Flushing Coolant System

Hi,
I'm looking to flush my coolant system/radiator and have read the guide, but am looking for a little more guidance. Do I need to use distilled/deionised water or can I just use hose water? Do I need to add a flushing aid? Is there any specific parts to remove from the system to flush? I have heard things about radiator hoses being removed. Any guidance would be great. Thanks.

Hi

Do I need to add a flushing aid?

Why are you flushing it?

Do I need to use distilled/deionised water or can I just use hose water?

Flush with the hose and when its flushed and empty of hose water, use de-ionised water to dilute the concentrate or just use ready mixed.


Refill properly with the C3 Coolant guide




how to flush the C3 cooling system topic, but it depends why you are flushing. It usual to just remove the radiator hoses and flush the radiator ad then flush the rest of the system that is now exposed.

There's a brown sludgy substance in the tank, and I don't think its been changed in the 14years its been going as its only done 25000 miles.

Joshuap03 wrote: ↑Fri Feb 26, 2021 11:08 pm There's a brown sludgy substance in the tank, and I don't think its been changed in the 14years its been going as its only done 25000 miles.

Well, yes, then. A flushing compound (like this) wouldn't be wasted on brown sludge.

The top radiator hose may have the factory clip fitted.

They can be reused, but it may be prudent to a spare jubilee clip available should the factory clip not be reusable.

The lower hose has a reusable o-ring connector.

There is a drain point that can be used to help flush the main pump circuit of the C3 cooling system.

it is marked as 4 (the bung) and 5 (the sealing o'ring) and is located on the rear of the engine.

But this drain point only appears on the diesel engine, unfortunately it is not a feature on the TU petrol engines as pointed out below

Citroen-Driver wrote: ↑Sun Mar 07, 2021 11:43 pm There is a drain point that can be used to help flush the main pump circuit of the C3 cooling system.

it is marked as 4 (the bung) and 5 (the sealing o'ring) and is located on the rear of the engine.

That bung is not on the TU3JP or TU5JP4 engines. It may be from a later petrol or a diesel engine but the arrangement does not look familiar to me.

You will need to disconnect the heater hose on the fire wall and dangle it under the engine to achieve the same result for a TU3 (1.1 8v or 1.4 8V) or a TU5JP4 (1.6 16V).

Ozvtr wrote: ↑Mon Mar 08, 2021 9:47 am

Citroen-Driver wrote: ↑Sun Mar 07, 2021 11:43 pm There is a drain point that can be used to help flush the main pump circuit of the C3 cooling system.

it is marked as 4 (the bung) and 5 (the sealing o'ring) and is located on the rear of the engine.

That bung is not on the TU3JP or TU5JP4 engines. It may be from a later petrol or a diesel engine but the arrangement does not look familiar to me.

You will need to disconnect the heater hose on the fire wall and dangle it under the engine to achieve the same result for a TU3 (1.1 8v or 1.4 8V) or a TU5JP4 (1.6 16V).

Thank you Ozvtr

I will amend my post to reflect your information