Auto Service World
Feature   July 1, 2003   by Rick Cogbill a.k.a. Slim Shambles

The Never-Ending Journey

I had just returned from vacation and I needed a rest. Thankfully it was Monday, so I could bury myself back into the relaxing world of automotive troubles. Anything was better than what I had been th...

I had just returned from vacation and I needed a rest. Thankfully it was Monday, so I could bury myself back into the relaxing world of automotive troubles. Anything was better than what I had been through in the past two weeks.

“Hey Boss,” said Beanie, “how was the trip to Yellowstone?”

I winced. “Long and excruciating. If it’s true that a journey of 1000 miles begins with a single step, then I got off on the wrong foot.”

Basil looked up from his deck of cards. “A few rough spots along the way?”

“Hah!” I snorted. “I swear someone was out to get us. Two flat tires on the first day, road construction around just about every other corner, the charging system broke down in my truck three times, and to top it off, the air conditioning in my 5th wheel packed it in. Ever try to sleep three kids, a wife and a dog in a cramped RV when it’s over 35 Celsius in the shade?”

Basil whistled. “That sounds like a disappointing trip.”

“That ain’t the worst of it,” I continued. “By the time we got to Yellowstone National Park, even I was feeling car sick. Every time Old Faithful erupted I had to run for the washroom.”

Beanie shuddered. “You need to get your mind on something else, like maybe this air conditioning problem that Basil’s been letting me play with.”

My ears perked up. “A/C? Bring it on. I could use a nice easy job.”

Beanie wasn’t so sure. “Maybe you’d better take a look first…”

What he’d been working on was a 1992 Lincoln Continental with a 3.8 litre engine and automatic climate control. The A/C hadn’t worked since the owner had bought the car, and now he wanted to fix it up.

“At first I thought there was an electrical control problem,” explained Beanie, “because the compressor clutch wouldn’t engage. Then Basil tapped on the clutch with a hammer and away it went.”

I took a quick peek. “Okay, so the air gap is a little wide. What else?”

Beanie took off his cap and scratched his head. “Well, even with the compressor engaged, it won’t cool. There’s over 90lbs pressure in the system, so it’s not like it’s empty.” He pointed to the pressure gauges. “The gauges won’t move. Basically nothing happens when the compressor turns. Here, I’ll show you.” Beanie started the car and turned the system to Max Cooling. He tapped on the compressor clutch, but now it wouldn’t even engage. I checked both the wiring connectors at the clutch and the low-pressure switch for voltage.

“You’ve got no power here, Bean,” I said.

He shook his head. “See what I mean? The last time I tested, there was 12 volts.”

Thus began a long and tedious repair that left me wondering what I had gotten myself into. The ‘on again, off again’ voltage to the compressor turned out to be a problem in the climate control module in the dash. I pulled the module out to do some pin testing and found that by twisting or squeezing the module, the power for the compressor would come and go. No used modules were available and new ones were very expensive. So I pulled out the circuit board, located and resoldered some loose connections, and now I had constant power to the compressor clutch.

The compressor was obviously hooped, since it wouldn’t produce, so we ordered a new one, along with a retrofit kit to change over to R-134A refrigerant. Just to be sure I replaced the receiver/drier and the low-pressure hose that came with it.

It was a very hot day, and I had a hard time getting the new refrigerant into the system, but finally it was blowing cool air and we sent the customer on his way. But two days later he was back with excessive high-side pressure, and the low side sucking down way too quickly. The compressor was also cycling rapidly.

“There must be a restriction,” said Basil, as he watched the gauges. “Where’s the orifice tube and filter on this model?”

I pointed to the liquid line between the condenser and the firewall. “Right in the middle of that hose,” I said. “You can’t remove it without cutting things open, so you basically have to replace the entire hose.” That we did, and the system worked like a charm. When we cut the old hose apart and removed the orifice tube, we could see it was plugged with debris from the old compressor.

“So let me get this right,” said Beanie later in the coffee room. “We had an intermittent power supply problem from the dash control unit; the air gap on the compressor was too wide; the compressor itself wouldn’t pump anything; and the orifice tube would plug from time to time.” He stopped counting on his fingers and looked up. “That’s quite a trip down the ol’ A/C highway. I think we replaced just about everything in the system!”

I didn’t say anything. Sometimes you never know where you’re going to end up when you start down the road. Just then Friendly Glen pulled up in a ’91 Ford Ranger from his used car lot. “Hey, Slim,” he said when I came out. “The A/C won’t work. Could you take a quick look for me?”

I opened the hood, and there was the same type of compressor that had been on the ’92 Lincoln, with an air gap just as wide. “Let me guess,” I said. “If you tap on the clutch, it’ll engage but it still won’t cool?”

Glen stared at me. “How did you guess that?”

I sighed. “Been there, done that.” I pulled out my pen and estimate pad, and started writing down numbers. “Here, allow me to draw you a map…”

About The Writer

Rick Cogbill is a freelance writer living in the Okanagan valley of Southern British Columbia. A licensed technician with over 25 years in the automotive repair industry, including ten years as a shop owner, Cogbill creates his comic scenarios with Slim, Basil, Tooner, and The Bean out of actual case histories. “What you have just read is true,” drawls Slim Shambles. “Only the names have been changed to protect my hide!”

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