The 'Burb

[SAATR]

So, got several things done this weekend. First on the list was the torque converter. My little brother and I dropped the trans out and pulled the converter. Input shaft looked good, no issues or damage to speak of. Flexplate was fine with no warpage or cracking visible, so it stayed. Rear main seal was dry as Melba Toast, so I left that alone as well. Looks like my oil leaks are likely the oil cooler adapter and the pan, which I will address.... some day. Will likely pull the engine out and reseal one day, maybe roll in new bearings for ***** and giggles. Filled the converter with some synthetic ATF that I get from work, and installed. I realized after I pulled the old converter that I had, in my haste, completely forgotten to get a new input shaft o-ring. This resulted in a heart felt cussing fit that put me in a damned foul mood. Coffee and cigarettes were consumed. More cussing. Eventually I got over it and, with time pressing, popped the new converter on the trans. After bolting her back up and dealing with the cooler line clips (copious cussing) and myriad brackets and clips that go on the studs of the bellhousing bolts (sailors were blushing, somewhere) I set her down and filled the trans. Ran through the gears, topped off the fluid. Ran gears again, topped off fluid. Rinse and repeat. Finally got the hot fluid level in spec and.... and... still some lockup slippage under moderate throttle. Somewhere, beyond this world perhaps, the guy that designed the 4L60/700R4 sat up with a start as his ears burst into flames. I was hot. I was DAMNED hot. My fault for failing to order everything I needed, absolutely. But... it felt good at the moment. Once my blood pressure came back to cruising altitude, I dragged my ass back home and had a beer to salve my wounds. If I have to pull the damned trans out to replace one cheesy ass o-ring, so be it. Life will go on.

There was a positive note this weekend. After installing the converter I decided to finish off the AC install/service and clean the evap core. Using a calibrated thermometer I had been getting outlet temps of around 42F with an upper 60's to 70F ambient. Decent, but not good enough. Compressor was hitting low pressure cutoff and I had the feeling that my evaporator efficiency wasn't what it should be. This was confirmed by infrared thermo readings at the inlet and outlet of the evap. In an ideal system, you should have the same temperature reading at the inlet and outlet of the evaporator. Heat transfer is performed by the low pressure liquid refrigerant expanding into a low pressure gas in the evaporator with no change in temperature of the refrigerant. In practice, due to operating conditions and their effect on orifice/heat exchanger efficiencies, this isn't the case. You will usually see some rise in temps from one side to the other. If you see a DROP from the inlet to the outlet, then you generally have a flow restriction in the evap core OR poor evaporator efficiency. Poor heat exchange can result in liquid refrigerant coming out of the evaporator into the drier, which is why you can see lower temps on the outlet and have poor cooling performance.

Given all of that, I expecting some crud, but not what I found. I popped the glove box off and removed the blower motor. Reached my hand in and pulled this out:

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Oi. That's a lot of crap for such a tiny heat exchanger. I decided to get a better look at things and poked by cell camera in the hole and found this mess:

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ERMAGHERD! Luckily I came prepared for this eventuality:

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Sprayed the evap down with this stuff and then hosed it out. And again. And again. Till we got this:

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Got rid of a lot of dirt, but still had some caked on crap at the top and left. What kind of caked on crap? Hair. Dog hair, to be specific. And I've only hauled a dog once or twice in my time with das 'Burb. So some OLD dog hair. Whooped out an old tooth brush and scrubbed that **** off. And then sprayed and hosed again. And again... and again. Finally, after getting sliced up nicely by the evap fins, I reached this point:

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And with that, I said, It IS Done. I put the blower back in and reassembled the rest. Results were better airflow, less fan noise, and better smelling air. Also managed to hit around 38F with the same ambient as before. So better evap efficiency too. I'll get some better weather for testing in the near future, but I think the AC is about as good as it will get. Will be installing the condenser fan to see if I can keep the idle AC temps down.

And that's the way it was...

 

[slowburb]

Man the play by play commentary you kick is like nothing I've seen before. Your HVAC analysis is over my head, not even going to act like I know what you're talking about there. What did I get out of it? AC isn't cold? Clean that ****.

The converter...although you noticed some slippage, did it launch better? Less recovery time to get back in the sweet spot?

 

[SAATR]

I try to make it entertaining. At least that's the hope!

You got the gist of it, definitely. 20 years is a long time for **** to accumulate in the evap core. No matter how well your AC works, if you haven't cleaned that out, it could work better. I figured it was going to be nasty, but that took the cake.

