griffiths

First pic of TEV is an oily TEV. Oil could be refrigerant oil.
Clean the TEV well. If you have dye in the system and its refrigerant oil
it will glow under the UV light for sure. Or use an electronic leak detector
while the system is operating.

Second pic, its been a awhile, could be the fuel cooler or 1/2 farad microflux... from past future.
Junk on nut with tube could be refrigerant oil or anti-corrosion junk from the factory. Clean the nut
an tube area well and ditto above.

Leon Speed

Second is the fuel cooler. Fuel is cooled before it returns to the fuel tank.

And you have a severe vacuum leak. Your HVAC system won't work too well

captcashew

So are you sure that is a severe vacuum leak or is that just a guess?

captcashew

And I assume the fuel cooler has nothing to do with the AC system so that obviously isn't a leak I need to worry about, right?

griffiths

Common failure ("vacuum leak"):
http://www.nichols.nu/tip492.htm

outbackgeorgia

Wrong, The fuel cooler has two large o rings that can leak refrigerant! I just replaced all my o rings, charged with R134a and am observing 40 f at the central vent. I do have a Kuhel compressor.
If you haven't replaced ALL 14 (I believe) o rings, you are just wasting time and $.
Dave

captcashew

Well, it's hard to say what happened with the previous owner. He did the R134a conversion and unless I am mistaken changing all the o rings is a main part of that process. But I believe he also told me the shop that did that change was a bunch of idiots. So who knows.

Back to the vacuum issue. Not to be dense, but what in those pictures leads you to think that there is also a vacuum issue. To me it could just be a leak in the expansion valve. And now, perhaps in the o rigns with the fuel cooler.

Then again, since the guys who replaced my stereo head unit also accidentally unplugged the AC switch, and from what I remember there is also some vacuum lines behind the center console, I guess they could have screwed something else like that up. I'm regretting using them more and more.

928 at last

You seem to have a lot of loose crap on the MAF. Vacuum off carefully. You don't want that sucked into the motor.

Leon Speed

Maybe I am seeing things wrong. In the picture of the fuel cooler it looks like the white vacuum line runs over the top of the fuel cooler and is cracked in several places. Or does it disappear behind the fuel cooler and is the firewall insulation folding forwards. That might create the illusion of the cracked line.

The thick A/C line that you see there covered with oil runs through the fuel cooler and cools the fuel. There are two o-rings on the A/C-line to the fuel cooler, one on each end. If you are going to change the expansion valve, the system will be empty and it is very easy to change the other o-rings. If I were you, I would carefully check all joints in the system and replace all o-rings. Especially when people say the shop who did the conversion might have been a bunch of idiots

captcashew

Ah, then that makes a lot more sense on why you think the vacuum system is in horrible shape. Sorry, that photo isn't very clear. Yeah, it does sort of look that way. I'll double check it, obviously, but I think that is actually a sticker or something peeling away from the insulation on the fuel cooler. I'm pretty sure I would have noticed the vacuum tube deteriorating the way it looks in the photo. I'll feel like a real idiot of I take things apart again and see that you saw that and I didn't.

I hate to do it, but I'd better order the other o rings and change them just to be sure. When my expansion valve and o rings arrive from griffiths today and if we get to work on it today, seeing what color the o rings that are on the old one should give an indication as well. If they aren't green, which is sounds like a recent R134a conversion should have, then it's probably safe to assume there are issues with the o rings in the whole system.

One other thing I was considering, if my mechanic put in too much refrigerant and had the pressure too high, could that have caused some of the o rings to fail? I think I saw that for 134a the pressure should be about 80% of what it was for R12. I should probably check on this.

jeff spahn

Don't forget the Nylog when you change the o rings unless you want to go back and do it again later.

captcashew

OK, I'll make sure they remember the nylog. My mechanic is pretty good, but it won't hurt to remind him. I'm sure he appreciates it.

I was just reviewing the Pirtle AC Service instructions and noticed something. When we were taking off the air filter and box, we actually found the light blue cap that is shown in the low-side port photo (near item #2 here http://members.rennlist.com/pirtle/svc_ac.html ), so it's obvious someone has been in there. Not a good sign to see that not where it is supposed to be though. Could not having that cap in place have been causing some issues too?

SteveG

Unless there is some kit put together by our suppliers with another component like a dryer, you don't need to order "o"-rings. They are not specific to the shark. Usually they come as an assortment of sizes available at most auto stores. The blue or red cap wouldn't hold pressure on a leaking valve, it's just there to keep debris out, but that is important b/c sand/gunk likes to get into those kind of nooks. You can find threaded brass replacements, which I like better than plastic, but the plastic is fine if it stays in place.

captcashew

OK, here is the latest. We replaced the expansion valve and the o-rings which seemed to have been leaking bad. Recharged the system. Turned it on. But not much cool in the car. It's hot and humid today with the temp around 90 degrees and we were only getting about 80 degrees out of the vents. We are getting about 60 degrees out of the expansion valve, so it seems that there is some issue getting the cool air into the cabin. Any thoughts? I was still going to do the heater control valve replacement once I get the part, but it hasn't arrived yet.

One other things of note, when we tried turning on teh defrost, it didn't blow cold air as well until we manually shut all the vents on the dash. This is making me thing it might be a vacuum system issue to? Maybe? If so, where can I find a diagram of the vacuum system. I probably have it somewhere, just need to dig it up.

Seems like this one never ends.

Jeff, I see you are in the Iowa area in Dubuque. I'm in Iowa City. Who do you use as your 928 mechanic or do you do it all yourself? I just feel like if I could find someone good, they could figure it out with no trouble.

SQLGuy

There's a good chance you also have leaking vacuum actuators. Vacuum actuators are used to switch flaps like the footwell flap for recirculation. These get small tears in them, leak vacuum, and then nothing in the HVAC system works correctly. One effect of this is that, for instance, your heater cutoff valve may not close, because it can't get enough vacuum.

The vacuum actuators are controlled by color-coded lines running from a manifold that sits on the torque tube hump in front of the center console. It's a bit of a pain to get to because of the middle screw of three that holds it in place. To be really sure about the various actuators, you should pull that manifold out, then test each of the lines with a Mity-vac (available at tool shops or auto parts stores for about $45 or so).

Without disassembling things, though, you can still verify the behavior of parts of the system: when it's hot, the engine's running, and the A/C is on, the comb flap inside the center vent should lift up, and the heater control valve arm should pull full closed. When you set to recirc, the passenger footwell flap should open. If you're not seeing these behaviors, repairs will likely be needed. I had torn comb flap actuators in both my '88 and '93. The '93 also came with a torn HCV actuator.