Hey guys,

I just joined right now because I recently got a 2004 Volvo S40 for my first car and I love it. I just have a few questions about it I'll be asking later, but the main one is that my AC doesn't blow cold air. I don't know what the reason might be, I'm not at all a car person, but I like to think I'm mechanically inclined and can get through instructions and service manuals pretty okay. I have tools, but they're mostly for computers, phones, and tape decks. Can anyone guide me?

Thanks.

 

First thing is what model S40 are we discussing? The 2004 1.9L turbo engine or the 2004.5 2.4L 5 cylinder engine?

With the 1.9L 4 cylinder turbo engine you need to check some things. When you turn on the A/C does the compressor clutch engage? Does the cooling fan kick into high mode?

Now the newer 2004.5 model has a slightly different configuration but the basics are the same. This model has a separate belt on the compressor. Is the belt still attached? Does the compressor clutch engage? Does the fan kick up to high speed?

Let us know more and we may be able to point you in the right direction.

 

Thanks for the reply.

I used a VIN decoder and according to that, I have a 1.9L L4 DOHC 16V
TURBO engine. That's the first one right?

 

Yes, the older model. I had a 2001 of the same lineage.

Ok, so when you select A/C does the compressor clutch kick on? Does the fan kick up to high speed?

 

How would I check for the compressor clutch? Is it audible inside the car at idle?

I know the fan does kick up to higher speed based on all other cars so that I can check for in a bit.

 

Get a helper while you get a strong light to watch the clutch face of the compressor. Have them turn on the A/C while you watch. The compressor sits low down by the pax side of the engine next to the body. Sometimes they are super quiet when turning on because the engine noise is much louder. You will definitely see it begin to turn if it engages.

 

If the fan kicks up to high speed and the clutch engages on the compressor, then I would check the receiver/drier for bubbles in the sight glass. The receiver/drier is located just below the driver's side headlight. It is a bright aluminum cylinder about the size of a Redbull can. On the top you can see a little clear window. If it's not clear just wipe the dirt off. Through this window you can see bubbles in the refrigerant (R134a) if the charge is low. The bigger the bubbles, the lower the charge. This type system really makes filling the refrigerant easy. With the A/C running you shine a bright light down onto the window. Adjust your gaze as necessary to avoid the light's reflection off the glass. If the charge is low you will see bubbles quickly moving past the window. Big bubbles = low charge. Tiny bubbles = almost full. No bubbles = STOP filling cuz it's full or it's completely empty from a leak and you are looking at one big giant bubble (empty air). No bubbles and still warm means you gots more figuring to do.

If still warm and no bubbles then it's something more serious like all your refrigerant has leaked out and you need to fix the leak. At this point you take it to a professional and have them find and fix the leak.

There is another possibility, albeit a very long shot. If the blend door motor has failed and you are getting hot air mixed with your cold air which gives you warm air. This is more rare but does happen. Change the air output to different vents and see if anything changes.

 

So I went and checked everything a while ago, except the blend door motor thing because it's not a very hot day today and that could incorrectly trick us into thinking the air might be cold. I'll try that on a hot day and see what happens. But I took videos of the compressor and receiver/dryer. In the second video, you might hear me talking, but it's not very understandable due to the engine noise. I was just saying what was currently happening, like the A/C is off and compressor isn't spinning, now it's on, it's spinning, etc.

 

You can definitely see the bubbles in the window so you need a top up of R134a. If it were me I'd buy a can of R134a at the local auto parts store then buy a refill adapter. There are also one time use cans that include stop leak and other stuff that's really not needed. Up to you which to use but Volvo has a pretty good A/C system. My 2001 rarely needed a top off and was always cold. Anyway, you hook up the refill adapter to the low side port by the pax side firewall. Leave the can facing up because you want only vapor to enter the low side. If you turn the can upside down liquid will enter the low side and might damage the compressor as liquid does not compress. It's fastest to do this on a hotter day as the vapor will be pulled in faster as the system demands more refrigerant. Then you just run the engine with the A/C on high and recirc button off and windows down. You want the system to be working at it's hardest to suck in the R134a. You can setup a strong fan in front of the car to help the condenser too. Just helps speed things along. Then you watch the receiver/drier window for the bubble to get smaller and smaller until they disappear and it's only liquid. That's it, it's now full. If it's still warm I'd start looking at the blend door.

