Hi, Posted here last year re trouble starting my KA. Car had previously had bad leak out of thermostat housing. Previous owner blamed wife claiming the head was probably cracked.I removed head ...perfect. Checked ignition, fuel system, timing.... all good. I was stumped.

Just recently got to the bottom of it.

Removed oxy sensor and car started albeit running rough. My conclusion is that coolant had made its way into CC and badly corroded and blocked it. Seems like o2 sensor telling ECU "don't allow engine to start as exhaust gases have nowhere to go". So now I need a new CC.

my questions....

What are my chances that a secondhand CC that will do the job?

Is there anything which will indicate visually that CC is OK (or not OK)?

Are there any other Ford models which used this particular CC? Ford KA thin on the ground here in Oz and Ford new part is ridiculously expensive.

Look forward to hearing your views.

Cheers

If the car is blocked, the car probably started with the oxygen sensor removed because the gases now have somewhere to go. The oxygen sensors don't have any affect on the ecu until they are up to temperature.

A second hand cat should be fine, new would be preferable but as you have said very expensive. Have you looked into an aftermarket cat?

You can pick them up off eBay quite cheaply brand new.