The converter I pulled out was a 2400 to 2600 stall from RevMax. The S10 converter is very similar, but is a bit tighter at part throttle, which is nice. I never knew how much a difference a converter could make till I threw that thing in there. The old converter made a ticking noise at idle, which leads me to believe that something failed or was failing internally. No more noise with the new converter. It didn't slip during my interstate run today, so maybe the slipping I got last night was just some air still trapped in there or some other anomaly. Hopefully. Maybe. But yes, gets in the sweet spot and then s comes right back between shifts. Definitely a worthwhile investment.

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[SAATR]

I need to find that guy Murphy and kick him in the balls. AC has been working perfectly for a few weeks and the damned front heater core takes a ****. Fortunately it isn't too hard to get to on these trucks. Vise grips on the heater hoses for now. Have to make do with a jacket on the chilly mornings till I have time to fix it this weekend. Probably will pull the converter back out, replace the o-ring, and properly shim the flexplate so that the input shafts are seated properly in the converter.

Oh, yeah, and the Bank 2 catalyst decided to come apart and start rattling like a tin can full of rocks. Probably will go ahead and get the 3/4 ton exhaust from the scrap yard and install it. Maybe. Hopefully. If I have time.

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[99'Subourbon]

So how bad of a job is it to completely redo the A/C like you did - getting ready to do it myself. Are you supposed to flush the system after or before the install of all the new parts? Seems like flushing it after would mean you are putting all the crap into your fresh parts.

Thanks,

 

[SAATR]

So how bad of a job is it to completely redo the A/C like you did - getting ready to do it myself. Are you supposed to flush the system after or before the install of all the new parts? Seems like flushing it after would mean you are putting all the crap into your fresh parts.

Thanks,

It's an undertaking, that much is certain. I've done AC on automobiles and heavy equipment professionally for years, so it's fairly routine. Compressor, condenser, and the drier aren't too bad, except for the lines. You'll need a good set of wrenches, some penetrating oil, and a heat gun or propane torch. The condenser lines tend to be very corroded given their operating temp, exposure to rain, and the fact that the lines are aluminum and the nuts are steel. A new condenser is a given, but be prepared to buy new lines if you mangle them getting them off. This is unavoidable sometimes. If you have debris in the system from a compressor failure, you'll have to pull the rear unit and change out the expansion valve, no question. If the compressor didn't fail internally, you can look at the orifice tube to tell if you need to go to the trouble of pulling the rear unit to get to the expansion valve. If it only has a spec or two of metal in it, then you are fine. If it looks like silver paint, then you're pulling the rear unit if you want the back system working properly.

The orifice tube and expansion valve cannot be flushed. Nor can the drier, because of the desiccant it contains. The condenser cannot be properly flushed. It's where most debris accumulates, and should be replaced regardless. You will want to disconnect all the lines and remove the condenser, drier, and orifice tube before you flush. You'll want access to a good compressor with a good filter and preferably a desiccant style drier on it. I bought a pressure regulator/filter and disposable desiccant drier from Harbor Freight for less than $30. Absolutely necessary so that you don't get oil and water in the lines when you are blowing the flush out. After you flush, you have to blow clean air through the line until there is absolutely no flush coming out. Some say that you can't flush the manifold lines because of the mufflers (cylinders built into the lines) are baffled and you can't get all the flush out. I had no problems, just had to run air through them from both ends until nothing came out. The evaporator ( or evaporators, if you have to pull the back unit) takes the longest to flush because it has so many passages for flush to hide in. You'll probably spend 30 minutes or more trying to blow it all out.

Like I said in my prior posts, get a parallel flow condenser if you want the best performance. I thought I was getting one, but it turned out to be the OE style serpentine flow. I believe RockAuto sells one under the Spectra or GMB brands. The Denso (which is really a Sanden) compressor is great. I would definitely recommend it above the factory style HT6. If you use it, you'll want to use Sanden SP-15 oil or PAG100.

There's a lot more info I can give you, just depending on what you want to know. I've been doing AC for a long time, and am a bit more... meticulous than some others might be. It pays off. If you have any questions or problems, PM me. If you prefer the phone, I'll give you my number. I'm happy to help.

 

[SAATR]

As a mechanic, problems that I can't isolate and correct piss me off. Severely. It's part of the mentality that goes with wanting to fix... well, everything. Same goes for resolutions that don't have a cause tied to them. Such is the case with the lockup clutch in my torque converter. Last weekend, out of the blue, it starts locking up SOLID. It is exactly what I thought the PMW delete valve from Transgo should do when I installed it. Rolling along round 40 or 45, and BOOM, like you dumped the clutch in a semi. Why did it start working? I have my theories. Most center on the spool valve in the pump that diverts oil to the clutch when the TCC solenoid engages. I honestly think there may have been a piece of trash in it that kept it from fully closing, preventing full apply pressure from reaching the clutch. The other theory revolves around infinite improbability drives and the number 42. Either way, it works, and I am thankful.

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