 

Ok, so does the brand or price of R134a matter? Because I can see the super cheap Walmart brand, for less than 5 bucks at 12 ounces, but there's other brands and price points as well. I have plenty of auto parts stores near me, but I don't know which product to get. I'll go look around right now, but I'll hold off on the buy until I know more. As for the refill adapter, are there specific plugs or standards that vary between makes and models? Would work? Also, where how can I locate and access the low side port? I read in other places that there's a low side and a high side port. Does this matter or do I just focus on the low side port?

Thanks.

 

Brand does not matter. Get the cheap stuff as some auto parts stores think theirs are made of gold.

Yes, that refill adapter is one of the more fancy ones with a pressure gauge but works just fine. The low pressure port has a different shape than the high pressure port so that you cannot connect them incorrectly.

The high pressure port is mainly used for system diagnostics in conjunction with a complete manifold gauge set. For the home DIY mechanic it's overkill.

 

Ok, I just bought a 12oz can. I found a hose for the same price at a shop near me, but it's closed so I'll get it tomorrow. It doesn't have the gauge on it, but as you said, I can use that little window to check the levels safely, right?

Where can I locate the port to fill from?

 

The low pressure side port is on the pax side near the firewall. Find the larger of the two aluminum lines going to the compressor. It will have a black cap screwed on the port. Yes, watch the sight glass when filling and stop when you don't see any more bubbles.

Basically, just watch a few things. When preparing your can of R134a you make sure the needle is not sticking out of the refill adapter part that screws on the can. You don't want to pierce the can until everything is ready. Then once everything is hooked up you start the A/C and hook up the adapter and open the can. Keep the can upright while filling.

 

So I got the hose right now, but I still haven't located the port. I found 2 potential things that could be it though. Here's the pics:

Pic 1

Pic 2

 

 

So I got another can and filled it with a little more, but the bubble seemed to disappear, so I took it off and put the cap back on the port. But there's something really weird about the bubbles, when the fan kicks into high speed, the bubbles return, when it's not at high speed, they go away and it looks like it goes completely empty. The air in the car is cold as can be, but it just looks weird. I made a video to show the issue and narrated it a little louder this time so you can hear me.

 

It's still low but cold air is cold air. I would wait and see if the cold air stays. If you have a R134a leak then you don't need to keep throwing good money at it by refilling the system. If it goes warm again then it's time to get a shop to pinpoint the leak and fix it. If it stays cold then consider adding more refrigerant until all the bubbles disappear. It doesn't really hurt anything to run low, your compressor just cycles more.

 

With the amount of corrosion that I see in the photos, you likely have a leak at the condenser. The salt does a number on aluminum parts.

 

Where would the condenser be and what does it look like? It hasn't gotten warmer for about a week or 2 since I first filled it, so I added more the other day and the bubbles seemed to have disappeared, so I don't think there's a leak, but I'd still like to learn more.

Also, looking at my engine bay, it's very obvious that everything is very dirty and corroded. I don't know how badly it might affect them, but the corrosion on almost every metal surface looks really bad to my untrained eye. Is there any way to clean everything up and somewhat restore it to a cleaner and/or less corroded state without replacing parts? How long does it look like it can go on like this? This is only supposed to be a beater first car for me, but I want to take care of it and make sure it lasts for a while and doesn't give me issues.

I watched on cleaning engine bays and found it very nice and easy to follow and am wondering if everything in that video is okay for my car. Also, any other thoughts for what I should do for general maintenance and stuff like that?

Thanks.

 

The condenser is a radiator for the R134a. It sits between the outer air/air intercooler and the inner coolant radiator at the front of the engine bay. It's purpose is to condense the hot high pressure gas coming from the compressor into a cool liquid that flows into your receiver/drier. That's where the bubbles come from as too low a charge means not all of the R134a turns back into liquid.

You can clean the engine bay like any other car. Just go slow and try not to spray high pressure water at your electrical connections. I would remove the battery. Really though, who is going to see it other than you?