Noise in dash an AC question

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Sep 28, 2010 | 11:18 AM

Adam Lueb

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From: Chicopee, Ma

Noise in dash an AC question

Yesterday was a cool very rainy day here in Chicopee. I was out in the X and had the parking lights on Wipers and parking lights on, in Ma it is the law that a car with its wipers on must have the lights on and heater. Then I started hearing a noise coming from behind the dash. The best I can describe the sound is a musical cymbal being stroked with a brush. I wouldn't bring this up, but this is the second time I've heard this. The first time the weather conditions were the same except warmer. Today it is raining but humid and the temp is in the low 70's. I was out for about an hour and didn't hear this noise.

I have another question, about the HVAC. When I first got the car the AC blew cool air but not cold. I took it to the Jaguar dealer they filled it checked for leaks and pressure at the compressor on both sides all were in "factory limits." Also, If I stop the car and sit for awhile, the AC warms up, as soon as I start moving the AC cools right down.

Sep 28, 2010 | 11:22 AM

sidewalkman

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From: Langley, BC

I can't really comment on your query, I've never heard the same noise but where live, you say if you have your wipers on it is a law that you have to have your parking lights on?

On the blowing warm I think you might have to replace the freon. Having pressure does not mean your freon is up to snuff. Mine blows icy regardless of whether I'm sitting or not.

Sep 28, 2010 | 01:20 PM

Thermo

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From: Great Mills, MD

Adam, as for the noise in the dash, do some looking around and putting you ear up near the dash. I bet you will find that the noise is coming from the small vent to the right of the steering wheel. If this is the case, then you are hearing the blower fan for the temperature sensor for the A/C system. Nothing to worry about.

As for your A/C system blowing warm after sitting for a bit, to me that sounds like your radiator fans are starting to go. Odds are, you are looking at your fan control module starting to fade. You can test the fans by turning on the A/C system, putting it in manual mode, setting the fan to the highest speed and then dialing the temp as low as it will go. This will force the fans to run at full speed. You should be having a really good wind blowing from the fans if you open the hood (ie, if you stick your head over the air box, it should feel like you are sticking your head out the window doing about 30 mph). If you are getting a so-so breeze, then your controllers (most likely) are starting to go.

The reason why your A/C cools down once you start driving is that the air flow over the car is more than what the fans are pulling. So, since the radiator is now getting more air flowing through it, it can cool the A/C system better.

Sep 30, 2010 | 10:04 AM

Adam Lueb

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From: Chicopee, Ma

Thanks for the info on the noise and the fans, it is pouring cats and dogs today so I will do the fan check tomorrow.

Sep 30, 2010 | 10:13 AM

Adam Lueb

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From: Chicopee, Ma

Lights

Quote:

Originally Posted by sidewalkman

Yes it is the law that when you run your wipers your lights have to be on, parking lights are the bear minimum. Also, in 08 the state motor vehicle department banned at inspection time license plate frames, none are allowed on a car. I had a license plate transponder on my front plate, as when I had a Mercedes the window type didn't work due to the electronics in the rear view mirror . I had to go to the motor vehicle department and get a letter from them that the transponder was OK. Also, banned were aftermarket window tinting. A friend purchased a SUV in 08 had all the windows tinted and flunked inspection, He had it removed and he passed. Then in 09 they changed the tinting law to a tint no more than 20%. Also, in 09 the state now requires cars and trucks to have pollution inspections every year, before it was every other year, if your car had a even last number on the license plate you had it inspected during an even year, odd number odd number year. Big brother knows what is best for us, I guess.

Sep 30, 2010 | 06:31 PM

Adam Lueb

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From: Chicopee, Ma

Hvac

Quote:

Originally Posted by Thermo

I did the test with the fans today, I had my son Allan turn on the AC set on manual and fan all the way up. I was standing in front of the car and the fans came on right away and when he turned the AC off they stopped. The fan on the drivers side is a bit hard to see as it is lower down then the other fan, I used a flashlight to make sure they were turning and there was a good bit of turbulence from the fans. So I would say they are OK.

Oct 1, 2010 | 05:34 PM

Adam Lueb

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From: Chicopee, Ma

Dash Noise

Quote:

Originally Posted by Thermo

Adam, as for the noise in the dash, do some looking around and putting you ear up near the dash. I bet you will find that the noise is coming from the small vent to the right of the steering wheel. If this is the case, then you are hearing the blower fan for the temperature sensor for the A/C system. Nothing to worry about.

The noise in the dash has not come back, but when it does I will follow your instructions.

As for your A/C system blowing warm after sitting for a bit, to me that sounds like your radiator fans are starting to go. Odds are, you are looking at your fan control module starting to fade. You can test the fans by turning on the A/C system, putting it in manual mode, setting the fan to the highest speed and then dialing the temp as low as it will go. This will force the fans to run at full speed. You should be having a really good wind blowing from the fans if you open the hood (ie, if you stick your head over the air box, it should feel like you are sticking your head out the window doing about 30 mph). If you are getting a so-so breeze, then your controllers (most likely) are starting to go.

The reason why your A/C cools down once you start driving is that the air flow over the car is more than what the fans are pulling. So, since the radiator is now getting more air flowing through it, it can cool the A/C system better.

As I told you I did the blower test and the air from the fans was OK, I did it again today,it is in the low 60's today and the fans weren't blowing as much air as when I did the test the first time. Does the air temp have any relation to how the Jaguar system works? Also, I was talking to my mechanic and he said he has never worked on a English car that had a terrific HVAC system. His explanation was that the weather in the UK is quite different then in the states and the English aren't really that concerned with cold AC.

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Oct 1, 2010 | 05:46 PM

itspec60

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From: South Central PA

I think your mechanic should rethink his position...nuff said. Sounds to me like your condenser is full of bugs and crap. This could create your situation.

Oct 3, 2010 | 05:00 PM

Adam Lueb

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From: Chicopee, Ma

Quote:

Originally Posted by itspec60

I think your mechanic should rethink his position...nuff said. Sounds to me like your condenser is full of bugs and crap. This could create your situation.

How would the condenser get full of bugs and crap as it is a closed system? Do you mean the radiator type piece in front of the radiator? I cleaned that back in June. I did notice it has a white coating on it, don't know what it is and it won't wipe off.

Oct 3, 2010 | 09:03 PM

#10

Thermo

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From: Great Mills, MD

Adam, the white layer that you are seeing that won't wipe off is the aluminum oxidizing (aka, rusting). That is normal for the aluminum for a car that age. As long as it isn't leaking, don't worry about it.

Oct 5, 2010 | 04:29 AM

#11

itspec60

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From: South Central PA

That radiator type piece is your condenser. It can get road debris like "bugs and crap" in the fins reducing it's effectiveness.

Oct 6, 2010 | 08:22 AM

#12

Adam Lueb

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From: Chicopee, Ma

Quote:

Originally Posted by itspec60

That radiator type piece is your condenser. It can get road debris like "bugs and crap" in the fins reducing it's effectiveness.

Yes I cleaned that back in June when I got the car I sprayed it down with a hose and used a boar hair bush, very lightly to clean as much as I could. I took a look at it yesterday and it is clean. Except on the top 1/4 of the fins there is some sort of white substance on them. I used a couple of cleaners to try and get if off but no go. Perhaps some paint remover will work.

Oct 6, 2010 | 10:13 AM

#13

Thermo

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From: Great Mills, MD

Adam, that white substance is aluminum oxide. If you use a product like CLR, it should remove that for you. Most cleaners are not going to touch the stuff.