AC Expanison Valve screen

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
To the "old school" crowd or late comers familiar with R-12 Systems... (Now an R-134a system)

I made the stupid decision two years ago to put "stop leak" in my 84 Vanagon AC system (ALH Engine with Jetta OE Compressor). Well, it keeps plugging the screen in the Expansion Valve. I've cleaned it once (last summer) and it is now plugged again. I did some connector repairs at the AC Compressor, new dryer, etc. Right off, the compressor pulled a vacuum on the Low Side and high pressure on the High Side with less than a can of R134a.

So, I removed the Expansion valve to find the screen plugged again.

Question, would it hurt to leave screen out?

We were hoping to hit the road Saturday morning on a 30 day journey ... this issue (and a couple of others) has set me back at least two days..
 
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AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
Well, I got an answer via a PM response.

Seems there is not a function issue with respect to the Expansion Valve doing its job (compressed liquid to a gas) if the screen is left out. However, without the screen, junk will end up in the evaporator. I'm not sure that would hurt anyway since the junk come from the compressor, hoses, condenser, etc.... guess it would just keep circulating.

So, I'm leaving the screen out........... a plugged expansion valve is a dead expansion valve, is how I see it! Maybe by next summer, I can replace all those 33 year old hoses and flush the system!

See you on the road....
 

tadawson

Veteran Member
Joined
Jun 14, 2013
Location
Lewisville, TX
TDI
2013 Passat TDI SEL, 2015 Passat TDI SEL
Have you tried to flush the system? May or may not help, since you can't really flush a compressor, but should get most of the rest. Also, no all stop lrak products are solids/particulates - IE some can actually work, but you need to choose carefully, and as noted, none are as good as an actual repair.

(Sorry, just reread that you did not flush . . . nothing preventing that even with the old hoses, though . . . just more work, but if the syste is open, you are most of the way there anyhow.)
 
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compu_85

Gadget Guy
Joined
Sep 29, 2003
Location
La Conner, WA
TDI
... None :S
Ya, I'd say it's time to completely flush the system. I'd rather replace a screen at the TX valve than have to try and un-gunk the evaporator. The evaporator is probably parallel flow, so it might not be able to be flushed!

-J
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
Well, the system has been somewhat flushed going back to 2012 when I first converted it to R-134a. As I stated, its pushed by the Jetta compressor with the Refrigerant Control Valve (RCV) removed and replaced with a big bolt and nut. With the RCV removed, the compressor operates is very similar to the OE for the Vanagon.

Below is a pic of the RCV ....



Below is a shot of the bolt replacing the RCV...



And, below going back together you can see the bolt and nut in place of the RCV.



This set-up worked fine in the summer of 2012, 13, & 14. Then, a leak developed at one of the "adapters" (welded mod to mate the two systems) resulting in a loss of refrigerant. So, being lazy, I vacuumed the system, charged it and added some stop leak. Before that summer (2015) was over, the screen was plugged in the TXV (Thermal Expansion Valve). I removed it for cleaning ........ plugged really bad with a glue-like substance which I assume was the Stop Leak junk.

Fast forward to late spring 2016, I removed and cleaned the screen before heading out on a 30 day road trip............. worked fine until about the last 4 or 5 days. Until about two weeks ago, the Van hasn't been driven over 1500 miles since last August.

So, again two weeks ago, I find the TXV screen plugged (high side pressure too high and low side almost at a vacuum). I removed the TXV and cleaned it. I also disassembled the AC Compressor for inspection (have an extra if needed). It basically looked the same inside as it did 5 years ago. I did drain and add 3 oz of PAG 100 oil. I also added about 2 oz of oil to the system. (I had it off to replace the pulley bearing....... so, was already there is why I did the inspection.)

Below is a photo of the AC Compressor 5 years ago.... (FWIW, I reused those gaskets without any leaks ... stay nice and clean.



Checking all the fittings, etc., 5 years ago and again this week as well as having a section of hose cut out and spliced (due a hole caused by rubbing on the chassis), the hose looked really nice inside. (I did flush the evaporator 5 years ago.).

Anyway, I vacuumed it down to about 29 inches and it held overnight. I charged it today with slightly over 2 cans of R-134a... seems to be working okay.

I do agree! Those 33 year old Uniroyal hoses are past due to be changed out.
 
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compu_85

Gadget Guy
Joined
Sep 29, 2003
Location
La Conner, WA
TDI
... None :S
I always wondered why you removed the control valve. It should work great with it - the clutch simply won't need to cycle.

-J
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
Well, Compu_85, someone back in 2012 put me on a link with a story about removing the RCV due to it not working with the old style TXV. That is the only reason I done it. A year or two later, someone told me that the system would work just fine with it.

