Heater Matrix problem,weird one.....help/advice hugely appreciated please.

[kenny.]

OHs Ford KA 1.6 Duratec again.

 

Symptoms she reported were no heater........I also noticed fan was kicking in very early when I tested the car......getting too hot really.

 

So, I went for the usual suspects on these cars and replaced first of all the Heater bypass Valve......no joy, then at great expense today replaced the complete Thermostat/housing/switch with OMP parts..............ball aching jobs but again no heater and car was boiling up after fitment. ☹️

 

So, I then started guessing at air locks/blockages. I disconected bypass valve again from heater matrix and first of all with the airline it felt blocked (matrix).............then a load of crap came out. I then attatched water hose to the matrix pipes and flushing backwards and forwards until I got a good clean flow...............However when connecting cars plumbing back up to matrix the bloody heater was cold and the car boiled over again...............reflushed once more, again water flow was powerfull, reconnected it again and car just kept spitting its fluids out and getting hot once more. Final job for the day and a last try..............to rule out C/head gasket or blocked rad I bypassed heater matrix with pipe................car ran faultlessy, temp stayed to normal and no blowing fluids out. Reconnected matrix and it went tits up again so put bypass pipe back on so car is still usable.

 

Guys, how do these matrix work please?...........I've got full bore water from the hose blasting through it in both directions..............yet connect it to the car and it seems blocked...........I admit I'm stumped........never had grief like this on any car that's stumped me as this has.

 

All ideas, and similar experiences would be welcome to hear.

 

Cheers fellas

 

PS I'm asuming matrix will be a bugger to change as well?............car has aircon too......will this be connected to the matrix???

 

 

Edited by - kenny. on 3 Dec 2012 17:22:17

[CageyH]

Stupid question, but is power getting to the bypass valve?

[kenny.]

Cheers Kev, checked I had volts at the bypass valve first off..........I got a wavering readout between 8 -15v...........I assumed if there was power it'd be OK. Other thing I've convinced myself is that a broken control unit wouldn't make car overheat.....would it?

 

Thanks again though mate

[Jonathan Kay]

Similarly... can you plumb the matrix back in while bypassing the bypass valve? Does it then allow flow?

 

Jonathan

 

Edited by - Jonathan Kay on 3 Dec 2012 17:37:17

[kenny.]

Jonathan............... That will be my first thing I do tomorrow, cracking shout .........I was just too frozen to push on with the job today and my brain was addled by the bloody thing.

 

Many thanks

 

Edited by - kenny. on 3 Dec 2012 17:37:09

[CageyH]

The car should not overheat, so I would suggest that there is either an air lock, or blockage.

 

Are you sure it is boiling, and not a duff sensor or blown expansion tank cap?

Yes - you said it was boling over.

 

You could have an airlock in the heater matrix, so you need to ensure that this is topped up when reconnecting. If I remember correctly, the heater matrix sits quite low, so you need to be careful about refilling the system.

 

 

 

Edited by - CageyH on 3 Dec 2012 17:41:41

[Stationary M25 Traveller]

Second vote for airlock in matrix.

[kenny.]

I agree Kev about the blockage...As I said I will do what Jonathan said but having had a think I'd have thought even if the new valve was naff....or the switch wasn't working water would still circulate?..........I may be wrong on that one.

 

As for the blockage, what's on my mind is the fact that these cars now run mainly plastic components with plastic bloody outlets..............both the Thermostat housing and the valve housing are plastic....................now when I removed the heater valve housing it was so brittle one of the ends just broke up...........I thought I'd retrieved the debris but can't be sure.............thought the hosepipe flush would certainly have removed any biggish bits of plastic. I wonder if there's a rogue bit still floating about...............haven't yet removed the 2 pipes from the heater to Heater valve as they look a bastard to get off and back on.........they are still connected to heater, wonder if something is lodged in one of them

 

Cheers, appreciated

[kenny.]

