Key question is this: can/should the evaporator be flushed while in the car, particularly while using the existing, hard liquid lines hooked up to the firewall-mounted expansion valve?

I’m flushing with one of those cheap tank kits, specifically with an air compressor connected to a shop air drier-filter (disposable inline kind) and using Four Seasons Super Flush (solvent based) along with a vacuum pump and manifold gauge set to recharge 2x12oz cans of R134a after adding 4oz PAG 46 (planning on putting 3 in compressor, 1 in condenser). I can’t get new hard liquid lines and don’t want to remove the evaporator if at all possible (lots of dash work)

The full context: The car is my 2015 Kia K900 (5.0L NA V8), quite the upgrade from my 2012 VW Passat (2.5 NA I-5), both in enjoyment and maintenance LOL. Other than the parking brake module needing to be cut out & this A/C issue, it’s been great to me since I got it in fall of 22. Bought at 74k mi, now sits just shy of 120k. It’s a nice eight speed automatic transmission. Zero OBD codes to be had throughout this process.

Last summer, A/C cooling was weakening; by August it was only sporadic, light cooling effect if any. I foolishly added freon from one of those “A/C Pro Smart Gauge” $60 cans, about a third of it until the pressure “read correctly” (I know now) and it worked well enough till this spring where I found it had no cooling effect again.

This time I got to Googling and learned I should never have touched that can… had a shop evac it (they found only 12oz of the 23oz design), I vacuumed it down, charged it fully, and felt a glimmer of hope for 30sec or so of cooling, but then back to nothing. And although I had the parts for it at this point, I hadn’t replaced the receiver-drier or expansion valve as they were harder to access than expected and the system hadn’t been open to air yet to my knowledge, heavily vacuumed & dye tested just fine.

So now I take it to a mechanic two weeks ago who fully diagnoses it, says compressor failure. They went into a rabbit hole about this type of comp, a Doowan DVE18. It’s a clutchless type that always spins the pulley face and simply adjusts the compressing displacement internally via a “variable swash plate”. Brilliantly, it can’t really be inspected or rebuilt except for gauge pressures which kept reading correct, low & hi.

So I took their diagnosis and $1,381 estimate and just had them evacuate it again for me, paid the $150 diag and ordered a $259 OE new compressor. Found a suction hose for $20. Now obviously this time I’d actually install the new receiver dryer & expansion valve but I still hoped to not remove the condenser. Fast forward to this past Fri 1am, still hadriving a highway 30min from home and hear an terrible clanging echo as I get along a divider. Hadn’t touched the engine bay since the shop had it.

I immediately exit and am horrified by what sounds like tapping from timing. Chain looks fine from the oil fill, belt spinning normally, no dash lights or temp changes. Didn’t even think about the AC. Oil was at the L mark so I put a tad in but no change in the horrible noise it made. Limped it home and went to YouTube.

My engine is a GDI, it has 2 high pressure fuel pumps (one on each bank) on the top rear of the valve covers. Big metal machine punk looking things covered in foam with a low (in) and high (out) pressure fuel line, an electrical connector to control output levels, and it’s powered by a “tippet rocker” that is pushed up by a camshaft lobe. All videos of these GDI tippets failing sounded just like my engine, and I could picture the failed rockers that people posted, and how I was maybe hearing my HPFPs chewing through that cam lobe. Uh oh

So I immediately ordered the rockers, seals, fuel line wrenches, etc and beg to worry about reusing the 2000psi high pressure line that the shop manual says definitely not to (I did, it was fine) or fuel spray causing a fire, but I did the repair and even made a little video for it, but no dice, still had the clanging. At this great timing I realize it’s moreso from the front of the engine than top/rear where the HPFPs are. Now I’m thinking timing chains or tensioner, water/oil pump, etc. but those all have so many sensors on em they’d throw a code if there was an issue

Then I notice the suction hose is rattling along with the noise unlike any other part of the engine, then I see the glitter on the subframe exclusively by the compressor, then it clicks. I was still able to spin the compressor freely by hand though, no noises, and certain the shop evacuated it for me. So I had some doubts but drove it to a flat spot and before I even lifted it, just removing the belt exposed a blind spot. The top side of the compressor completely blew out, like through the lengthwise mounting bolt. No wonder I can no longer draw a vacuum… I’ll attach a pic here once I get it removed. It’s gnarly. Glitter all down the discharge line of course, no idea about condenser yet but I’m honestly excited to see inside the drier bay.

So now I’m ordering a whole new condenser with its receiver drier, discharge hose as well, which leaves me with a whole new system except for the hard metal lines for liquid freon between the expansion valve and compressor, and the evaporator buried in the dash. I can get the evaporator for $100 just would rather not rip the dash apart, but can’t get the hard lines anywhere- even used. Custom fab would be money I can’t add to the repair right now.

I can’t help but feel deja vu to my “less work” mindset at the get go, either in adding even part of a can blindly or in not doing the drier and valve. So I don’t want to oversimplify this flush and make it all a waste again, but I figure it does make sense that you can flush the lines and evap as it sits, vacuum for an hour, put in the new valve and connect the rest of the new system, vacuum that for an hour, charge & go. I also figure this assures me I’m getting any PAG oil out of the hard lines and condenser so my total weight added would be exactly correct. 

Just hoping if I’ve got this wrong, i.e. need to remove the lines and flush separately or can’t flush evap while connected, I’d love to hear it now and not after I do it and recharge 🙂 I’ve also seen some guidance saying not to bother even if there’s debris at the valve screen, but mine doesn’t have a valve screen and is worse than any other compressor failure example I’d seen. That it ran “engaged” for so long before it blew up makes me think metal might as well be everywhere but I guess I’ll see from the drier and old valve. Sorry for the wall of text but figure the full context and history might help, or at least lend a laugh. Thanks for the insights!!