Isuzu Trooper Owners Club UK™

Pennywise · ** Joined: 19 Sep 2013 Posts: 71 Location: Derby

would a knackered thermostat cause the heaters to blow cold air? Thanks matt

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griffter · Posted: Sun Feb 02, 2014 15:29 Post subject:

possibly or might be dash unit playing up as mentioned on recent post

Browndoff · Posted: Sun Feb 02, 2014 17:26 Post subject:

Once the engine warms up to FOP [as seen on the dashboard Thermometer], the water pumped through the heater matrix should be hot-enough to allow the fan to blow some heat into the cab - even before the Thermostat opens to allow this hot water into the radiator to be cooled down.

The cab's heater-matrix gets 'preferential treatment' in this regard. If the gauge shows normal temp and the fan still blows COLD air - then the problem is likely to be between the heater-controls and a blocked matrix.

If so, I'd start with a simple flush through the heater matrix plumbing. It's readily accessible - just two easily-seen pipes running into the bulkhead near the oil-filler-tube. Remove the rubber-pipes and attach a garden-hose to one metal tube - then turn ON the tap. This would push out any muck in the matrix and then the water should flow full-bore, clean and freely through the other pipe. When 'all's well' - just reconnect the original hoses and top-up the radiator with normal coolant-mix. Run the engine and any air will bubble out at the rad-cap in a few minutes.

If you're lucky, that will solve the problem in one easy go! Otherwise the problem lies with the controls.........
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2002 LWB Trooper 3.0L
I've done some major repairs, including replacing half-shaft, replacing fuel-injectors etc.

Pennywise · ** Joined: 19 Sep 2013 Posts: 71 Location: Derby

Excellent thanks for that

Pennywise · ** Joined: 19 Sep 2013 Posts: 71 Location: Derby

Well i flushed out the system and no muck! So its either full of sediment and wont budge or theres another problem!!!
Thanks for any ideas

Browndoff · Posted: Mon Feb 03, 2014 20:36 Post subject:

"Well I flushed out the system and no muck!" By that I assume you mean that it's now flowing freely and clean - in one pipe and out the other.

In a way, that's hard luck! It means that your problem lies in the control system - which includes the water-valve which admits the hot water into the matrix. If it's flowing properly through the matrix [and you can shut it off with the valve] - then the problem must lie with the controls - and may be more complex.

It seems likely that would involve stripping out the matrix to clear the air-ways and ensure effective operation of the control-system.

If there has been a misunderstanding - and you DID NOT get water to flow THROUGH the matrix - and/or you can't control it with the Temperature-Control-Knob - then THAT'S where I'd start - 'cos that Knob is supposed to control the water-valve.
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2002 LWB Trooper 3.0L
I've done some major repairs, including replacing half-shaft, replacing fuel-injectors etc.

Pennywise · ** Joined: 19 Sep 2013 Posts: 71 Location: Derby

Yes the water was moving freely and clean. So the control knob would control the water going in and out would that depend on which pipe i attached the hose to?

Gribble · Posted: Tue Feb 04, 2014 0:03 Post subject:

Way wrong Mr B ,the water flows hot through the heater matrix all the time its the flap over the matrix that controls how much hot air comes into the car.

I would start with looking at the rods and levers moving in time to the dials and if its a Bighorn with the electronic control panel as per the other post look at that too .

" which includes the water-valve (WHAT) which admits the hot water into the matrix. If it's flowing properly through the matrix [and you can shut it off with the valve] - then the problem must lie with the con"

Do try and keep up with modern tech lol
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crusader · Posted: Tue Feb 04, 2014 7:35 Post subject:

Must admit, I was wondering where this "water valve" was?
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Browndoff · Posted: Tue Feb 04, 2014 16:33 Post subject:

I must apologize to ALL for causing confusion - as has often been mentioned before - 'presumption' is the very OPPOSITE of understanding!

As Mr G. has said - it's most likely a fault with the control-rod system - which, unfortunately, will require some stripping-down of the front panelling to gain access for further examination.
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2002 LWB Trooper 3.0L
I've done some major repairs, including replacing half-shaft, replacing fuel-injectors etc.