Kev, Ian, cheers for that............hadn't thought about "priming" the matrix but sounds like another plan..............never heard of it before though, is it a common practice lads?.......yes it does sit low, lower than the header tank for sure.

 

Still convinced it's as you say a blockage/airlock..............there just seems no means on these bloody modern cars to get airlocks out though.

 

Thanks

[CageyH]

It's fairly common to have to prime or bleed the heater matrix.

Often, there are several bleed point built into the cooling circuits of modern cars.

[kenny.]

Guys quick update............I've also had 2 pro mechanics look at this now today and as always with my problems "They've never seen anything like it before"

 

I started off by giving matrix another blow through and double flush.......great flow present and finally clean as a whistle. I then did what JK muted and removed Heater bypass Valve and plumbed directly to heater matrix...........heater still cold

 

Annoying thing is both inlet and return pipes are hot.

 

So I flushed again and replaced bypass valve...........car runs fine with no overheating but heater still cold............again flow and return are hot, I simply cannot get my head around this one.

 

Cheers.

[Molecular--Bob]

When you say heater cold do you mean the matrix, or the air coming out of the heater? The heater may have a servo flap to allow cold air in and it may be stuck open? Happens to Volvos as i know to my cost.

[kenny.]

Hi Bob, I meant the air in cabin............it's hard to check if matrix is hot as it's buried in bulkhead............pipes to and from are certainly hot.

 

Now I've heard of these flaps.........but thought they were just to switch the flow from screen to footwell etc................which does work.

 

Thanks for responding though ..I'm flippin' struggling.

[Stationary M25 Traveller]

Another stupid question - heater controls are set to 'hot'?

[kenny.]

Yep, thanks Ian .............as I say I've in effect bypassed the controls once by bypassing the heater control valve, ie giving it a direct feed........no heat still even though water from the hosepipe go's through the matrix like a goodun when flushing.

[Graham King]

Kenny, I'm sure you've tried this already, but I had a similar problem on my son's car (1.6 Fiesta) when I replaced (see my thread) the HCV. At one point the heater was blowing cold air out only even when set to hot. I came to the conclusion I probably had an airlock. I eventually got round it by removing the outlet pipe and back filling from the inlet pipe until the coolant ran out of the outlet pipe connection, and then back filled the outlet pipe from the other end. I actually did this with almost every hose and the rad. Was a right royal PITA, worse than doing the Caterham K, but got there in the end.

 

Graham.

[kenny.]

Many thanks Graham, interesting comment. I've actually flushed the matrix both ways but have not filled it both ways......I've simply primed it from the inlet only, I will try filling it as you suggest, thank you.

 

Now this "flap thing"...........is there a main flap which could be closed on the heater that is blocking the warm air maybe??............as I say when I turn the vent dial it does switch air from screen to footwell etc so I assumed all was OK on that side of things.

[Molecular--Bob]

Is water actually circulating? Thinking water pump may be FUBAR

[kenny.]

Hiya Bob, many thanks. I actually think the pump is OK. I did a test running motor with a pipe off and water flies out. To doubly confirm all was ok I made a big 2 foot loop from heater valve rather than sending water through matrix..............no problems,car did 20 miles with this set up and no traumas.

 

But thanks, I'm baffled and will look at anything............I'm even thinking electrical/fuses now, though I doubt it.

[CageyH]

Have you fixed it???

[kenny.]

Hi Kev, to cut a long story short we now reckon a rogue piece of plastic from one of the outlet pipes on the old Heater valve has made its way into the matrix, one was broken when I removed it. Although I thought I had full bore water going through heater via a garden hose my mate at a well equiped garage put a proper "blaster" on it and he reckons it's deffo blocked to a degree. We've put a system flush in today and I'm getting luke warm air now.............mate reckons it may still be just crud and will clear.......I bet it's plastic though. Changing the matrix looks simple but this bugger has aircon pipes going through the top cover of heater.............so I'm just hoping removal will not be a nightmare if this flushing stuff fails.

 

Many thanks.