AC drains - blockage in AC unit?

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SteveB
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AC drains - blockage in AC unit?

Postby SteveB » Sun Jul 12, 2009 7:10 pm

Hi - I have just had the classic "wet feet" problem following this weeks heavy rains. I have removed and checked both drain hoses and they are clear, but on pushing wire up the male drain stub at the bottom of the AC unit the wire stops dead an inch or so in - coinciding with where the drain joins the base of the unit. Does anyone know if I can force the wire up further, or will I hit / damage something important ? Looking at the service manual, the evaporator unit should be well out of the way, so I think I just have a hard accumulation of sludge. My hands are too big to get into the unit via the blower hose inlets when I remove the plastic blue blower hoses, so I can't investigate that way!

The car is a '96 Celebration.

Thanks in advance

Steve

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poprivet

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AC drains - blockage in AC unit?

Postby poprivet » Mon Jul 13, 2009 8:24 am

Hello Steve and welcome.

There is a steel baffle which is what you will be hitting. Poking won't help as it will only push the rubbish up not out.
When you have the blue hose off, the plastic stubs can be twisted off like a bayonet fitting. You should then be able to see inside to clean it out. Likely paint flakes and foam seal debris causing the blockage.
Its not easy access as you have found out.
1988 3.6 XJ-S coupe
'Remember that the value of your investment can plummet as well as fall'

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SteveB
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AC drains - blockage in AC unit?

Postby SteveB » Mon Jul 13, 2009 9:03 pm

Pop

Thanks for the advice - will give it a go - and thanks for your Sept 2007 tech tip with pictures, which was a great help when I first had the problem.

Cheers

Steve

Brakebuster
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AC drains - blockage in AC unit?

Postby Brakebuster » Mon Jul 13, 2009 10:39 pm

can i ask a really silly question

why would the AC drains be overflowing from the rain ?

from what i know ( which isnt actually that much ) the ac has its own drainage, and isnt connected to any body drainage from rainwater on the roof etc ? the ac drainage catches condensation from the cooling coils( heat exchanger ) for the aircon, this has to collect and drain away,

what i do know is that the air intake below the windscreen can get filled with debris, and block the two large drains that flow into the engine bay , with these drains blocked the well under the wiper motor fils to the point of the water wanting to overflow into the air inlet chambers for the fan ventilation

this can be exaggerated if the car is parked facing up a slope, or to one side, ....

the other usual cause is a broken windscreen seal from corrosion etc, as the chrome on the corners is actually a drain away for the roof, these also get blocked forcing water of the the high mark of draining away


just my opinion, but you might be looking for the wrong type of leak.....?

BB
1989 5.3ltr V12 XJS Coupé FULLY RESTORED
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1994 3.2S XJ40 in Morocco Red with Doeskin interior

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almcl
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AC drains - blockage in AC unit?

Postby almcl » Tue Jul 14, 2009 11:52 am

BB

Follow your reasoning and agree

BUT

I find when using the car in humid conditions (especially if warm as well) the volume of condensation, as evidenced by the puddles that form underneath when parked, is much greater.

During the rainy season with humidity up around 90 - 100% the rather inadequate drains on the Delanair Mk III get overwhelmed, even when they are not totally blocked.
Al McL
'93 XJS 4.0 - '05 X type Est 2.0D - '13 XF 2.2D Sportbrake

Brakebuster
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AC drains - blockage in AC unit?

Postby Brakebuster » Tue Jul 14, 2009 12:37 pm

very tru....

i actually work in a large mainframe computer building, and our constant battle with humidity is never ending, especially on warm wet days, and the bloody condensate drains are always getting blocked,

i think what i was trying to say was not to just focus on the drains for the AC, but consider other posabilaties , especially after the downpours we have had


either that or drill a gert big hole in the floor, lol


BB :wink:
1989 5.3ltr V12 XJS Coupé FULLY RESTORED
2004 2.1V6 X-Type Saloon in platinum silver for the good wife
1994 3.2S XJ40 in Morocco Red with Doeskin interior

used to have
1999 4ltr Sovereign XJ8 in Seafrost

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SteveB
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AC drains - blockage in AC unit?

Postby SteveB » Sat Jul 18, 2009 1:24 pm

Thanks guys - cleared the AC unit (some gunk, but not too bad) - drains down the side of the windscreen both clear, as were the plenum drains - but I have found a leak around the base of the windscreen, drivers side, so will get that sorted at the August service - the joys of XJS ownership! Suspect the AC unit just got overwhelmed in the downpours..

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SteveB
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Re: AC drains - blockage in AC unit?

Postby SteveB » Thu Dec 29, 2011 12:21 pm

Thought I would add a postscript to this post for any future readers...

I fixed my original probelm by cleaning out the AC unit AND getting the windscreen re-sealed - only to find I had wet feet again a couple of weeks ago - this time it was due to the AC drain hose getting dislodged when I had a new radio fitted over the summer!
2015 3.0 V6S F-Type Coupe
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Patfallon
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Re: AC drains - blockage in AC unit?

Postby Patfallon » Fri Dec 30, 2011 3:55 pm

Hi,
my experience, though with a 1988 convertible was similar. Occasional wet feet with no obvious cause. Cleared the AC and checked the windscreen wiper motor void and pipes. Wet feet sometimes with and without the rain. Final cure came when I had the screen replaced because of a crack. The sealant wasn't bonded all the way around; there were gaps in places. Surprisingly there was no rusting and the paint was good all the way around. This was the first time the screen had been out since manufacture and it would appear to have always been like it.


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