The down side is, the smaller electric clutch on the TDI compressor cannot handle kicking in if the pressure has not pretty much equalized. So, I just turn the temp setting to max until the vehicle cools down then back it off until the compressor kicks-out (light in dash comes on when the compressor kicks-in)

So, maybe I should have re-installed the RCV last week when I had the compressor apart for inspection.

..............
Okay, I took it for more than a 20 mile ride this evening.

Outside ambient temp > 75.6f (the ambient today was 86f when I charged the system)
Temp coming out of vent > 41.6f

Once the Van cooled off, I turned the temp control down until the compressor kicked-out and then turned it down a bit more. When the temp of the air went up to a little above 52f the compressor kicked-in. Then when the temp got down just above 44f the compressor kicked-out. I observed this cycling for about 14 miles or more.

So, I think it is fixed for now......

Side note: If I had not got the flu back in late February, which put me down for almost two months, I'd addressed the AC much sooner! (tough getting old)..
 
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jmodge

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Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
One of the leadmen I work with spent over 20 years at Reefer Services, (refridgerent, not medical marijuana). I remember him telling me to use oil and hoses specific to the refridgerant used, can cuase hose deterioration. The expansion valve had some "flashing" purpose.
He is quite sharp, having done service calls on reefer trucks for most of that time. If you want me to throw a question at him let me know. You may have to PM me for me to notice.
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
Well, the AC system worked great ........... until the high pressure hose ruptured.

We were on our way to Alaska and just south of Indianapolis the hose gave up. So, we did a 180 and returned home. I'm now working on a 10 day window that will close Saturday. However, if I get it repaired and going, we will extend the departure to Monday, July 24th.

Right now, via internet, I am working with coldhose.com. Using my measurements, photos, etc., they are making up a set of new hoses, both pressure and suction sides with new fittings, ports and adaptors to the Sanden SD7V16 Compressor on the TDI engine.

Mean while, I've removed everything for flushing.....
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
Pm'd you, will get back when I have some info. I think I remember Bill telling me the R12 hoses would eventually give out. I have r12 in my k5 and had considered changing to r34
 

tadawson

Veteran Member
Joined
Jun 14, 2013
Location
Lewisville, TX
TDI
2013 Passat TDI SEL, 2015 Passat TDI SEL
About the only issue I know of with R12 hose vs R134 is that the older hose is not barrier hose (dual layer) and the R134 molecules will slowly be lost through it. A far bigger issue in changing refrigerants is oil compatibility, since some mismatch so poorly they become very acidic . . .
 

jmodge

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Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
About the only issue I know of with R12 hose vs R134 is that the older hose is not barrier hose (dual layer) and the R134 molecules will slowly be lost through it. A far bigger issue in changing refrigerants is oil compatibility, since some mismatch so poorly they become very acidic . . .
Exactly, first a little info on r12 to r34 swap. An 80% charge rather than full charge unless you changed hoses. Removing ALL mineral based oil from the system. They used r11 that changed to liquid at atmospheric pressure.

But, in the end, the ester based oil from r34 will break down the r12 hoses.

So, I assume you are getting hoses that are r34 compatible?

Bill said brakleen can be used to clean the compressor, but most likely air pressure may be your only alternative to cleaning the rest.

The orifice serves two purposes, catching contaminents and flashing the refridgerant to aid in converting it from gas to liquid on it's way from the condenser to the evaporator

Hope this helps
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
As a side note here, if anyone should per chance locate some r11, DO NOT OPEN IT IN AN ENCLOSED ROOM. It turns from gas to liquid at atmospheric pressure.
So when you open it, the oxygen in the surrounding air will be absorbed. It could drop you quite fast.
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
Well, I've ordered both long hoses for the Vanagon that will mate to the "adpators" for the Sanden SD7V16 Compressor that's on my TDI engine. Coldhose.com has a good on-line "custom build" work page as well as lots of other good info and all the parts you'll ever need.

Okay, maybe I'm going about this the wrong way, but I'm doing a triple flush. First, I'm using Mineral Spirits to breakup the oil and any chunks of debris that may be clinging to the inside of the evaporator, condenser, etc. Then, I'm following with two blow-throws of Acetone! Acetone will flush-out the Mineral Spirits and any left-over residue of AC oil(s). Acetone is good about absorbing moisture and evaporates really fast.

I just finished flushing the Evaporator. I captured the blow-out stuff ......... (no debris) nothing but a reddish color liquid (AC oil, Mineral Spirits and Acetone). The last blow-though was clear Acetone!

