Airconditioner evaporator clean

[Intrepid]

G'day,

I have just had my aircon repaired in the 110 and it's the first time I have had it working since owning it. It has the passenger footwell AC setup.

It works, or at least cools, really well, then seems to ice up and restrict airflow. I turn it off and after a couple of minutes, it's good to go again. I could also hear some water in the fan at one point yesterday. I blew out the drain, and it seems to be clear?

I read on an older post that you can clean the evaporator in situ, which is my first port of call, in case it's blocked. I had a look at the front of the evaporator through the speaker cavity and it looks clean, though I can't vouch for the fan side of the unit.

How do I get to it? Do I have to remove the ducting fitted to the dash and fan? I had a look the other day and I was having trouble finding the bolts/screws holding ducting to the dash. Any advice would be great!

Thanks.

Joshua

[goingbush]

What model 110 do you have,
below is a pic of the Evaporator I removed from my Td5

There is no way on the planet that you could properley clean this in the car.

The gunk seems to be a sticky concoction holding all manner of particles into a semi solid goop. Surprizing the time its spent in the outback there was no evidence of red dust in the conglomeration

I used a whole can of deagreaser and 10 mins full on spraying with a garden hose and its still not perfect.

https://www.aulro.com/afvb/images/imported/2012/10/763.jpg

I replaced mine with aftermarket A/C ,
by the way above evap is on ebay

.

[Intrepid]

What model 110 do you have,

.

sorry, it's a 1997 110 defender wagon.

I just had a new condensor fitted - all Sanden brand. Ideally I'd be able to strip away enough plastic and the fan to 'blast' the evaporator with water, flush any gunk out. The fan's the biggie.

It works well enough, it just stops gradually. The other part that may need looking at is the thermister, though that sounds more complicated, so easy stuff first :)

Joshua

[rover-56]

I'm no expert but I would look at the evap thermostat setting. It has to be above 0 deg.C or the evap will gradually ice up.
Sounds like what you have.
I will defer to the refrig techs on here.....

Terry

[Intrepid]

Thanks Rover,

I am beginning to think the same. I had most of it sort-of loose and pseudo accessible yesterday. I gave it some with the hose, and nothing much came out.

I put it all together and it's really cold. I think it may be too cold. This with the AC set to the mildest setting and the fan at 2 (out of 3). I'm getting good airflow, so i'm thinking it may not be clogged much, until it freezes over.

I'll give my mechanic a bell, see what he thinks. Thanks so far guys.

Joshua.

[OLD]

Hi Joshua

In April this year, I too had my A/C repaired in my 94 110 defender. After the compressor was replaced, the unit would blow really good cold air - until it froze over. Wasn't real happy about that so like you, I searched through the forum and came up with the prospect of the A/C thermostat being at fault.
Took her in to Morley where it was established that the thermostat was shot. Had it replaced by a A/C specialist in Northbridge for $220 and its been brilliant ever since...:cool:

Martin

[rover-56]

There are two 'thermostats' one is linked to the thermo amp and is the one that responds to the temp adjust knob. the other is the mechanical expansion valve in the refrigeration circuit. This is supposed to keep the evap temp at about +2-4 deg. I don't think it is adjustable so I have no idea how to fix it if it is the problem.
Good luck:)

Terry

[goingbush]

thes pics help explain what Terry is saying,

below is the thermostat / thermistor that was on my Td5 evaporator
if it comes adrift your evap will ice up, its only wedged in there, Ive cabletied my new one to the tube on my new evaporator

https://www.aulro.com/afvb/images/imported/2012/10/682.jpg

https://www.aulro.com/afvb/images/imported/2012/10/683.jpg

I dont know the Tdi A/C but the Td5 used a Mercedes/BMW style expansion valve

https://www.aulro.com/afvb/images/imported/2012/10/684.jpg

And heres the old style Exp valve on my new evaporator, the temp sensor bulb is on the end of the copper tube is under the white insulation wrap

https://www.aulro.com/afvb/images/imported/2012/10/685.jpg

[rover-56]

Thanks Don,
Pics are always better.
The last picture looks more like the AU Tdi valve.
I do know the bulb has to be very well attached to the refrig tubing.
T

[Intrepid]

Great pics. Thanks for that. I had a look at the wires in and around the evaporator and gave them a bit of a jiggle - they seem encased in a black putty of sorts.

The mechanic suggested it was a thermistor problem too, so I'll dig a little deeper when I get a run at things. I suppose it'd be worth checking the thermistor is wedged where it should be first. Access is still an issue in terms of doing it without upsetting the refrigerant, but I'll see what I can do!

Thanks again for the great info. I'll update when I have more info.

Joshua.

[ezyrama]

Make sure the sensor is pushed right into the coil and not sitting on the face, so it can get a decent coil temp reading, If there is a restriction on air flow, that will cause a coil to ice up and so will the unit being short of gas and a restriction in the TX Valve will cause the same problem. bGet some coil air on and air off temps and post them, it will tell me roughly what is going on, but it's a bit hard without knowing gas pressures.
Cheers Ian

[Intrepid]

I hope this will round out this post.

I have attached some pics of this mornings' work.

I put it down to a dodgy thermistor, but I couldn't confirm it, not without resistivity figures for the thermistor. The local guys didn't have any, and I later found out that one I likely needed had been discontinued.

I put the ohm-meter across the wires and got 1.1kOhm resistance in ambient conditions. In a bath of ice water I read 2.8kOhms.

I rang the local electrician and asked if they had any thermistors. They suggested I go to the dump and see if I can get some from some of the old split-system house aircons, which I did. It would have been hit-and-miss buying without knowledge of their resistance curves/tables.

Anyyywayyy... I salvaged 6 of them, tested them all in ambient air and ice water and from there selected the one with the lowest electrical resistance as a test (with the aim of working up until one, if any, sufficed). I hit the jackpot on the first one!! It was reading 3.5kOhm at ambient (32 deg or so) and 9.5kOhm in ice water. Once installed it was cutting the AC on and off at acceptable levels. I have managed, after about 30 minutes of driving, to find that setting the temp dial about half way around works great, though the kids in the back were still complaining they were hot. I think this more a 300tdi issue...

The photos are of the actual new thermistor, just fitted. The one I removed was jammed in the hole visible in the photo. The mechanic advised that it should be mounted on the fascia of the outflow, just as it is now.

The bonus was that the next thermistor to test was very similar to the 1st in resistance, so I'll keep it as a spare.

In the end, I have solved and fixed it with great input from fellow LR enthusiast. Thanks. Cost me $2 in fuel to get to the dump and a bit of time. I hope this helps someone else.

Next task is to improve A/C efficiency in the Landy - Ideas? I'm thinking window tinting and clear blind to cover the cargo barrier?

Catchas,

Joshua.

[ThorneGator]

I found this post while doing a search for more information.....

I am having the same symptoms as Joshua mentioned; icing up, etc.... I know there could be a number of causes, but to start crossing them off could anyone walk me through accessing the evaporator on my 110 (2005/ TD5)? It has never been removed and cleaned before, so would be confident that it would benefit from a good cleaning.

Thank you in advance