Truck A/C System

Truck A/C System

All indicators say good!

HERO Maker
07 July 2010
09:37 AM
Last summer, I could have hung meat in the sleeper, it worked so well.

Not so much right now.  Just checked everything, pressure level was in mid good range, took it to high good range.  Module on truck firewall says no problem!  Compressor is operating!

Wondering if any of you have had any problem with the slide temp control on the dash.  About the only time we have moved it was this past winter in the RGV.  Yes it got cold!  Moved it up off the bottom for some heat, but now doesn't' seem to be cooling much anymore.  Is there something on this control that can become loose (to make less tight; slacken or relax) , not allowing it to be slid all the way to close whatever if closes or opens whatever it opens?

Thanks for the help,

By the way, Volvo evacuated the system, April '09, filled it (they claimed it wasn't completely full), tested for leaks (none), and everything worked fine.?????
Thanks,

SIBERNUT
07 July 2010
11:16 AM
I know this is stupid, but- Volvo AC won't turn on unless you start the fan first, then hit the AC button.
D K.
07 July 2010
11:53 AM
The only way to know if the system is truly full is to completely evacuate it, then refill it.  You can get a guesstimate off of the hi/lo pressure readings on a set of gauges and temp readings, but to guarantee you are at true factory spec, it has to be drawn down.  A dealership will have a recovery machine, so unless they discounted the R-134 accordingly to what they pulled out, you charged you for your own gas when they reintroduced it back into the truck. (The new machines will capture all the gas, filter it to remove sealant/dye, then place it back into the next charged vehicle.

Most of the sleeper units I've worked on had an air operated valve for the bunk, is it just the bunk you are not getting cold air from or is it the dash as well?  The selectors are different between them. (One of the reasons most drivers place heater core 1/4 valves on the coolant ports so that bunk valve doesn't stick and cook you out of the back while the dash is icing up).

HERO Maker
07 July 2010
12:54 PM
Sibernut
Well that is interesting, and when I read your comment a 2nd time, saw the "then" you had underlined.  So I guess you are saying I should be shutting off the A/C when I am shutting down the truck (never did in any of my cars) and then turn the fan on and hit the A/C button after starting the truck?  I will try that and see if there is a difference next week.
Thanks,
HERO Maker
07 July 2010
01:06 PM
Dave K,
Both sleeper and dash are not pushing cold air.  Thought maybe the slide was sticking and not allowing max cool.  Doesn't the slide need to be on max cool for the sleeper to work, or because it has it's own system then it doesn't need dash air to function?

Thanks for the help.

It sounds like either the pressure test they gave it didn't work, or it has developed a small leak since.

A couple of OTR guys said "to just throw a couple of Wal-Mart cans of R-134 into it and it will get you through the season."

It wouldn't even take a whole can!

Toterman
07 July 2010
01:34 PM
That's interesting!  You don't want to overcharge the system.  Does the compressor cycle on and off while you have everything on?  With all the controls over to the left, the little AC button pushed in you can cycle the AC on and off by turning the fan control to off and then number one.  My system was great for two summers and then I had to draw it down and recharge it last fall.  It's been working great all summer.  In fact it was 102 outside yesterday and I had her chilled down for hanging meat inside all the way home !!

Too bad your not over this way I have a system you just hook up dial in how much R-134 it takes and hit the go button and come back in an hour and its all done.
JMHO
David

D K.
07 July 2010
01:59 PM
If the system has leaked down for a while, it can end up with atmospheric air in it, which will prevent you from adding additional R-134 to the system.  The only way to get the system to hold the full amount of required refrigerant is to put it under vacuum to ensure it is void of all moisture.  The OTR guys you spoke to need to get back behind the wheel and leave that hood latch alone, I've made a lot of money off shade tree "mechanics" and drivers who just force another can into the system.  As David remarked, that is not the solution.  You can usually get lucky 1 time and introduce about 1/2 a can of PURE R-134 into the system before it ends up over pressurized due to the moisture and contaminated air being forced to compress, (which it won't) after that you wasting you money and likely risking the chance of water vapor icing up inside the evaporator etc.

You've already tried the can trick, now it's time to take it to a shop and have them check for a leak.  I do NOT recommend letting them put sealant or dye into the system, I do not use that stuff, especially the all-in-one leak stop dye.  A good A/C tech will have a sniffer or gas detector that they can locate the leak with.  Dye does work, but rarely is it really necessary, the leaks are nearly always at a line connection/O-ring or the test port Schrader valves.

I'm happy to help if I end up along your travels sometime

HERO Maker
08 July 2010
12:38 PM
To the Davids, thanks.

I will take it to the shop to get the real thing done somewhere along the road.

Wouldn't you know it, left the RGV, Volvo there - $150 includes R-134, Volvo repair in Tyler - $235 does not include R-134!  Not driving back to Mission, so will search the road.
Thanks again guys

D and J
08 July 2010
01:48 PM
Hey Rocky, (and others)

Isn't air conditioning basically all the same no matter what it is installed into??

What I mean is, you don't have to have this done at Volvo, any shop that had a door large enough should be able to diagnose and fix the problem, right??
Doug

D and J
11 July 2010
02:51 PM
No comments on this???

