Chevy Impala SS Forum banner

1 - 20 of 26 Posts

·
Registered
Joined
·
237 Posts
Discussion Starter · #1 ·
About two weeks ago I noticed that the air conditioning in my 95 9C1 was not cooling, and I also noticed the air in the car seemed much more humid. The air is blowing cool, but not cold.

I had replaced the primary cooling fan at the beginning of the summer, and at that time I saw both fans spinning with the AC on.

I checked the maxi-fuse and the relay for the secondary fan, so right now I'm assuming the secondary fan failed with an open condition, so no spinning and no blowing of the fuse.

QUESTIONS:
How much of an effect would the second fan being out have on cooling and dehumidification in city driving? The air does seem cool, but not cold. Is it wishful thinking to think the main problem with the AC is this fan being out, or is it likely also a leak or bad compressor? I'm not an AC guy, so I don't have experience with how much of an effect the fans have on performance. I know they are a factor, but how big a factor?

Am I right that when the AC is on, both fans automatically come on? I hate to ask this as I am almost sure, but I wanted to confirm it.

THANK YOU,

Lee
 

·
Registered
Joined
·
3,505 Posts
You must read previous posts and do "seaches" on this site. No, the primary fan is the one on the passenger side. It comes on when the A/C is on or if the A/C is off and the temp gets to 228 degrees. The other one is the secondary fan and it comes on when the temp gets to 232 degrees.
If both fans are on, something is wrong and you need to find out what is going on. Get it scanned for codes, checked for major overheating, etc.
Do some research here regarding testing fans and relays. Yes these things will affect the operation of the A/C.
 

·
Registered
Joined
·
237 Posts
Discussion Starter · #3 ·
1) Yes, the primary fan, on the passenger side, is the one I replaced at the beginning of the summer.

2) I agree with the temperature related behaviors that you quoted. However, my understanding is that in addition to those behaviors, it is normal and correct for both the primary and secondary cooling fans to come on and stay on when the AC is turned on. I'm looking for a confirmation on that.

3) I tried some searches and could not find what I was looking for. Please feel free to suggest some search terms, or provide some links to the information that you think would be helpful.

Thanks so much.

Lee
 

·
Registered
Joined
·
3,505 Posts
"it is normal and correct for both the primary and secondary cooling fans to come on and stay on when the AC is turned on. I'm looking for a confirmation on that."

It is not correct, believe it or don't.
 

·
Registered
Joined
·
237 Posts
Discussion Starter · #5 ·
A friend looked it up for me.

From the 1995 Service Manual, Carline B, for Caprice, Impala SS, and Roadmaster, book 3 "Service Manual Update" GMP/95-B-UPD:

Page 6E3-C12-4:

"3. The cooling fans (plural) should come "ON" anytime A/C system is operating. Engine coolant temperature must be below 212 degrees F when performing this step."

Now if I knew what effect the secondary cooling fan would have on city driving A/C, I would be all set!

Lee
 

·
Registered
Joined
·
3,096 Posts
As previously stated in this thread and in MANY posts on this forum, the primary fan always runs when the AC is on. The secondary runs only when required (hot enough). Now, the service manual is also correct but could have been worded better. The fact that both fans will operate with AC on, does not mean that they both run all the time.........they don't. (Yes, I read the FSM - thanks for the page reference). You need to have your AC system checked (high and low pressure), and for leaks. It is normal to require a recharge of refrigerant.
 

·
Registered
Joined
·
10,956 Posts
The second fan WILL TURN ON and run all the time with the primary fan if you live in a horribly hot place like FLA. High AC pressures from high heat will keep both electric fans running.. It used to happen to me on the maybe 5 hot summer days up in the north country.

Just test the fan. Disconnect the connector. Run a fused lead from the battery to the fan and a ground - ground. If it spins its fine.
 

·
Registered
Joined
·
237 Posts
Discussion Starter · #8 · (Edited)
Thank you. I will check the secondary fan as you suggested. And ultimately I will get all those other AC things checked also. Just trying to start with the simple stuff first.

Also, it was hot, but not insanely hot when I saw both fans running with the AC on at the beginning of the summer.

L.
 

·
Registered
Joined
·
2,093 Posts
The following is a quote from www.theherd.com/articles/lt1_cool.html
The B/D-car coolant fans operate under PCM control at the following engine temperatures and A/C system pressures:

Fan ................. Mode ... Temp ................ A/C Pressure
Primary ... (RH) Fan ON: 109°C/229°F, OR 189 psi
Primary ... (RH) Fan OFF: 105°C/221°F, OR 150 psi
Secondary (LH) Fan ON: 112°C/234°F, OR 240 psi
Secondary (LH) Fan OFF: 108°C/227°F, OR 210 psi


Additionally, the PCM will turn off the fans at higher vehicle speeds (above 48 MPH I believe) since running fans can actually impede airflow through the radiator at high speed. Each fan also has a minimum running time. Once activated, the primary fan will run for a minimum of 50 seconds, and the secondary fan for a minimum of 26 seconds. Finally, certain Diagnostic Trouble Codes (DTCs) may cause the PCM to turn on one or both fans.
The 2ndary fan may come on from time to time, but the primary fan will do most of the work most of the time - unless it's really hot, either out there, or under the hood.

As the figures above show, GM's settings allow the car to come close to - though not quite - overheating.

Some aftermarket PCM tunes lower the temp thresholds so that both fans are nearly constantly on, depending on either the weather, the thermostat being used, or both.
 

