Hi there.

My wife has a mk5 1.25 16v fiesta and she is comlaining of the heaters been cold when she is driving to work.

She works about 25miles away and she says sometimes the heaters just to say get warm and other times its just really cold.

I put a heater cotrol valve on it a few weeks back but she says its still cold.It was a cheap aftermarket valve that i put on.Iv had a quick look tonight at it and felt the heat of the pipes going into and out of the valve.All 4 pipes are hot which makes me think the valve is working ok.The heaters were hot too.

Any help would be nice. Thanks....

 

try back flushing the matrix incase its got some crap in it affecting the flow

 

What he ^^ says, other possibility is a faulty thermostat, this is easy to tell by seeing what the reading on the temp gauge is.

Martin

 

if it's the thermostat, on mine they had to remove the air con pump to get to it, so lots of work to change, but seeing as someone had bodged the old one on with some silicone, it had to be done

heating was nice afterwards

 

is the engine definately getting upto temp in these cold conditions?? when driving the cold air can be enough to cool the engine right down meaning the heaters don't get very hot.

 

Easiest way to fix it is to give her a slap glenn. That'll stop the moaning!

 

Surely the pipes going to the heater valve would be cold if the thermostat wasnt working right.

I checked it again tonight after we just got in and the pipes in and out of the valve were hot but the heaters in the car were just to say warm.

 

Sludged up matrix I'd have thought!

 

Easiest way to fix it is sell the old dog lol.

 

The car or the wife?

 

Where abouts is the thermostat at then on these fiestas.I thought it was on the side of the engine.

 

The thermostat should ensure this is happening. Only reason it'll not get very hot is if the thermo was stuck wide open, but, it'd still get warm. If it's stuck closed, there is no way that air passing over the engine would cool it down. It'd still overheat.

 

it's in the front, under the inlet manifold mate

 

backflush heater matrix .unless the temperature rises in traffic if it does then change thermostat

 

Never, i will have a look tomorrow and see where it is.

 

Its fine in traffic.I will try and flush the heater matrix tomorrow.

 

Im pretty sure if the car is stood still and the engine is reved it gets warm.

 

Flush the matrix as it's easy to do and free and it's worthwhile doing anyway, if no luck then I would be looking at the stat, if ever in any doubt as to location just trace the top hose back.

Martin

 

true but i was thinking that maybe the water is getting hot enough to open the stat but in the cold weather not able to get upto full running temp, especially when moving. i've noticed mine gets upto temp idling on the drive but when moving the temp guage shows it running a little cooler but not enough to close the stat. it may only be 10 degrees or so but could easily be enough to stop the heaters getting upto full temp.

 

I'd expect it'd be a faulty stat if it's bad enough to notice through heaters. I check my temp whilst driving in this weather (on scangauge) and it still happily stays around where it does normally, even when driving at very low revs. Also was doing 70+ on the m25 (also through the 50 zone, in 5th, with fuck all revs), with an intake temp of -6oC(was half 12 friday night), and the car stayed up to temperature. mines got the same engine variant, the se. Albeit in a bigger displacement.

 

hmm, i think my focus can display the actual temp on the dash so might give that ago...now thinking my stat might be on its way out haha.

 

If the thermostat was faulty or not working correctly surely the pipes going to the matrix would be cold?

 

The wife has just told me the heaters were warm today on her way to work.It has been really cold these past few days but this morning it wasnt really cold.

I think the cardboard trick in front of the radiator will have to be put into action ha ha lol.

 

It does not matter what the ambient temperature is, this is the very reason for a stat I.E to regulate the temperature, so say if you have an 86 degree stat it will not open until the coolant is at this temp at which point it can get back to the rad, anything below this temperature the stat closes or slows the flow meaning coolant can not get back to the rad and so will not get cooled.

However if the stat is stuck open the coolant will get over cooled so effectively it's the same as running with no thermostat, so the engine will warm up very slowly and the coolant will not get to the correct temp hence being mirrored in the heating.

This is why the heating gets warm but never hot and when you start moving it goes cold again as the coolant is being over cooled.

Yes Focus will display the temp from CHT on the digital dash amongst a whole variety of other useful info.

Martin

 

Top info there mate. Would the pipes at the heater valve not be cold though.

 

i think the difference we are only going to see at the heaters between the engine only reaching 86 degrees and being able to reach 100 degrees is a warm cabin or a stinking hot cabin. without seeing the car in question its hard to say whats happening to be honest but i think its more along the lines of not being able to get stinking hot like she's been used in warmer weather.

 

The pipes won't be cold but they may not be as hot as what they otherwise normally would be. I.E you feeling them may just be warm, if faulty stat this will cool down with the car in motion I would defo err on the stat, other possibility would be clogged matrix but it's unlikely unless the cooling system has been neglected.

Way to test the stat is on a cold start by feeling the top rad hose, if you can feel coolant running through it then the stat is not doing it's job.

Martin

 

I dont think the matrix is blocked cause surely the heaters wudnt be going hot and cold all the time. Im now thinking it could be the stat. I just hope its not a coont to change.

 

I personally think it's the stat, I originally suspected matrix or stat as in my original reply but know I know more info. A blocked matrix can give warm bursts sometimes. Do you know what the temp gauge reading is as this will be a good indication?

Martin

 

Just incase...she does know how to use the heater control panel, yes?

 

Is it definatey there Dojj. Ive just had a look at the car now and it looks like a right twat to get at. It looks like its under the alternator with 2 pipes coming off it. The big radiator pipe coming from the thermostat was a bit cold then when the car was sat running the pipe get warm.

 

Are you taking the piss lol.

 

Kinda, but she is a woman, and you can't always be sure with them.

 

is it sorted then?

or are you going to get busy with the spanners on saturday morning