Technical How to 'bleed' air from the coolant system.

[Superboy]

I'm thinking of changing the coolant on my G. Punto Sporting. The engine is the 1.4 16 valve StarJet . I've got 3 litres of Paraflu UP but.....

Does anyone know where the 'bleed' valves are - or whether it's got a self air 'bleeding' system? Also, how do you empty the old coolant? it's got no bottom radiator hose as such (only a half way one!) - it does have a hose connector at the bottom of the radiator though.....Maybe 'T' could help?

 

[marty61]

On my 1.2 there is a drain valve bottom right (the hose connector) and a bleed screw top left on the rad (hidden under the slam panel) as looking down facing the windscreen. The bleed screw is facing upwards and you have to lean over a bit into the engine bay to see it.

 

[Mattyk]

leave it running with the coolant bottle lid off, the water starts to bubble and all the air comes out

 

[Superboy]

There's a bit more to it than that.....
Thanks anyways.....'T' where are you?!

 

[marty61]

Drain the old coolant via the drain tap at the bottom of the rad. Fully tighten the drain tap. Fill the system slowly with the bleed screw on top of rad open until coolant appears from the bleed screw.Tighten screw. Fill expansion bottle to max mark and fully tighten pressure cap. Start engine and allow to idle for 2 mins. Remove the air from the circuit by pumping the accelerator regularly and gradually (every 30 secs) up to a speed of around 3000 rpm. This operation should be carried out until the thermostat opens and the fan switches on and off at least 3 times. During this operation keep the climate control system switched off to prevent the fan from coming on for reasons unconnected to the heating of the coolant. If there is a noticeable drop in the level in the tank below the MIN reference during this stage, let the engine idle and open the cap very carefully, topping up the fluid to the MAX level, then close the cap fully and remove all the air from the system.
- Then switch off the engine and leave it to cool down.
- If necessary, top up with the specified fluid to the MAX notch

 

[Andy Monty]

i think there is more than one bleed valve TBH

 

[marty61]

My post quoted from Fiat workshop manual

 

[Andy Monty]

My post quoted from Fiat workshop manual

fair enough just been looking at one of the older punto guides and it shows one on the radiator and one behind the engine

 

[marty61]

fair enough just been looking at one of the older punto guides and it shows one one the radiator and one behind the engine

No prob m8. If i wasnt sure i wouldnt have said so. No point giving duff info

 

[Superboy]

Fantastic - Thank you Martyl 61 for taking the time to pass on the information - much appreciated. Does it give any direction as to how to actually gain access to the bleed screw?

Andy Monty a BMW 320i that I own only has 1 'bleed' valve on the radiator near the expansion botttle....it doesn't have a valve located at the back/upper most part of the engine.

 

[marty61]

Looking at mine the only way to undo it seems to be with a ring spanner. Take care though as it is a plastic screw and liable to break if too much force is exerted on it. Dont overtighten it.

 

[Superboy]

Thank you very much for taking the trouble to check - much appreciated.
I'll go and get a ring spanner tomorrow.