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roy4matra
YaBB God
Posts: 1213
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« Reply #5 on: August 11, 2019, 10:20:22 pm » |
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the seconde cable controlls a little valve at the heater to prevent cold air coming in to the interior in winter
Not quite right. The outer cable connected to the tap opens and closes it, but also moves a second cable that goes directly back through the bulkhead to a flap in the heater box. Old heater systems used the tap to control the hot coolant through the matrix, to adjust the temperature in the car. Modern cars have hot coolant going through the matrix all the time and use flaps to control the temperature in the car (either blocking the hot air flow from the matrix or blocking the cold air coming in directly from outside) and these are called air blending systems. The Murena is a combination of varying the coolant and air blending! So you need both working. I would not dispense with the link to the flap. All this has been in the FAQs on my website for years - it is on the seventh page, and discusses how to turn off the tap fully to get cool air inside. I suppose if your climate is hot all year round and you NEVER need the heater at any time, you could dispense with the coolant through the matrix altogether, by joining the two pipes or hoses together and by-passing the matrix. But if you need the heater any time even if only for a small amount, that is not an option. Also there is one other point here. You might need the heater matrix to increase the overall cooling capacity slightly - but have the matrix under the front so the hot air doesn't heat the cabin! Roy
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« Last Edit: August 11, 2019, 10:55:32 pm by roy4matra »
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roy4matra
YaBB God
Posts: 1213
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« Reply #7 on: August 12, 2019, 09:15:22 am » |
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... We don't have much of a Winter here and I usually drive my modern cars with the aircon on in Winter anyway!
Just to clarify point this for many other car owners and people generally. Using air con. in a car at any time can be advantageous whether winter or summer and whether in a temperate climate or a hot climate. Air con. is not refrigeration as many think - it is air conditioning which is different. I know many people who only think of air con. to cool the interior, but that is not the case. In winter here in the U.K. and other places where it is cold, you can use air con. with the heater on which might sound contradictory IF you only think of the air con. as refrigeration. But air con. is brilliant at changing the humidity so it gets rid of moisture condensed on the glass far quicker than waiting for enough heat from the engine to dry it off, so it clears the misting up you get on a cold day, which hinders you seeing out, and within 30 seconds usually! We used to get customers in all the time, who had cars with air con. for the first time, and since they never read the hand books any more had never used their air con. except in summer for cooling; and didn't realise it was brilliant in winter too. I understand that in your case Ron, it is used more for cooling in a hot climate, and you probably have little need for clearing misting of screens or other glass, but I wanted to clarify this as there are many who do not truly appreciate the air con. in modern cars. Roy
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« Last Edit: August 12, 2019, 09:30:34 am by roy4matra »
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roy4matra
YaBB God
Posts: 1213
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« Reply #8 on: August 12, 2019, 09:27:06 am » |
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Thanks Roy. Now you mention it, I had read this section of your FAQ's several years ago but the old brain had completely forgotten it! It just shows that a complete re-reading should be done at regular intervals.
The question remains, however, is it possible to free up the flap in the heater box without removing the heater box entirely which looks like quite a daunting job given my problem with working under the dash?
It is a while since I last took out a heater box on a Murena, but on a standard car, without any extra fittings like audio systems that may be in the way, it is not that difficult to remove, particularly unlike most modern cars where it is buried in the car and involves stripping the whole of the dash board. But before you even think of removing the heater box assembly, you should check out the cable connections on the sides of the casing. You can adjust or disconnect the cables on either side. In fact you would need to disconnect these first to remove the heater assembly anyway! So it may be your cable back to the heater flap is incorrectly connected, or the cable is kinked preventing full movement. Or if the flap is stuck or jammed for some reason, it may be you could simply disconnect that cable, at least temporarily, to allow the full heater control movement of the tap. But it might be the tap that is jamming part way - have you checked that it does move freely from full open to full close? Is the seal inside still good enough to seal when fully closed? Because others have perished and even when fully closed do not seal any longer and therefore still allow coolant through which still means some heat in the cabin. And if the flap is stuck because something is jamming it, I would want to know what and rectify it before it can cause some other damage. Roy
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MatraIan
Jr. Member
Posts: 39
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« Reply #10 on: August 12, 2019, 03:51:31 pm » |
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Hello Ron. Coincidentally I have just removed my heater box this last weekend. It was working but slightly stiff on the cables, and as I am replacing all pipes and hoses with new and have had the engine cleaned ultrasonically I thought I would do the last piece of the puzzle and clean it out and make sure any dirty residue was not washed back in to the system. I had released the 4 nuts holding it to the bulkhead and the front compartment hoses inc. tap. (I have cleaned and lubricated the tap and it now moves freely.) This did involve lying on the floor of the car on my back so perhaps tricky for you. Once the vents were removed and the fixing behind the astray/vents it was a relatively easy. As Roy pointed out it is quite easy but mine was made awkward having to jiggle it around the extra quad amp that had been fitted by previous owner.
I could have flushed the matrix out whilst in the car but am glad I removed it for several reasons. One is, that in car flush would not have got rid of the dried lumpy dirt chunks that finally came out after several hot water soaks and drying out. Two, the matrix had a section of small leaves blocking air flow but was also blocked just as much by disintegrating foam from around the matrix and a poor foam seal to the bulkhead above the box. It had been there over 35 years.! Three, it was easier to get to spindles to lubricate. They were all moving but now move with less effort. NOTE: there is one of the three plates where one end of the spindle does not come out of the side casing and is on a bracket so cannot be lubricated without removing the heater box. Also the solid cable can be lubricated from the top and let go through the plastic casing. As it is off the car I will post a couple of pics when I get back home. Now need to clean up box casing which was in surprisingly good condition, get new foam and refit. You could try lubricating the spindle ends you can get at and working back and forth and down the white casing on the solid tap cable, perhaps with cables disconnected at box end. It is worth trying in order to keep full functionality. Failing that you need a willing volunteer to assist in removal and, as I hope to have, when trying to re-fit. For me it was worth the effort but we have different weather to you back here.! Ian
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Murena 2.2 S Red 1984, Rover 600 ti, BMW 1 coupe M sport. Mercedes C class CGI sport
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