·
Registered
Joined
·
5,693 Posts
I have never seen/heard my secorday fan come on after I replaced the primary. It works, but as stated before, the sec. fan is a back-up/last resort thing...if everything else is working correctly you shouldn't see the sec. fan run at all, A/C or not, really hot or not....unless you live in Death Valley or a couple of cities around here , you don't get THAT hot...FLa....let's see, how many day's of 110 degree 's did you see this summer?

IIRC the fans are also shut off at speed....I think 45mph or higher as they tend to restrict airflow if running above that speed.
 

·
Registered
Joined
·
237 Posts
Discussion Starter · #12 ·
Update

Hello All:

I hadn't done anything about this yet, but of course since it's spring now I'm on the case again as things get warmer.

I really wanted to thank everyone who posted on this thread, the information you all gave me is going to save me a TON of time.

My friend hooked me up with his friend who is one of the top mechanics at a local dealership here is PA. The only problem is it is a FORD dealer. LOL!

He was able to inspect the car today and put stickers on it. He also found out that the noise I've been hearing for months is coming from the AC compressor. My last Caprice needed a compressor when I got it, same kind of thing I think, the clutch/pulley was all messed up and rubbing on itself.

He also found that their was no cotter pin on the left side lower ball joint, and the nut was about to come off it.

Everything except the ball joint looks like typical and manageable issues. I'm furious because the shop that inpected the car last year hit me for a ton of brake work, all four shocks, and upper and lower ball joints. My friend's mechanic pointed out to me that the car was dealer serviced constantly before I brought it, and he finds it extremely suspect that all that stuff suddenly went bad in a 6000 mile period! The same shop that did all that didn't put a cotter pin on the left lower ball joint, and didn't torque the nuts on both front wheels. When I got the car back last year the left front wheel almost fell off from that.

I've been going through a lot, unemployed since April of last year. When the car was inspected last March right before my job ended, I was in no mindset to deal with the issues, and I trusted the mechanic when he said I needed $2100 worth of work.

I clearly need to re-evaluate some of my decisions in the future...

Lee

PS - I also need to figure out if it's EVER a good idea to try to repair a compressor or get a rebuilt one. I've always been told not to cheap out and buy a brand new one from GM, but money is so tight.
 

·
Registered
Joined
·
3,096 Posts
Hello All:

PS - I also need to figure out if it's EVER a good idea to try to repair a compressor or get a rebuilt one. I've always been told not to cheap out and buy a brand new one from GM, but money is so tight.

It is wise to buy a new GM compressor but don't buy it from GM.......$$$

Check Amazon and ebay - be sure it is correct for your car and includes the clutch. Spend another $30 for new accumulator and orifice filter.
 

·
Registered
Joined
·
237 Posts
Discussion Starter · #14 ·
Thanks Grandpa!

I will be looking into that very soon.

Any thoughts what a new GM compressor goes for these days?

Lee
 

·
Registered
Joined
·
3,096 Posts

·
Registered
Joined
·
237 Posts
Discussion Starter · #16 ·
Wow.

Thanks Grandpa!

I appreciate the help!

I had no idea the compressors could be under $300.

From what I remember, when I had my 91 Trans-Am converted from R-12 to 134a, it needed a new compressor and dryer bottle and some other parts, plus a complete evacuation of course. This was at least 7 or 8 years ago, and I think they hit me with a bill for like $1200. I think they said the conversion compressor was more expensive than for a car that was 134a from the factory, but I'm not certain about that.

I have an appointment on Thursday for an estimate, so we'll see what they try to hit me with.

Today as per a post by cletus284, I unplugged the connector at the waterpump and was somewhat surprised to see that both fans came on! I replaced both fans and both relays, so seeing that they are both working, apparently whatever I was trying to do before to get the secondary fan to spin was not correct.

So if I can get the compressor fixed I should be in a lot better shape.

Again, my thanks.
 

·
Registered
Joined
·
3,096 Posts
I bought a new GM compressor, accumulator (receiver/dryer), orifice tube and took them to a good AC shop.

They charged me $250 for the complete change out which includes evacuation, new R134a, O rings, labor, etc. So my total was under $550. Their experience and expertise is worth it. AC work is one of the few things I don't do myself.

Important: That price also included labor to install 4 new plugs on the passenger side. It is so much easier while they are in there with the compressor off and hoses movable. Even if you don't think you need plugs, do it anyways. The drivers side is easy for you to do.
 

·
Registered
Joined
·
237 Posts
Discussion Starter · #18 ·
Very helpful to know.

Thanks so much, that will help a lot to decide whether to give them the job.

The good is I know they do VERY good work.

The bad is like so many shops in PA-NJ and NY what I call the Northeast corridor, prices are unbelieveably high.

I agree AC is like automatic transmissions, it's best to leave it to people who do it all the time.

This place told me on the phone they charge $75 to diagnose, no matter how little or how much time it takes. That $75 is put towards the final bill if you let them do the repair. He complained that too many people let them do the diagnosis and then go to a junkyard to get parts!

I'm annoyed because I KNOW they will do the job right but I think he will say $800-1200 with all parts and labor. You would be surprised how hard it seems around here to find someone to work on your car that is not a butcher...

Lee
 

·
Registered
Joined
·
3,096 Posts
Put your location in your signature. Someone nearby may recommend a good shop at a good price. This is not rocket science - many good independent shops out there.
 
1 - 20 of 26 Posts
Top