[Dwaite8076]

I took my heater core out and it was completely destroyed, it's full of gunk, a toothpaste looking gunk
The heater core top pipe is full of this gunk as well, and I have no idea how to flush it out on my peugeot 308 t7 2010
Any tips that anyone can give me?
I'm looking into doing a radiator flush as it seems to be clogged a bit too, but I need the heater core issue dealt with, I believe it's causing my car to overheat

 

[Jolbe]

Replace the heater.

 

[Dwaite8076]

Replace the heater.

Replaced the heater core but it's pointless since the system needs a flush first of course

 

[Jolbe]

I dont understand what is the question? There are additives for flushing cooling sistem. Some go into coolant, some can be used with water. You need to leave the engine running and after some time flush everything. But since you have the heater removed i would connect (bridge) the heater hoses togather and flush them from the engine side (coolant pipes at the firewall). I would remove radiator hoses and wash it separetely. Also the engine block. You wont be able to flush through closed thermostate so some dirt will remain. Wash the expansion tank also. That should be enough. But if you have the whole sistem in place (new matrix already installed) best option is to find a garage with vacuum tool to extract the whole coolant at once...

 

[Gibbo]

What's the history of the coolant changes? Looks like the coolant has broken down into its chemical property and water.

 

[Dwaite8076]

What's the history of the coolant changes? Looks like the coolant has broken down into its chemical property and water.

I think the car sat for quite a while before I was dumb enough to buy it
I think the last change they did was 2015 or so, so when I bought it, they did a flush etc but the damage was done for things like the heater core