Air Conditioning Fill Volume - for info

Technical questions and answers about the Mazda Bongo

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alang4kuf

Air Conditioning Fill Volume - for info

Post by alang4kuf » Tue Jul 04, 2006 4:54 pm

Yet more expense! Planning to go on holiday in the Bongo, in the middle of a heat wave, I was not very happy to find that the air-con didn't work.

A very friendly guy, Steve Angell of Aircool AC Ltd. (Aircool.biz), has sorted things out. There was a leak at the flange where the feed pipe enters the rear evaporator but this has been cured with a new O-ring. After a leak test, new lubricating oil, the addition of UV fluorescent dye (to aid leak detection in the future) and a re-fill of the refrigerant, all is now OK. Running flat out, the air outlet temperature was 2.5 Deg C (Cool!) despite the outside air being at about 30 C.

In the Q&A section, the refrigerant is given as R134a (correct) and the quantity 700grm. With this amount, there are still bubbles visible in the filter sight glass when running. Mine now has 800grm and is much happier.
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waycar8
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Post by waycar8 » Tue Jul 04, 2006 5:54 pm

hi alang4kuf when he repaired the joint did he take the complete unit out or did he do it from underneath?.

the reason i ask is that i have a leak in the same place and the guy i took mine to be refilled said he would have to take out the whole unit, which would mean taking off the water pipes, and bleeding the system again.

so i said no thanks.
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alang4kuf

Repairing the AirCon leak on rear evaporator

Post by alang4kuf » Tue Jul 04, 2006 8:59 pm

Hi, there are two refrigerant pipes (small inlet and larger outlet) and it was the O-ring on the flange of the outlet pipe which was leaking on mine, probably due to a bit of aluminium corrosion. It was not necessary to take out the evaporator or the water heat exchanger. After emptying the system of refrigerant, only the one pipe was pulled away (undo one bolt) enough to replace the O-ring with a new low temperature one, clean the mating surfaces and put it together again. There is enough spring in the pipe to do this. It was only a five minute job done lying on your back just in front of the rear OS wheel. Quite possible but might be easier with ramp / hoist etc. to give a bit more working space, unless you have short arms!

Hope this helps.

Alan
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Simon Jones
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Post by Simon Jones » Sat Jul 08, 2006 10:13 am

I've also noticed a damp greeny coloured patch where the pipe union is. The fluid seems to have eaten thru the foam rubber piece where the pipes go up thru the floor.

Do the front & rear systems share the same fluid? Could I get the front system topped up independent of the rear, or should I get this leak sorted first?
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waycar8
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Post by waycar8 » Sat Jul 08, 2006 10:51 am

its all one system, only way around it without replacing the rear unit is to have the pipes cut and capped before they get to the rear unit.(thats what the aircon guy told me anyway)
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Lewy

Post by Lewy » Mon Jul 17, 2006 6:12 pm

Running flat out, the air outlet temperature was 2.5 Deg C (Cool!) despite the outside air being at about 30 C.
I've had a evac, re-gas and test - all fine but I've checked the outlet temp on a run and it never got below 7.4c - although outside temp was about 35c - do people think this is about right?

I noticed also the temp would yo-yo dropping to about 8 and then up to about 11 then down again. Checked the temp in my other car and did not seem to go as low - but was more consistent and felt cooler - think the power of the fan has something to do with this.

Has anyone supercharged thier fan motor in any way - seem to remember reading about someone who got more speed out of theirs - it works on all speeds so don't think its the resistor pack which I have repaired on a few occassions.
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Post by Lewy » Mon Jul 17, 2006 6:37 pm

Not that I'm becoming obsessed or anything - but just checked the aircon temp again - the outlet temp quickly drops to 7.4 or 7.5 then climbs back up to 11 or even 12 - then starts to drop again and so on.

So as this is a slider control air con - I assume there is a thermostat that regulates the temp as to when the compressor kicks in? Anyone have any ideas about this - or if there is an adjustment that can be made - I can go back to the geezer who did the job, but I think everything he did was ok?

Or should I leave it and be thankful of any cool breeze coming out of the vents?
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Simon Jones
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Post by Simon Jones » Fri Jul 21, 2006 9:29 pm

Surely, the control is set to 18 C, then you would expect the air coming out to be in that sort of region, rather than under 10C, or am I just being dim? :?
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waycar8
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Post by waycar8 » Fri Jul 21, 2006 9:35 pm

i think coz they are from japan, the lowest temp (ambient) must be around 18 degrees, so over here the minimum is alot lower than that.


thats just a guess but it makes sense to me?
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pippin

Post by pippin » Fri Jul 21, 2006 10:10 pm

The exit air needs to be a lot colder than the desired interior end temperature otherwise it would take an age for the interior to cool down.

Factor in that the interior is being heated (by solar radiation, by the engine, by the occupants and so on) and the exit temperature definitely needs to be way below the desired temperature.

It has nothing to do with the temperatures in Japan. These vary a lot from the north to the south. On average the temperatures are not much colder than the UK and only a bit hotter (but definitely more humid) than our normal summers.
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Peg leg Pete
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Post by Peg leg Pete » Fri Jul 21, 2006 10:26 pm

Our air conditioning definitely needs a service, but tyres must come first, I agree with Pippin, we used to hire a Vauxhall Zafira for the holidays before we got a proper vehicle, the aircon nearly gave me frostbite of the fingers, but used lots of fuel to stay cool :roll:
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Lewy

Post by Lewy » Sat Jul 22, 2006 12:54 pm

I spoke to the aircon guy about the cycling temp - he said that is what is supposed to happen - if it didn't cycle the compressor would be on all the time and it would soon burn out. As it is the aircon is working and cool enough so I'm happy with it - incidently when he extracted the old fluid he took out about 550ml so it should be happier now with 800 - and there are no bubbles in the viewing window.

I still think the fan is underpowered though for the size of the vehicle.
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