Nonna has tons of works lined up, since this is not going to be a full restoration project, we will be doing the work piece by piece rather than completely breaking her down and waiting a year.
Who has to be first? Currently we have a running engine and transmission, a running chassis, and these are not going to continue to deteriorate in short future. In addition to the rear AC that continued to leak coolant, there were leaks in the heating pipes in the cab. I had blocked the heat valve to the rear AC before this, but the coolant that had entered the cab was still trapped there. This makes rear AC the primary target.
As Nonna came down the ramp from the trailer, we noticed a lot of green fluid coming out of the front of the rear axle. It’s coolant. I found coolant coming out of a hole in the underbody where there should be a rubber grommet. It looks like someone intentionally left it open to allow the coolant to drain out. Why does coolant flow out from the rear? By the way, Nonna has the optional 582 rear independent AC, and that’s the only thing that could cause the coolant to come out of there.
We quickly checked under the carpet and sure enough it was completely filled with green liquid. Not sure if it is heat exchanger or other reasons, there is no quick diagnosis method. So when I had time to start working on Nonna, I was the first to disassemble the interior. The whole interior smells damp, the sponges under the carpet soaked in coolant must have helped. Therefore, in order to have more motivation to enter the cab to test the chassis in the future, the entire cockpit also needs to be cleaned.
With the seats, center tunnel and carpet removed, the leaking area can be seen. Only the passenger side is filled with coolant and the pipes go through there. Since I parked the car on an incline, the coolant was flowing to the rear, central locking pump area. Some clever guy used a plastic bag to protect the vacuum pump and the sponge surrounding it so that they would not soak in the coolant. I consulted the former owner about this, he kept the car after it was stopped in 2018 without knowing anything about it. He was a passionate guy, one night he messaged me late, long after we had closed the deal. “Hey, I forgot to tell you, the trunk handle doesn’t work because I disconnected the vacuum pump, there’s always a leak there.”
Good thing it’s coolant, even if it’s just the cheap green kind. You know, Nonna comes from the only tropical province in China. Even if it is not tropical, just in southern China, it is very common to replace coolant with water. In that case, the cockpit may be severely corroded, making the entire vehicle useless for maintenance. Even so, I found rust on the driver’s side and signs of water running down the sides of the center tunnel. Apparently the car experienced multiple rear AC leaks and the previous driver used coolant to protect the body.
I thought the heat exchanger was leaking, but there are no green traces of coolant underneath. After further dismantling, I was pleasantly surprised to find that the box storing the evaporator was empty, leaving only the valve connecting the pipe that was blocked. Let’s see how the reliable 140 experiences this problem. EVA records regarding the rear AC warranty show that in December 1995, after only 18 months and 14,421 kilometers of driving, the rear evaporator leaked. It seems that this problem continued to bother the user in the future and caused him to eventually abandon this option.
Then there must be a leak in the pipe. There was still some coolant in the pipes, so we applied air pressure directly from the front section to check where the coolant would come out. There are three tubes in total, one is the feed line and two return lines. When we inflate the feed line, liquid spurts out from a small upward hole. The hole looks small, like it has been poked with a needle. Is it really a man-made hole? This is only superficial. Corrosion starts from the inside, so when there is only a small hole on the outside, the area of internal corrosion will be much larger. We sanded the area and many holes appeared.
Now that the repair plan has been determined, we inspect and weld all three tubes. As for the evaporator that disappeared and the heat exchanger that still works, I would install a new one. Although as many friends have said, working on the rear AC is easier than the front, I’d hate to repeat anything. Well, even factory quality evaporators only lasted a year and a half in the first place, and we shouldn’t even breathe easy for genuine parts. I ordered copies of the BEHR and they are completely original, even with the plastic casing.
I used a Kracher extractor to suck out all the coolant. To be as thorough as possible, jack up the front axle first and let the fluid flow to the rear where it collects once. Then jack up the rear axle and let the fluid flow to the front, where it collects again. Coolant never evaporates on its own, so no opportunities can be missed. During this process I discovered the unfortunate head rest module, which was filled with coolant. Although it was preserved, the plug had burned due to a short circuit.
The three welded pipes underwent multiple independent leak tests and were first installed back into the cab. Then comes the pre-assembly of the evaporator and heat exchanger, connected to the pipes. After completing this the front and rear AC panels were installed to test for leaks. Well, the rear AC isn’t working, not just the heat valve, but even the blower isn’t responding. HHT didn’t read any code, it wanted to say that the entire AC system was perfectly healthy. I unplugged fuse #1 in the trunk, which belongs to the rear AC. Not burned out, but the contacts are full of scratches, it’s probably been pulled out dozens of times? I don’t know why, maybe just to deactivate the rear AC. I installed a new fuse and the whole system works fine.
Refrigerant leakage is no cause for concern at this time. Before removing the rear AC, I found that Nonna still had a lot of refrigerant. You must know that she has not driven again in 2018. The refrigerant is still inside after 6 years, so I don’t worry about the front evaporator. I was very excited thinking about this. How cool is the rear AC? In fact, the last time I sat in the back row of a 140 was 11 years ago, let alone playing around with AC. But that doesn’t stop me from preparing for life after 90, and my kids can use it too.
After installing the cleaned carpet, she finally looked like a classy car again.
