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        General >> Problems >> Heater
        
(Message started by: Highlander on Feb 8^th, 2007, 11:27am)

Title: Heater
Post by Highlander on Feb 8^th, 2007, 11:27am

Heres one i cant think of hearing about before ;D

96 24v Ultima with climate control

heater works perfect while the car is moving above 40mph the slower the car goes the colder it gets, if the car is stationary with the engine running it blows cold air.

No fault codes present, variable fan speed goes up and down as normal, have tried reset, changed pollen filters, flushed matrix (dont think that will have anything to do with it though)
Coolant level fine, not losing any, no airlocks, heater pipes both hot

any ideas? ;D

Title: Re: Heater
Post by scorpio_man on Feb 8^th, 2007, 11:42am

hi stuart

is the a/c icing up?

water pump? less flow at slower speeds?

strange ???

Title: Re: Heater
Post by martin_rowe on Feb 8^th, 2007, 11:43am

T/Stat &/or blocked matrix problem.

Title: Re: Heater
Post by TiberiuS on Feb 8^th, 2007, 11:47am

Ummm...wild guess, but anything to do with the solar sensor on the dash??

Does the Scorp have baffle motors to control the amount of hot/cold air??

If you see straws, grab 'em ;D

Bruce :)

Title: Re: Heater
Post by Simmo on Feb 8^th, 2007, 11:48am

Stuart, Have a read of THIS (http://www.fordscorpio.co.uk/aircon.htm). If you scroll through you will see after the 'sun sensor' a note about a speed sensor and how speed affects the Climate Control. Quite what or where it is I don't know but it is certainly a feature. As your problem is 'speed' related could this be the clue?. HTH. Mike

Title: Re: Heater
Post by Highlander on Feb 8^th, 2007, 12:27pm

Thermostat is working fine, temp rises and stays in the middle as usual, returns water to reservoir once open(gauge verifed with OBD)

Dont see how it can be the matrix or surely it would work the other way? i have heat when moving, cold when stopped, fan blowing normally.
if it was blocked wouldnt it be warm only on a slow fan speed and when stopped?

Water pump seems to run fine, usual pressure, returning water to reservoir ok.

Fan alters speed with vehicle speed so seems to be working ok.

Does it whether AC is on or off, i'm stumped! ;D

I'm thinking theres some sort of blockage in the airway only forcing air in when the car is moving??
If I drive at 40 the heater is roasting as normal and fan speed rises and falls to maintain temp as normal, its only when going slow or stopped it goes cold

Title: Re: Heater
Post by Simmo on Feb 8^th, 2007, 1:02pm

Stuart, Could it be as simple as the pollen filters being clogged?. The article I put up goes on to talk about lack of air to the cabin if the filter is u/s?. :)

Title: Re: Heater
Post by Highlander on Feb 8^th, 2007, 1:08pm

changed the pollen filters already Mike, tried it with them out, no difference

Title: Re: Heater
Post by martin_rowe on Feb 8^th, 2007, 1:28pm

put some revs on while standing, increase in coolant flow to matrix.

Title: Re: Heater
Post by Highlander on Feb 8^th, 2007, 1:34pm

tried that Martin , i think its more an "air" problem than a water problem, heater pipes are both scalding hot at all times

Title: Re: Heater
Post by Mike_Floutier on Feb 8^th, 2007, 2:57pm

I don't much about the heating but if:

1. The fan is blowing the air, and
2. The heater matrix is hot,

as they are, surely either:

1. The doors that send the blown air (as opposed to ram air) past the matrix are not opening - ie only ram air is heated, or

2. The doors are opening incorrectly - either the system needs a reset OR maybe it's this speed sensor business mentioned above.

Mike

Title: Re: Heater
Post by Mike_Floutier on Feb 8^th, 2007, 3:06pm

Ok, sorry, I just read the blurb about the speed sensor so it shouldn't be that.

But, looking at the info. on "resetting the system" it takes care to differentiate between interrogating and resetting.

Have you reset the system? I ask this as I now remember a very similar fault in mine a year or so ago. The "doors" would seem to be stuck in one position. In my case I think it was open - ie v hot all the time.

I seem to remember that I had to reset it several times before it was sorted.

Mike

Title: Re: Heater
Post by Highlander on Feb 8^th, 2007, 3:07pm

Systems been reset Mike..

