Removing rear AC

Mr.SA · Post by **Mr.SA** » Mon Jul 24, 2017 5:27 pm

I'm planning on removing my rear AC/heater, i never use it, and it doesnt really work as is. But i definitely want to keep the front. I've never messed with anything AC related before so just looking for a quick rundown on what I need to do for venting/blocking off hoses etc..

I know I need to get an AC shop to vent the AC, though id guess mine's empty as is. but if its simply vented, do i still need to worry about leaking anything?

Is the front and rear AC connected? If so should I block off the AC lines up front vs in the rear?

And for the rear heater, I'm not sure how its plumbed, but i'm guessing its connected to the front heater/coolant? so cant just cut and drain those lines as i'll be draining the engine coolant?

and if it is connected to the front, should I just run hose from the inlet/outlet tubing to keep the coolant circulating? any positive or negative to looping it back towards the rear AC? or should I aim to loop it towards the front?

Post by **Growlerbearnz** » Mon Jul 24, 2017 6:28 pm

The front and rear AC systems are in parallel, so you can just disconnect them and plug the pipes (both refrigerant and heater pipes). No need to loop the lines together to keep the coolant or refrigerant circulating.

An AC shop should be able to cut the rear refrigerant lines and seal them shut, but you might have to get creative with the coolant lines.

tomaboyd · Post by **tomaboyd** » Tue Jul 25, 2017 8:10 am

There are a couple good detailed posts out there describing the process. Here is one.

http://www.mdocuk.co.uk/forums/viewtopic.php?t=37185

I was thinking of doing the same thing but have held off. The rear AC and heat is all in the same unit. When you remove the AC you loose rear heat as well.

You could still remove lots of the other bits. Compressor, AC radiator etc., but one of the biggest things I was looking for was that nice big space that the rear AC/Heat unit occupies. That would be a nice space to relocate the Trans Radiator.

I think ultimately I will remove the rear and put in a propex heater as a replacement, just not ready to do that yet.

Mr.SA · Post by **Mr.SA** » Tue Jul 25, 2017 10:46 am

Growlerbearnz wrote:The front and rear AC systems are in parallel, so you can just disconnect them and plug the pipes (both refrigerant and heater pipes). No need to loop the lines together to keep the coolant or refrigerant circulating.

An AC shop should be able to cut the rear refrigerant lines and seal them shut, but you might have to get creative with the coolant lines.

Ok thanks, I've seen two posts where people made a loop for the rear heater pipes (not sure about refrigerant) so i wasnt sure.

Another question then, so say I cut the heater and refrigerant lines at the rear heater/ac unit and plug them. what happens to the coolant and refrigerant?
will I have lines going back to the rear unit full of coolant and refrigerant that just isnt circulating with the system? im just having a hard time grasping how the front/rear system works.

I was thinking of eventually buying a coolant heater like the espar D5, and i was wondering if I could mount that in place of the rear AC/Heater unit since I'll already have lines running back there. but will that not work with how the system is designed?

Post by **Growlerbearnz** » Tue Jul 25, 2017 3:31 pm

Here's how the AC is plumbed:

: AC.JPG (201.03 KiB) Viewed 2604 times

Once the refrigerant has been cooled by the condensers, it can go to the front AC, rear AC, or icebox. Deleting any one of those units doesn't stop the refrigerant from going through the others.

To avoid having refrigerant which doesn't circulate (good point), I'd trace the rear AC lines back to where they tee off the main circuit and cut them close to the tee (which is, from memory, just in front of the radiator on the left side chassis rail). Though I'd check with an AC shop first to make sure they can seal a hacked-off pipe, you might need to leave them a bit of length to work with.

The heaters are similar:

: Heat.JPG (39.01 KiB) Viewed 2604 times

Though if you're thinking of fitting a heater at the back, you probably want to leave the lines whole. From the diagram you can see that if you just linked the inlet and outlet pipes for the rear heater (without a heater in there) you'd be pumping hot water straight into the engines' cold water inlet. In the link above, you can see they've used a rubber hose to connect the pipes, but it has a nice big kink in it to stop the water circulating.

204explorer · Post by **204explorer** » Tue Jul 25, 2017 5:13 pm

Plugging the heater lines is really easy. I do it all the time at work when i work on coolant systems. I made myself some plugs out of 1/2 , 5/8 and 3/4 inch bolts. I used long bolts that are not fully threaded and cut them off. You just push them into the coolant hose and put a clamp on it.

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Mr.SA · Post by **Mr.SA** » Wed Jul 26, 2017 12:43 pm

Growlerbearnz wrote:Here's how the AC is plumbed:

AC.JPG

Once the refrigerant has been cooled by the condensers, it can go to the front AC, rear AC, or icebox. Deleting any one of those units doesn't stop the refrigerant from going through the others.

To avoid having refrigerant which doesn't circulate (good point), I'd trace the rear AC lines back to where they tee off the main circuit and cut them close to the tee (which is, from memory, just in front of the radiator on the left side chassis rail). Though I'd check with an AC shop first to make sure they can seal a hacked-off pipe, you might need to leave them a bit of length to work with.

The heaters are similar:

Heat.JPG

Though if you're thinking of fitting a heater at the back, you probably want to leave the lines whole. From the diagram you can see that if you just linked the inlet and outlet pipes for the rear heater (without a heater in there) you'd be pumping hot water straight into the engines' cold water inlet. In the link above, you can see they've used a rubber hose to connect the pipes, but it has a nice big kink in it to stop the water circulating.

Thanks thats super helpful! The plumbing for the coolant does make it super tempting to run a coolant heater in place of the rear heater/AC..

204explorer · Post by **204explorer** » Wed Jul 26, 2017 9:20 pm

Mr.SA wrote:
Growlerbearnz wrote:Here's how the AC is plumbed:

AC.JPG

Once the refrigerant has been cooled by the condensers, it can go to the front AC, rear AC, or icebox. Deleting any one of those units doesn't stop the refrigerant from going through the others.

To avoid having refrigerant which doesn't circulate (good point), I'd trace the rear AC lines back to where they tee off the main circuit and cut them close to the tee (which is, from memory, just in front of the radiator on the left side chassis rail). Though I'd check with an AC shop first to make sure they can seal a hacked-off pipe, you might need to leave them a bit of length to work with.

The heaters are similar:

Heat.JPG

Though if you're thinking of fitting a heater at the back, you probably want to leave the lines whole. From the diagram you can see that if you just linked the inlet and outlet pipes for the rear heater (without a heater in there) you'd be pumping hot water straight into the engines' cold water inlet. In the link above, you can see they've used a rubber hose to connect the pipes, but it has a nice big kink in it to stop the water circulating.
Thanks thats super helpful! The plumbing for the coolant does make it super tempting to run a coolant heater in place of the rear heater/AC..

I posted a write up when i installed my espar d5 on my L400 last winter. Not sure how to send you a link to it.

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Post by **Growlerbearnz** » Wed Jul 26, 2017 10:53 pm

So you did. Nice!

http://www.delica.ca/forum/viewtopic.ph ... 1&p=133602

(I just searched for "espar D5" in the search box.)