martinnitram

As title, only had my classic 2 weeks and as with any new car i get, its had a piece of carboard under it to see whats dripping out of the thing.

So far doing well apart from water ive tracked down to the radiator overflow.

At first i thought the tank was leaking, but its not its water coming out the pipe connected to the lid, obviously doing this while the car is running and slowly dripping overnight in the garage.

The overflow tank level is showing normal between full and empty, when stationary and had a look at the radiator type cap on the main radiator filler tank (metal one) and that is full to the top with water.

Noticed a few cars with catch tanks for this overflow, is this a normal occurance on these cars ?

Cheers
Mart.

markb5888

Is there alot of water coming out?? Are you having to top it up atall??

martinnitram

No not a lot, just enough to drip on the floor after its been stood overnight, keeping my eye on it and as yet not needed topping, more annoyance than worrying.

Had the inner wheel liner out to check the tank behind and that is dry, as is the pipe connecting the under bonnet small tank to the wheel arch one.
Next time im out in it ill check the overflow pipe while its running.
And may even get a new radiator cap as well.

1 ) What happens to this water when the tank fills up, cant quite work out where it goes.
2 ) Im assuming the metal tank is supposed to full to the lid with coolant.

Cheers

markb5888

The water metal header tank is supposed to be full to top. So if that is staying full. This is a good sighn... The plastic tank at side of radiator is just an expansion tank. So as the water gets hot it raises. And as it cools the level drops. As long as this maintains level then you dont have a problem. Its when this pressurises and coolant burst out under boost. Is when you need to worry as this can be sighn of H/G failiure..

markb5888

Try new radiator cap. Or make sure its the correct one for car. I think the wrx is 0.9 bar cap... And sti is 1.3bar cap..

Then take car out drive it hard on boost. Then pull over. And see if water has sprayed out of overflow pipe..

martinnitram

Right, i went out last night and gave it some boot and pulled back straight into garage left engine running and popped bonnet.

Water had been coming out of the overflow pipe as there was a small dribble in front of rad and the pipe had a few drips hanging off the end of it.

I opened the yellow lid to check the water level and it was about 1 1/2" higher than the full level, revved the engine and the level raised and lowered a small amount, the engine was now really hot and the fan was cutting in and out.

i kept it running and was watching the level for about 10mins and had a shock when i started seeing bubbles coming into the bottom of the tank.
But id had the radiator cap off before so it was trapped air in the line bleeding through, relief ! , but the rad cap was letting pressure out for it do this.

Also while it was bubbling the water bubbles were getting quite high up the filler neck.

Anyway checked the level stone cold and its still higher than the full level by about 3/4", and the main rad cap level still full to the brim, so i think it may just be over filled with water.
Going to change the radiator cap as well.

markb5888

Yes make sure the expenshion tank has not just been overfilled. Have seen this before!!

Empty to correct level. and then retest. Fingers crossed it just be filled up to much