When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hi all. I'm doing an A/C system (mostly) replacement—replacing compressor, dryer, and condenser. I don't want to replace the evaporator, because as I understand it, you pretty much have to remove the dash and I really don't want to get into that. So I'm just gonna flush the evaporator and all the lines/pipes. Replacing the condenser because my understanding is it can't be flushed.
My question is: how do you flush the evaporator? I've done some research and the only info I've found is quite generic, like "I flushed the evaporator." How? Where did you put your flush gun?
My disassembly so far seems to show a larger pipe connected to the dryer (red circle), and a smaller pipe connected through the orifice tube connection (blue circle), to the condenser.
I assume these two pipes go to the evaporator in the dash, and therefore the flush gun is stuck to one of the pipes? Which pipe do you flush into—the red circle, or the blue circle (or does it not matter)?
Just a few bits of info: "if" there is any refrigerant oil in the evaporator, you will likely blow it out, so you'll have to calculate total oil replaced as if you replaced the evaporator. Flushing can be really messy, so be prepared for that. Once you have flushed, you need to make sure you get all the flush chemical out. Best method is nitrogen, but at least try to use dry air, as in use a water trap in your air compressor hose. Once you have everything reassembled, vacuum longer than usual to get any remaining flush chemical out.
The small diameter pipe leads to the inlet to the evaporator. The large diameter is the outlet from the evaporator. I have read, but do not have personal experience, that you need to remove the intake manifold to actually reach the evaporator inlet/outlet block fitting.
So, this is a job requiring the proper tools and equipment. You might try putting everything back together and taking it to a professional to have it evacuated, charged and leak tested.
I watched this when I flushed my evaporator and lines, also replaced condenser coil and compressor.
It made a mess in the engine bay and the garage stunk from the flush, it was a fake citrus scent (think of some cheap cleaner you get at a dollar store) so not horrible but stayed in garage and engine bay a few days.
Flushed the lines out front and looked with sunlight to see what came out.
Rented the flush gun and bought the flush solvent at Autozone.
A/C working great years later.
Flushed in the line with red circle to go against the normal flow, but just for kicks I flushed the one at orifice tube also, then did it the first way one more time.
I tried holding white rags over the ends to see and catch what came out, then just let it spray out to get full force.
Last edited by 1999corvettels1; Jun 28, 2022 at 05:23 AM.
Flush Evaporator?
