Hi,

I have a 04 Grand Marquis and had to refill the A/C 2 years ago. This was done by a company here in town, and it blew ice cold air for a week. Then the ice cold was gone, and it was back to the half cold I had been used to for a while. It was like that for the entire winter after, and last summer (2017) but during the winter 2017/2018 the half cold started to go downhill, and it took longer and longer time for it to kick in. I mean until the little cold it could manage came. So, I scratched my head since I am from Norway originally and not used to A/C. But, finally I got some courage and bought a can with 134a at Walmart, and topped it up. It blew much colder, and this problem that I have to drive around for like 15 minutes before it kicks in, that continued. Now I still have to drive for 15 minutes, and when it finally kicks in, it blows rather cold, but not ice cold. Then, it I stop and go into a store and if I am quick to get out again, the cold comes on again more or less right away. But, if I am in the store for a long time, then I have to drive for maybe 5 minutes, or even a bit more until it kicks in again. I have checked this, and it is the A/C compressor clutch that does not engage before it has been running for this quite long time. I have just bought a little vacuum pump, and gauges and hoses, so I can at least do some jobs on it. My problem is that I am not 100% sure what I am doing.
I am a mechanic and electrician by trade, but not an auto mechanic. Even if I have had cars and farm tractors as a hobby all my life, and repaired and overhauled engines, transmissions, brakes, rear ends, and steering stuff on many cars. Just that A/C is a strange dick for me since I come from the chilly Lala land.

Bill

 

Your A/C clutch will not kick in until the ENGINE achieves it's operating temperature.
That may take a bit longer in Norway.

 

Hi, and thank you for getting back to me.

I am sorry, I live in California (but originally from Norway), and it is the same issue if it is 90-100 outside, and it did not use to be like this. But, I will take it for a drive and see how long it takes for the engine to reach normal temperature, I mean, it could be a faulty thermostat that is fully open all the time.

Bill

 

Hello, Bill, and welcome to the Grand Marquis forum.
I'm Chuck, living in Phoenix, AZ.
The needle on the temperature gauge should be at 3 o'clock when engine is at operating temp.
If your ambient air temps are 90-100, your engine should be at operating temp at 2-3 miles of driving.
As for the thermostat -- When in doubt, throw it OUT !!
The correct thermostat for your engine is: Motorcraft RT 1234.
You will need a new gasket: Motorcraft RG 571
Thermo and gasket are available at Amazon.com
Remove thermostat housing bolts - remove old thermostat and gasket.
Clean bolts and housing thoroughly -- apply WD-40 to the bolt threads.
Install new thermostat with springs pointing DOWN.
Gasket goes on TOP of thermostat.
Tighten bolts EVENLY to 18 ft/lbs.

 

Hi, and thank you for getting back to me.

I am sorry, I live in California (but originally from Norway), and it is the same issue if it is 90-100 outside, and it did not use to be like this. But, I will take it for a drive and see how long it takes for the engine to reach normal temperature, I mean, it could be a faulty thermostat that is fully open all the time.

Bill

 

Hi, and thank you for the welcome.

Took it for a drive, drove for 25 minutes, engine did not reach temperature until I stopped for some roadwork after going in 65 at the freeway. Then the AC kicked in. Got a new thermostat and seal, and have replaced it. Engine gets warm fast, after 1-2 miles in 90+F, and stays steady warm.

AC still stupid. Was just out now, and it took for ever to get it to come on. I assume it is a relay for the AC compressor clutch. Could that be half faulty ?

I also have a brand new AC vacuum pump, red, blue and yellow hoses, and blue and red gauges and the valve block. Never used it before though, got it a few days ago.

As I said in my initial post, I am not used to AC systems, and my background you can see in my initial post too. So, I am used to work on cars. And I belong to those who stop before I damage things, I rather ask than do something stupid and make a fool of myself. Because someone will discover it anyway.


Bill

 

Yo, Bill --
Yes, the A/C compressor clutch relay could be faulty. If you can find it, replace it.
Question:
Can you see the compressor clutch face when the engine is running ??
The face plate should be spinning when the A/C kicks in.

To visibly check your compressor clutch function:
Bring engine to operating temp.
Lift the hood.
Open all car doors and windows.
Open all dash vents.
Turn temp to it's lowest setting.
Turn A/C ON.- MAX COOL
Check under hood to see if clutch face is spinning.
Clutch face should alternate from stopped to spinning as the A/C cycles on and off.
If clutch face spins momentarily and stops in a few seconds, it indicates that a "charge" is needed.
You said you have the gauge set. If you're experienced with it's use, and you know how to compensate for ambient temps, you might buy the 134a and charge it that way.

Personally, I would opt for this product, as there is no ambient temperature compensation involved.:
ACP-100CA - "A/C PRO" -- This is the CALIFORNIA -Approved do-it-yourself A/C charging kit.
It includes:
20 OZ. - 134a refrigerant.
1 - Low-Side Coupler.
1 - Re-Usable, Detachable, Charge-Indicator Gauge, with Trigger
1 - High-pressure, braided steel hose.
1 - Instruction leaflet.
There's nothing to assemble -- it comes ready-to-go.
I bought one at a parts shop in Dana Point, CA. -- Too expensive!
Check Amazon.com or Wal-Mart for a decent price.
Lemme know how you make out :>)

 

It took me a while. Anyway, the A/C is working normally now, except for the tiny tiny little leak I can not find. But, at least it works normal, and come on right away when I start the engine and start driving.

I suspected the relay, since relays are well, they are are what they are, moody maybe we can call them when they get a little older.

Anyway, finally I found out what relay it was, it is number 204 on a 2004 Mercury Grand Marquis, and located in the box to the rear of the battery (right side of engine compartment). It was hard to get out, like it was stuck. Easy to get to, just stuck. So, some wiggling back and forth and then I took the cover of it. But, the relay contacts are hidden under some plastic, so it is impossible to see if they are fine or not. Except, when turning the relay in different positions small pieces of carbon fell out of it. I took some fine abrasive cloth and cut a narrow strip of it with a bend on, and put it in where I assumed the contacts where, pressed the top contact down to get the abrasive cloth stuck in between, and pulled it out. Many times, and then turned the abrasive cloth upside down to clean the other contact. So, after a while I thought it was enough, and used compressed air to get loose stuff out, put the cover back on, sprayed with WD 40 in the box where it was sitting and put the relay back in the car, started, and took it out for a drive. The A/C never came on after this, and I figured that I must have filled the crater with carbon and whatever, and that the compressed air did not get it cleaned up. Bought a new relay at the Ford dealer, put the new relay in there and then, went in to start, and the A/C came right on. And it has been like that ever since.

The relay is much easier to get in and out after I sprayed the WD 40 there. This must not be taken as an advertising for WD 40, I assume anything lubricant wise would make it easier to get in and out.


Thank you everybody for all help.