AC Compressor replacement

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joespanova

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I've used the search function but after surfing a little I dont find what I'm after..........I'm sure its been asked , but I dont see it.

OK , wifes 2000 LS . I keep cars for a long time so here goes. Took the car to a Lincoln dealership last year because the AC wouldn't hold a charge........was told it was leaking at the compressor manifold. I'm looking at just replacing the compressor and then moving on to the DCCV valve as it has no heat either....yes there are 2 seperate issues here.

Question is.....how much is involved in changing the compressor as far as getting to it...........it appears there is a lot to remove before I can get to it........or is it more accessable from under the car? I intend to change compressor and possibly, seals at condenser.

Any info would be appreciated.

Thanks
 
You get to it from under the car. You just have to remove the shield, disconnect the refrigerant lines, take the belt off, and remove the compressor.

Now, you said that "was told it was leaking at the compressor manifold." The compressor manifold is not the compressor, or even part of it. It's the lines that attach to the compressor. Which is it that you need to change? The compressor or the compressor manifold and tube assembly? (or both?) If it's the manifold and tube assembly, make sure that it isn't just the valve core for the suction port (this seems to be the most common problem with the compressor manifold).
 
joegr said:
You get to it from under the car. You just have to remove the shield, disconnect the refrigerant lines, take the belt off, and remove the compressor.

Now, you said that "was told it was leaking at the compressor manifold." The compressor manifold is not the compressor, or even part of it. It's the lines that attach to the compressor. Which is it that you need to change? The compressor or the compressor manifold and tube assembly? (or both?) If it's the manifold and tube assembly, make sure that it isn't just the valve core for the suction port (this seems to be the most common problem with the compressor manifold).
Click to expand...

unfortunately all I was told........and that dealership is no longer there , was that it was leaking at the manifold. I assumed without looking that he was suggesting that the seals , if there are any at that junction , are leaking. If that is not the case and since I havent even attempted to dive into the car and have a look , maybe I'm drawing the wrong conclusion here. I assumed like GM compressors that can leak at carbon seals , that the compressor and manifold attachment points are what they were referring to. Please elaborate on the tube assy and replacement ( valve core etc )
 
Since the car is so old now I also figured a comp change might not be a bad idea.......
 
The compressor attaches to the manifold via two o-ring seals. They don't seem to fail much, and if that's all it were, the dealer would have been happy to replace them and then charge you for a vacuum and refill. There would certainly be no need to replace the compressor or the manifold.

These compressors do fail over time, but you are wasting your money if you replace the compressor, and the manifold tube assembly is really at fault (not uncommon).

The valve core is inside the suction port connection on the AC manifold. It's just like the valve core on a tire valve stem. Most auto parts stores carry them. (Must get the ones for R-134a AC systems, not tire valve stem cores.)

You system has been open for a while. You'll have to replace the receiver/dryer too.
 
TooManyToys said:
A leak at the manifold would indicate the O-Rings between the manifold and compressor are the problem.
Click to expand...

Well, they could have said or meant either, but a leaking compressor manifold is not uncommon, and it's often from the suction port valve.

Certainly, since there is doubt it would be worth it to replace the o-rings (less than $5), connect a vacuum pump, and see if it will hold a vacuum.* If it will, then it was the o-rings. If it won't, then keep looking.

*: Make sure it holds a vacuum using a gauge at the high pressure port and disconnect from the suction port. (If you stay connected to the suction port and the suction valve is the leak, you won't detect it.)
 
TooManyToys said:
Posting at the same time.

Joe have you seen more line failures then O-Rings? I've just surprised.
Click to expand...

I've seen more compressor leaks than either, but I also see lots of compressor manifold leaks reported.
 
Well , I'll replace the o'rings and as you suggested the reciever dryer......but why the reciver / dryer as well?
 
The R/D if the system has been exposed to atmosphere for some time. If the system still has some pressure, even 5 psi, then it should be OK.

But you would need to check the pressure first thing in the morning when it's cool and not expanded. If a system has bled all the way down you can get into the goofy situation of normal air being drawn into the piping by heating and cooling, drawing a vacuum as it cools. If it has atmosphere air and the engine bay heats up, the air will expand in the somewhat closed environment of the piping and show a pressure. During the day the pressure will slowing bleed out (if small leak), then atmosphere will pull in as it cools overnight, contaminating the drier.

Pretty rare occurrence but I was shown it first hand. Never thought about it before then.
 
joespanova said:
Well , I'll replace the o'rings and as you suggested the reciever dryer......but why the reciver / dryer as well?
Click to expand...

Open system = air drawn in
Air drawn in = moisture
Moisture + refrigerant = acid
Acid + aluminum = hole
Hole = lost refrigerant

The receiver dryer has stuff in it to absorb moisture, but it can only do so much before it is used up.

This is also why you have to pull a vacuum of at least 29.5" for an hour or so to boil all the moisture out.
 
Thanks guys.

Joe you're always a big help........thanks again.......and if I need help , well , I'll be back LOL
 
joespanova said:
Question is.....how much is involved in changing the compressor as far as getting to it...........it appears there is a lot to remove before I can get to it........or is it more accessable from under the car? I intend to change compressor and possibly, seals at condenser.
Click to expand...

It's not too bad. Just a lot of work on your back. IIRC, with the help of my daughter (it is her car after all!) it took a couple of hours. The compressor I bought had to have the pulley, field, etc. transferred over from the old compressor and that took some time. Compressors can be purchased (Rock Auto for one) complete and all you have to do is remove the old one and replace the new. DON'T forget the oil! When you have the system recharged just tell them you need the oil too. Also, do the receiver/dryer last; for Joe's reasons.
 
Do you plan to replace the expansion valve at the same time? The repair manual stated that expansion value must be replaced if you replace the compressor. But it is redicious, to replace the expansion value, it will take a whole day, at least.
 
lan_baba said:
Do you plan to replace the expansion valve at the same time? The repair manual stated that expansion value must be replaced if you replace the compressor. But it is redicious, to replace the expansion value, it will take a whole day, at least.
Click to expand...

If the compressor itself failed, then it would have spread little metal fragments through the whole system. The expansion valve would get clogged by these. (The receiver/dryer would too.) That's why it says it must be replaced. The rest of the system can probably be flushed out.

If the compressor is being replaced because it is leaking (as is the case with this thread) or the clutch failed, then you can skip replacing the expansion valve.
 
ok, thank you very much, I will then leave the expansion valve alone. :p
joegr said:
If the compressor itself failed, then it would have spread little metal fragments through the whole system. The expansion valve would get clogged by these. (The receiver/dryer would too.) That's why it says it must be replaced. The rest of the system can probably be flushed out.

If the compressor is being replaced because it is leaking (as is the case with this thread) or the clutch failed, then you can skip replacing the expansion valve.
Click to expand...
 
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