Robsters

How easy or hard is it to replace the heating matrix inside a ford fiesta mk5 ? mine still works kind of but not getting much heat no more, heater valve been replaced and all pipes have been cleaned out so I can only put it down to the heating matrix is on its way out.

Rusty85

All the matrix is is a heat exchanger. If it isn't working then either the water still isn't getting through, or the air isn't. I would suggest disconnecting the two hoses and flushing the matrix backwards withe mains water pressure. If it is blocked and doesn't clear, then it is a new core. If it is blocked but clears, then it is sorted. If it isn't blocked, then either the air side is blocked by leaves or the water flow is poor( pump or thermostat?).

Robsters

new core? and yeah the water pump could be the issue i am getting heat since my mechanic fixed it but he had a hard time getting it to work but far from perfect and he thinks its a heater matrix issue but recently i noticed a slow coolant leak from my car i had water pump replaced in 2015 but i was stuck out in ireland on holiday when it let me down which was not idea so not even sure if they put a good water pump in or not but every month i have to top up my coolant level to full again, the leak is slow but from what you say this could be related to the heat being not very good?

Rusty85

It could be that the pump isn't man enough to displace air in the heater matrix, but try reverse flushing the heater first. Blocking of the air side can be tested with the fan. With the engine hot, the heating on full and the fan on full, do you get a lot of cool air (water problem) or not much air but hot (air flow problem).

Robsters

yeah its a lot of cool air with the fan on full and heat on full so from what you say a water problem? so that could be related to the pump? the pump def leaking coolant, my mechanic just told me to keep an eye on coolant level which luckly takes good month before i have to top it back up but long term prob going have to be replaced again which is annoying as its not a cheap job and i paid the earth for the repairs to get my car back to uk from ireland (nigbtmare) clearly got a dud part put into the car as well even though my mechanic says the water pump looks new, he trying to avoid repairs for me as he thinks car to old not worth spending money on it which is good of him but at the same time dodgy water pump is not good. all pipes been cleaned out infact my mechanic got heat working better than it was before from flushing the system out but its far from perfect.

Rusty85

If the heater water system is clear and the pump isn't man enough to push water through, then the pump could be the fault, but that seems unlikely unless the impellor is loose inside it. In that case the engine would overheat. Is the temperature gauge getting up to normal? If not, it could be the thermostat stuck open? That would keep the water cool and minimise flow to the matrix.
Far more likely is a blockage. Take the hose off where the water goes in to the heater valve and on the return and flush that with a hose....

badj

I had a similar thing on a 306 I fixed a few years back.

I'd flush the heater matrix, with a gurgle and then spurt (suggesting air lock) then it would be all toasty and warm, then a short while later we'd be back to room temps.

The car had a weep from the water pump, and I can't remember from memory now whether it was some sort of radweld/coolant fix stuff that was clogging up the heater matrix, or an airlock due to the leaking pump.

Either way, if you have any sort of leak on the cooling system then, unless it is the matrix itself (damp footwells), you need to concentrate on solving that first.

It could easily be a bad gasket on the water pump, which wouldn't need a new pump, but the lump of the job is in the labour anyway

Robsters

Thanks for the input into this, yeah I think the water pump is the cause when that went wrong in ireland that was about the time heat went wrong as well and now it had this slow drip for over a year now, it hasnt got any worse but its a pain the ass having to keep buying more coolant and topping it up. My mechanic is a decent guy he tries to save me money by leaving things as he doesnt think my car is worth spending money on it but if i have the car for the winter again i will have to get this sorted which won't be a cheap job, also have suspension bushes need doing to. I will have to decide if i ditch my car and get another before the year over.