Thread: Adding Air Con - Bulkhead Install (TD,TDI,?)

I am wanting to do the same with my D90 here in the USA!
Do you know what the difference is between the MUC1663 and the AWR1168 are?
The parts book says one is non CFC free (the MUC)
Huge difference in price too.
Was wondering why you chose that one over the other?
I do want to have it recirculate though and really dont need outside air at all. I have vents for that.

Thanks and I look forward to your progress.

Originally Posted by RovinC

I am wanting to do the same with my D90 here in the USA!
Do you know what the difference is between the MUC1663 and the AWR1168 are?
The parts book says one is non CFC free (the MUC)
Huge difference in price too.
Was wondering why you chose that one over the other?
I do want to have it recirculate though and really dont need outside air at all. I have vents for that.

Thanks and I look forward to your progress.

In microcat they appear to be the same thing, share all the same part numbers apart from maybe the evaporator core

Why the MUC1663 evaporator core would need CFC refrigerant is beyond me? What happens to it if it doesn't get CFC's? I have no idea if mine has a MUC or AWR evaporator.

What is curious - I cant find the evaporator core part number. I thought it was shown in micro cat but turns out the diagram points to the expansion valve and a pipe, not the actual core. Surely it can be replaced - and has a part number?

Well they seem to be 2 different units.
The AWR came in the NAS Defender 110's and here are a couple of photos.
The casing looks totally different that yours.
So I am wondering what the interior looks like then?
They must have changed something?
However the AWR also costs 4x what the MUC unit does as well.

Originally Posted by RovinC

Well they seem to be 2 different units.
The AWR came in the NAS Defender 110's and here are a couple of photos.
The casing looks totally different that yours.
So I am wondering what the interior looks like then?
They must have changed something?
However the AWR also costs 4x what the MUC unit does as well.

Thanks for the photos - I've not seen that unit before. I was only going on microcat which used the same image for both part numbers and a website that had pretty much the same internal parts list for both units. So yes I suppose different units or maybe there its only the LHD AWR that looks different

I didnt think about LHD, RHD installs. If you are looking to fit it on the right hand side of the bulkhead you may have to use the NAS spec unit - the MUC1663 I have would not mount in the position shown in your photos.

I found this pic on MC and it shows a part number for the evap of RTC7436, though the photo is very different than in the MUC one.

It doesnt seem to specify on either the MUC or AWR units LHD or RHD.
I also cam across more part numbers for similar units, so maybe they are superceded by others?

Id really like to see the 2 units side by side and internally.

Done a few things since last update.

Intake for the MUC has smaller opening under the wing top vent, so the top vent cover will not fit with its protruding fins. I had to snip off some of the fins with a tile cutter.





Put some neoprene stick on seals from clark rubber for bulkhead and side intake ducts.







I won't need the rover till end of March so a few bolts and the wing is off, perks of the defender!



I now have better access to drill the mounting holes for the MUC, I can also get better access to the dipstick, dump pipe and clutch/brake hoses which all need to be tinkered with for this install.

My clutch and brake pipes are running across the top face of the footwell and in the way of where the MUC will sit, so these need to be bent out of the way and properly secured. They have already been bent about to fit around the disco 200tdi conversion turbo dump. The dump pipe comes off to be heat wrapped seeing as it will be sitting directly under the MUC




Added some heat/sound insulation to the foot well whilst it is clear and accessible.



The MUC runs air through the air con evap or heater core depending on position of an internal flap but when the air con is running having the heater core hot in the box is not going to help. On county land rovers the core is bypassed with a vacuum solenoid and switch. I cant be bothered with all that so I got one of these:



Its a Puma ford transit heater bypass solenoid that opens or closes the flow of coolant to the heater core given a 12v feed. The pipe diameters are the same as the defender heater and MUC. They are very common and cheap to buy new but the cheapy ones are known to fail! When they fail they stick in the on or off position but because they are cheap and it will take 30 seconds to replace I wouldn't be too bothered even if it failed after a year - so I'll give this cheapy one a chance.

Now I'm trying to figure out how to switch the solenoid on and off from the cabin. The aim of this install is to change the interior as little as possible so I'm looking at using the existing hot and cold mix lever to trigger the solenoid.



One lever actuates the flap in the defender heater box and the other the direction air flap behind the dash for air to windows or down to feet.

The MUC also has a flap for diverting air to hot or cold paths so the cable actuation from the hot cold lever can be hooked right up to the MUC flap no problems there. But for the heater matrix bypass solenoid I would like to add a switch on the mix lever. When I pull the lever past the middle towards the hot setting I want to activate the heater matrix solenoid to turn the heater core on and when moved over towards the cold half the solenoid will deactivate and bypass the matrix. So with the switch in place the top half of the levers motion will mix outside temp air with a cold aircon matrix and the bottom part will mix outside air temp with a hot heater matrix. Of course at each extreme of the lever you get 100% heated air or 100% AC evap cooled air (or outside temp air depending if AC is switched on or not). For activating the AC I will use a carling switch on the center console.

Here's my first idea to add a switch to the lever. Other ideas welcome!



Apart from that I had to remove the exhaust and inlet manifold to get the disptick out which I need to bend away from MUC occupied space. With the dipstick out I've figured out the bends required but kinked it in the process, so waiting for a new defender 200tdi stick and tube and a cheap pipe bender tool. The new bends will also allow the dipstick tube to be removed from the sump without having to remove the exhaust manifold - a bonus!

Be aware that your engine needs the coolant bypass system for when the thermostat is closed. If you block the bypass through the heater, the water pump won't be able to circulate coolant through the engine until the thermostat opens and you risk having hot spots and vapour locks in the engine.

The Tdi engines don't have a separate bypass (silly, I know, for those in warmer climates than the UK) , Land Rover chose to use the heater circuit instead of a bypass (as was there normal practice). I don't know about puma's, since they are a Ford engine they may have an external bypass, so it is ok to block the heater flow.

If you want to close the heater flow, you will need to Tee a bypass hose in around the heater.

Yes I thought it would need to maintain a flow of coolant. You cant see it clearly in the picture but the unit has a bypass pipe across the middle, so the pipes combine in a H layout. When the solenoid is activated it closes only the entry to the matrix, the coolant can still flow across the bypass pipe. The exit from the matrix is always open but when the matrix input is shut off the hot coolant will run past the matrix outlet as there is no path through the matrix. Heat transfer down the matrix outlet to the cold coolant in the matrix shouldn't occur because heat rises and the coolant in the matrix sits below in in/out pipes. So this unit should do the job.