Orifice Tube Install

[DavidProehl]

This should be super easy, for some reason it isn't.

I'm wrapping up my install of a new evaporator, and I'm installing the orifice tube (probably should have done this before the evaporator was in the car). I used 134a a/c oil to lube up the inside of the tube and the OT, but it was taking a serious amount of force to go in, and it didn't go in more than half way. Eventually, I broke the OT with the force I was applying before getting it all the way inserted.

Luckily, I happen to have another OT on hand, but I'd be interested in some pointers on getting it in there. I'm putting it in the smaller of the two pipes, and in the direction shown in the below photo.



From reading this thread, it sounds like it should just slide in. What am I doing wrong?

[Bitsyncmaster]

I can't see your photo at work (office will not access the photo sites) but the OT should slide in without to much force. Make sure your tube on the evaporator is not bent where the OT installs into. The short side goes into the hose coupling so really as long as you can start the treads.....that will push it in the correct amount.

FYI:
OT tubes come in two types and many sizes. The type change is just where they put the finger to pull the tube with. One type goes into the hose and the other type into the metal tube. Many systems put the OT into the hose end at the output of the condensor.

[DavidProehl]

So are you saying it is ok if the OT isn't in the evaporator tube all the way as long as I can screw on the metal hose that connects to the evaporator? I may be able to do that much. I'll give it a try.

[WelmoedJ]

If you're putting the orifice in the way it is taped to the pipe, it's the wrong way.
The conical end should go in first (into the pipe), the square eye should be pointing towards the dryer (accumulator).

[Bitsyncmaster]

If you're putting the orifice in the way it is taped to the pipe, it's the wrong way.
The conical end should go in first (into the pipe), the square eye should be pointing towards the dryer (accumulator).

I think your wrong but the OT is just a tube so it works either way. That square end is what you pull it out with.

[WelmoedJ]

I think your wrong but the OT is just a tube so it works either way. That square end is what you pull it out with.

You're right about the pulling.
However as the OT has to be put into the pipe, my afore statement sticks.
I've assisted in the replacement of a couple of OTs in several D's and the way I described it, has been the way we did it.

[dmc6960]

The orientation in the original picture is correct...

[Ron]

Look on the orifice tube there is usually a small arrow pointing in the direction of flow. You cannot go by the tab or tabs to pull one because some go in the condenser pipe and others go in the evaporator pipe, like a De Lorean. The tubes are sometimes tapered too! If no arrow, the answer is that the larger screen ALWAYS filters incoming refrigerant. The smaller screen is a backup (for if/when the large one bursts).
So the orientation in the photo is correct.

If you can't get it to go in and you are 100% certain you have the right size diameter OT, usually the tube is defective, twisted or otherwise abused. Since this one is new and it goes in part way, I would suspect the former more-so. In any event, I would try this. DO so at your own risk ;-) :
Remove the O-Ring and see if the OT will go in easily all the way, If so try the O-ring if it is not hard etc. If not, you can take a tapered rod and gently tap it into the tube while FIRMLY holding the tube BEHIND THE CRIMP -- DO NOT allow the tapping force to travel the tube or you may cause the evaporator to leak! You must be certain not to use a rod that is too big else you will be screwed looking for a OT to fit.

[dmc6960]

Check if there is any curve in the evaporator pipe where the orifice tube goes. If there is any kind of bend at all, it will make it extremely difficult to install the orifice tube, just like you have experienced. Try straitening it out.

If it already is completely strait, try more oil.

[Ron]

I think there is an echo in here Jim. LOL