher when in traffic.

Any idea what'd cause this?

Cheers!

[smithy318i]

Your Rad water should only go to the line in the expansion tank.

Blockage?

Flush the system with water from a hose. once the overflowing stops put in anti-freeze.

[bullitt]

Sounds like it could be pressurising the cooling system a possible head gasket fault..

Try another rad cap first..

[Raz316]

Cheers smiffy

I've always filled it up to the line, ill try flushing it.

[Brianmoooore]

If your rad cap doesn't have a yellow disc on it's underside, then change it NOW. It was the subject of a recall years ago. If your's is black underneath, then take yuour VIN along to your dealer, and if it hasn't been changed already, and someones changed it again, they should give you a nice new one.

[Raz316]

ta you lot,

so I should be expecting a yellow disc here...

[Brianmoooore]

Thats right, yellow disc on the bottom. That's an old one in the picture.
IIRC, Problem is that they can overpressurise the cooling system and force water out of places like the radiator end seals or burst hoses. In some cases it was the heater matrix or valves that failed, spraying super heated water on to the driver or passengers legs, which prompted the recall.

[Richy325iTouring]

If your rad cap doesn't have a yellow disc on it's underside, then change it NOW. It was the subject of a recall years ago. If your's is black underneath, then take yuour VIN along to your dealer, and if it hasn't been changed already, and someones changed it again, they should give you a nice new one.

is that true
thinks its a fone call to rydales monday then

[Brianmoooore]

I've had two E30s come my way with old type caps and signs of water being forced out where it shouldn't be, and I've had three new caps out of my local dealer in the last three years.

[Raz316]

much appreciated, gonna go find a local dealer then now!

[tourer-dan]

As the pressure cap doesn't affect the pressure of the system directly, it might be worth checking the other solutions as well as changing the cap, because if you simply install a cap with a lower rated safety valve, it will simply release pressure earlier than the black disc type.
Basically what I'm saying is whether you have a black of a yellow disc, it won't stop the coolant being released, it will just come out sooner with the yellow cap.
Hope this helps.

[Brianmoooore]

As the pressure cap doesn't affect the pressure of the system directly, it might be worth checking the other solutions as well as changing the cap, because if you simply install a cap with a lower rated safety valve, it will simply release pressure earlier than the black disc type.
Basically what I'm saying is whether you have a black of a yellow disc, it won't stop the coolant being released, it will just come out sooner with the yellow cap.
Hope this helps.

The yellow cap isn't lower rated - it just works properly.
The safety related failure of the black cap is when it over pressurises the system. This doesn't mean that the (now very ancient) black cap can't fail the other way and not give enough pressure, and so lose water.

[orkboss]

Are patent ones supposed to have a yellow cap as well. I doubt it and is this for all types of engine or is it just the six cylinder jobs.