Thats what i reckon, somethings blocked, looks like it will all have to come out, but it works perfectly at 4omph and above :)

Title: Re: Heater
Post by martin_rowe on Feb 8^th, 2007, 3:50pm

still a blocked matrix

Title: Re: Heater
Post by martin_rowe on Feb 8^th, 2007, 3:52pm

if memory serves me right the design allows coolant to go in & out without haveing to go right through the matrix, hence low flow through heat exchanger part.

Title: Re: Heater
Post by Highlander on Feb 8^th, 2007, 4:44pm

How would that work Martin?
I cant get my head round the mechanics of how that would give the symptoms I have.

Title: Re: Heater
Post by martin_rowe on Feb 8^th, 2007, 5:10pm

low engine speed = low coolant flow. high engine speed = higher coolant flow = more available heat to exchange. try back flush matrix, fill with caustic soda for a while, or even household bleech for a few hours, flush out then try it, you should see some improvement.

Title: Re: Heater
Post by Highlander on Feb 8^th, 2007, 5:23pm

I have flushed it well.

Still doesnt compute Martin, its road speed that affects it, not engine speed.

I can sit at 70mph at 2500 rpm and its roasting hot
At a standstill I can hold it at 4000rpm forever and not a bit of heat

Title: Re: Heater
Post by jonnycab on Feb 9^th, 2007, 12:49am

Your right Stuart....it doesn't make sense ???

All I can think of, is at speed, more pressure is produced by the water pump to force the coolant through the matrix, & at tickover a lot less.....this would point to the matrix veins being restricted.

But as you say, both pipes are hot at tickover....but are they red hot?...You shouldn't be able to clutch them for too long without wanting to let go ;)

How long, from starting the car, does it usually take for the heater to blow warm air ?

My new matrix, which I fitted nearly a year ago, still only takes a couple of minutes to start blowing warm air, even with the temperatures we've had recently.

The only other thing I can think of is that the water pump impellor blades may not be completely intact anymore :)

Title: Re: Heater
Post by martin_rowe on Feb 9^th, 2007, 8:35am

exhausted now.
know where my money is though.

Title: Re: Heater
Post by Highlander on Feb 9^th, 2007, 11:06am

About 2 miles from the house the heater kicks in as it always has.
The pipes are red hot at tickover you cant hold on to them.

I seem to keep repeating this but I cant see how its a water/pressure/pump problem when as I said previously the heater blows red hot at 2500rpm at 70 mph but when sitting still and holding it at 4000rpm (which as far as i can can see would give more pressure/coolant flow) the heater blows stone cold, it doesnt give even a slight heat.

If the matrix is working great at 2500rpm how can it not be working at 4000rpm??

Title: Re: Heater
Post by TRACEYS_LIMO on Feb 9^th, 2007, 11:18am

:( not fun in this weather

Title: Re: Heater
Post by tintin on Feb 9^th, 2007, 11:21am

if its speed related not engine related, then could it be something along the lines of heater not working/blocked, and you are just getting hot "engine" air forced through at speed, but normal cold air blown at standstill? hole in the air ducts somewhere?

probably way off, but my best shot ;D

Title: Re: Heater
Post by Highlander on Feb 9^th, 2007, 1:34pm

Dont think so Sam, you cant hold your hand for long in front of the vent when moving, its burning hot so not engine heat alone

I think its something in the airways, must be opening and closing relative to vehicle speed.

I think its a dash out job to find out the cause :-/

Title: Re: Heater
Post by Octavian_P on Feb 9^th, 2007, 3:25pm

Hi Stuart, just a guess, next to the AC evaporator, theres that vacuum operated motor, that allows air to enter from outside or just recycle the inside one. Maybe it's halfway stuck. If you put the blower fan on maximum (manual) does it bring loads of air inside ?

Title: Re: Heater
Post by Simmo on Feb 9^th, 2007, 3:47pm

Stuart, following Octavians' theme, as I see it the only way for air to get into the 'system' is via the narrow inlet above the pollen filter, and after that the only thing able to obstruct it is the re-circulation flap. Shown HERE (http://www.fordscorpio.co.uk/images/acevaphousinglabelled.gif). Is it possible that there is something clogging the inlet or that the flap only opens with sufficient inward air pressure ie;when car is moving forward. Could the pollen filter be in the wrong way round?..not sure if that would 'restrict' flow but there must be a reason for the 'flow direction' arrows.