Citroen zx heater/ thermostat question.

putting in radiator sealant will have blocked the fine tubes of the heater radiator. flushing out all the sealant and replacing the heater rad will fix the fault.

Sounds like the thermostat is ok. does it have a temperature gauge and is that getting up to temperature? Are the pipes to the heater from the engine bay getting hot?

I suspect the radiator sealant has blocked your heater radiator. It may also block your main radiator and cause the engine to overheat. Sounds to me as if you need to replace the heater radiator but if you do so you should thoroughly flush the engine coolant, maybe even remove the main radiator to flush it with a hose pipe. Disconnect all of the coolant hoses and flush everything in sight to get rid of the sealant.

Do you normally run it with the correct level of antifreeze? If you know that the antifreeze also protects the system from rusting and the hoses perishing then I'm sorry to nag but some people think it's only for winter and just use water then wonder why their cooling system falls apart :-)

Thats because you've blocked it up with that radweld s*it.

So the heater matrix is blocked up with radweld....

No, there is still enough flow to give good heat.

It looks like a new stat has sorted it.

So why would a new stat increase heater temp??......anyone??

Oh yes, and the rad sealant s*it has worked well ................ so far.

By restricting the coolant flow on cold days, you get faster warm up (or

Normally because the old one wasn't sealing.