I'm going to tackle the Condenser without removing it from the vehicle. It appears the loops all weave down to the bottom. Thus, it should blow-out nice.

Then, I'll do the two short high pressure hoses (from bottom of Condenser to Dryer and Dryer to Expansion Valve/Evaporator).

The new hoses should not need a flush (they are R-134a compatible).

I'll flush the Compressor again as well.

Side note: Has anyone read about "adjusting" the expansion valve? It is adjustable!
 
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jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
Does "adjustable" mean it adjusts itself as it captures debris?
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
No! On the outlet side of the expansion valve, inside, there is a screw-down "inside" nut with an Allen head fitting. It can be screwed up or down. It applies pressure to a spring which sits on an orifice with three long tiny stainless steel rods. If you crank it down the orifice opening becomes smaller and smaller. When cleaning it, I counted the number of turns on the nut to determine where to put it back (that was almost two weeks ago). Before the high pressure hose burst, it cooled about as good as it ever has...... and the ambient temp was pushing 100f.

The screen is pre-orifice...... Thus, if the screen gets plugged, no cooling at all. In fact, the high side pressure goes way up and the low side can actually show a vacuum, depending on how tight the screen is plugged ......... been there and seen that many times with all my Vans, Rabbits, etc.

Okay, I've flushed everything. The condenser was really loaded with crud. I ran three canisters of Mineral Spirits through it. Then, I followed with the diluted Acetone/Mineral Spirit (filtered) mix that I caught from flushing the other components.... three passes of that stuff. Then, I flushed with three canisters (over a quart each) of straight Acetone. The last one come out almost clear.

So, I'm satisfied everything is flushed thoroughly.
 
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03TDICommuter

Veteran Member
Joined
Dec 8, 2016
Location
So. Cal
TDI
01' NB, 5spd
Sorry for not knowing - what construction style is the condenser? I hear that parallel flow is impossible to flush. You might have to replace it.
 

compu_85

Gadget Guy
Joined
Sep 29, 2003
Location
La Conner, WA
TDI
... None :S
Being that the van was originally R12, I imagine it is a "standard" tube and fin condenser - and possible to clean out.

-J
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
Andy, check the manual for procedure for setting MOP, Max Operating Pressure
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
Yeah, Compu_85, it has an OE Vanagon system ....... all fairly large tubes in both the condenser and the evaporator!

Jmodge, back in May when I splice-patched and charged-up the system, I actually put in two cans of R-134a which soared the pressure near 225 psi on the high side at 85f ambient with a box fan blowing on the condenser. That's far more than I've put in it in the past, generally about 1.75 cans. So, I guess that, in part, is why the splice blew out.

The hose blew at a rest stop south of Indianapolis. We left the Van running while stopped. The ambient temp must have been pushing 100f. So, I suspect the pressure really soared those few minutes we were there.

Considering the hoses are 33 years old, they've done pretty good. However, I should have addressed the AC stuff long ago!
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
Besides replacing the AC hoses on my Vanagon, I'm also replacing the fabricated adaptors on the Compressor.

In the pic below, on the right are the fabbed adaptors. I cut the thread part off the OE Vanagon Compressor and had them welded to the OE adaptors on the Sanden Compressor that come on the ALH engine. The two metals are not compatible and the welds left "craters" that were prone to leak refrigerant. On the work bench, I vacuumed JB Weld into the craters. That worked okay.

The OE hose is AN #10 but has #12 fittings. The new hose is #10 with #10 fittings on the suction side and #8 on the pressure side.



Below, is the Expansion Valve partially disassembled. You can see the end of the Allen wrench to the far right next to the internal nut that screws down on the spring. As I mentioned in a previous post, it is my understanding that the Valve can be adjusted based on the pressure put on the spring (Example, number of turns off the bottom or number of turns down from the top). I plan to leave it as is. The valve is R-134a compatible. (The cone shaped screen can be seen below the capillary tube.)

 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
When I had one of my old Toyota's with a similar problem, I installed one of these:

http://www.autozone.com/cooling-hea...sept-a-c-inline-filter-kit/112569_17299_10460

It eventually caught all the crap, just had to R&R and clean it out once in a while, but the frequency got less and less.

Don't worry about hose deterioration with R134a, the type Volkswagen used seem to hold up fine. I've converted every R12 Volkswagen I ever owned after about 1995 to R134a. Heck, my 1991 Jetta has been R134a longer than it was R12. Of course, your van is older, so maybe they did not use the barrier type back then, not sure. I converted my '87 Vanagons (2 of them) and never had any issues during the time I owned them.

Volkswagen (as well as others) had nice retrofit guides back in the '90s, with items they wanted changed for the best operation. Some were more involved than others.
 
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