2004 5.4L - A/C System Questions

[amish_electrician]

A/C compressor on my 2004 5.4L started making whirring sound (increased with RPM). Ruled out the clutch as the cause, so decided to play it safe and replace the compressor.

I don't wish this repair on anyone.

Drained oil from compressor, condenser and accumulator. Looked good... some dye, but no nasty black muck or metal debris. Think I caught compressor before it self destructed. Got the new compressor oiled and installed and then replaced the condenser and accumulator. Evacuated system for 1 hour. Holds vacuum... no leaks. My questions:

1) Since compressor had not failed catastrophically, I opted to just replace the compressor, condenser and accumulator. Didn't flush the lines or mess with the expansion valves or evaporators. Any opinions on this approach... good or bad?

2) While recharging the system with R134a, while shaking one of the cans, I noticed that the line connected to the can tap had become loose. (Harbor Freight manifold gauges... yeah, I know...) It hadn't loosened that much and I didn't hear any gas escaping. I hand tightened the line again and went about my business. What are the odds that air got introduced to the system? And if so, should I worry about it? Recover, evac and recharge again (being more careful)? Or am I over-thinking this one? A/C is nice and frosty cold by the way.

Thanks for any opinions or advice!

 

[stamp11127]

What are the pressures?

 

[amish_electrician]

If I recall... Low side - 30, High Side - 150.

Edit: I've read that these pressures are spot on for a Ford TXV system. It was around 72 degrees when I got these readings.

 

[stamp11127]

According to the "charts" it is a little low on refrigerant. I use the charts as a guide then tweak as needed. If the evap isn't freezing up I'd run with it keeping the evap just above freezing.

 

[Prince_Polaris]

On the subject of the 5.4L AC, is it true that I can fix both my not-really-cold rear AC and the hissing from the rear simply by adding more coolant to the system? Cause that's one of the limited things I know how to do!

 

[stamp11127]

Nope. See the stickies in the Heating & Cooling section on how the system works. Once you understand how the process works the troubleshooting is much easier.

Coolant is used in the engine cooling system - refrigerant is used in the HVAC system. Two completely different solutions.

 

[Prince_Polaris]

Nope. See the stickies in the Heating & Cooling section on how the system works. Once you understand how the process works the troubleshooting is much easier.

Coolant is used in the engine cooling system - refrigerant is used in the HVAC system. Two completely different solutions.

Yes, because I'm gonna pour radiator coolant into my AC line... you should know that on forums, reading threads that cover broad topics are never as good as asking people about your specific situations


Edit: Yeah, those threads might be helpful to someone else but those are all general AC troubleshooting (except the diagram of where the hoses go but that doesn't help me either)

 

[stamp11127]

The only thing about asking others for help very few actually know what they are talking about and may cost you a ton of money.

Read the threads, learn some things, then post facts and ask pertinent questions.

If you consider the 609 certification study guide "general AC" then you shouldn't need to ask anything on here.

Prince_Polaris, you stated the rear isn't cooling well. Nothing about the front not cooling correctly. These have 2 evaps, orifice tube in the front and txv in the back. If the front is fine, pressures are in line then there is a problem with the rear unit. You can check the txv operation with temp checks on the inlet and outlet lines to the rear evap.

 

[Prince_Polaris]

The only thing about asking others for help very few actually know what they are talking about and may cost you a ton of money.

Read the threads, learn some things, then post facts and ask pertinent questions.

If you consider the 609 certification study guide "general AC" then you shouldn't need to ask anything on here.

Prince_Polaris, you stated the rear isn't cooling well. Nothing about the front not cooling correctly. These have 2 evaps, orifice tube in the front and txv in the back. If the front is fine, pressures are in line then there is a problem with the rear unit. You can check the txv operation with temp checks on the inlet and outlet lines to the rear evap.

Jeez, even that is too complicated.... Perhaps I'll just save up money and tell a shop to look at it

So, considering that the rear AC hisses, perhaps it has a leak- does the rear AC have a line somewhere that I can hook up a can of refridgerant and fill it, then if it stops working later on I know it's messed up? I dunno, I want to learn the mechanical bits, but I also don't wanna break everything...

 

[stamp11127]

My advice now is, RTFM.....