I would really like to know if I had a problem, if I have to seek out a HDT truck service center, or not.

Barncats
11 July 2010
03:11 PM
I had mine looked at and charged at a regular auto shop once.

My AC went on the blink this season and it turned out to be the clutch on the compressor.  They realized this after they installed a new compressor and used the old clutch assembly and took a bunch of cash from me. Didn't even make it home and it stopped blowing cold air.

Needless to say, I was not a happy camper

SIBERNUT
11 July 2010
03:13 PM
All current A/C systems can be serviced by anyone with the proper equipment.  The only thing they need to know is the system capacity, which is usually displayed on the compressor or close to the charging connection.  See if yours is, if not do a search thru your owner's manual or call Volvo.
Mike Council
12 July 2010
10:11 AM
After countless hours of research I discovered, from an uncirculated Volvo corporate email which had to be translated from Swedish, that the air conditioner adjustment slide lever was actually a very well disguised part of the driver entertainment package!  It is actually an On/Off switch!  Oh, if you play with it too much you will go blind.
Mike
J.W. Morgan
12 July 2010
07:23 PM
I can think of at least one shop that does not have a door big enough for a Volvo that works on A/C's.\

Sorry though there is no "recycled" refrigerant here though, its cheaper to replace than owning the machine.

HERO Maker
14 July 2010
04:10 PM
OK Mike. That is interesting!

Today, I placed the DW in the cab so I could see what was happening to the compressor clutch when the A/C was turned off and on.  Yes it did function correctly.  But when I had her slide the temp control from cold to hot - it quickly got hot (isn't she sweet?) but the compressor clutch never stopped????  Isn't it supposed to when there is not demand for cool air?  This might follow your comment about the "switch".
Thanks guys,

Rif
14 July 2010
07:10 PM
I believe the heat control slider only mixes hot air into the cold air stream by turning on the heater.  This is the way most A/C systems work.  The compressor never shuts off until you turn it off.

By the way, the compressor comes on automatically whenever you slide the directional control to defrost, even if you don't press the compressor button.  It does this so the air being directed at the inside of the windshield is dehumidified.

D K.
14 July 2010
08:38 PM
The A/C system used in conjunction with the heater core works well to dehumidify the cab.  When you are in the deep south in the winter, getting that cold damp air out of the cab is even more comforting than just heater warming it up to hot wet air
HERO Maker
15 July 2010
10:23 PM
Good info guys, thanks.

Started out leaving East Texas today, now in Denton.  It was a hot afternoon and the truck just barely cooled the cab.  Will have someone look at it in the morning.  Pricing here is worse than in Tyler!  DFW just added another $100 to do what they would do in Tyler!  And that was $75 plus cost of Freon higher than Pharr, TX.

Ok well, it's only money!  But I really need to be cooler going down the road.
Will let you know what they find.

Rif
16 July 2010
08:06 AM
Rocky,
I have used Inland, just down the street from the TA.  They did some A/C work for me a couple years ago.  They've always treated me fairly with everything I have had done there.  Since we spend a couple months each year in Denton while visiting my daughter, I tell them that I am in no hurry to get the truck back and that they can just work it in around other more pressing jobs in exchange for a break on the cost.  That's just what they've done
HERO Maker
16 July 2010
09:39 PM
Thanks Rif.
I had already headed out before your posting.  I used Bobby at J & M Automotive on 77 in Denton.  Stand up guy.  This wasn't a show type shop, this was a lot of work getting done here.  Bobby took care of me,
slipping me in right away.

Result.  Really low on Freon.  That means I have a slow leak.  Will be searching for it, but should last the summer and into the fall.

Thanks for all the help guys.  Now the rest of the fun continues,

Bill R
19 July 2010
12:27 PM
I had to get my A/C system charged about every year or so.  It passed all the tests (pump down and hold and dye) and showed no leaks.  Finally it was mentioned to me that the service man thought he had seen or heard a leak from one of the Schrader valves (like tire valves that are beefed up for A/C) (none in stock).  Last month I had both of them replaced and the system recharged.  This makes sense to because the valves are NOT holding the Freon back when the A/C machine lines are hooked up.  Seals are sealing when lines disconnected.  I have a sticker that identifies how much Freon is to be put in for various cabs, mine is 610.  The A/C tech also stated that an oily coating with dirt embedded on the front of the clutch would indicate a leak in that area.  Mine was ok
D K.
19 July 2010
12:53 PM
Very good point to bring up Bill.  This is a lot more common than some may think, you can usually watch for this yourself by looking for the same oil & dirt staining on the hi/lo ports.  You can unscrew the test port caps just like a valve stem cover, no need to worry about the high pressure gas unless you play with the Schrader valve itself.  (Which is much higher pressure than a tire, so don't try to reseat it like a tire valve by poking it with a pick or valve stem tool unless you know what you're doing)  The rubber seating on the Schraders wear out just like a tire valve's, but rarely are replaced as often as tires over the life of a vehicle.  These ports can seep intermittently without a visible indicator unless you have dye or a Freon detector.  Make sure you have the system tested with the a/c on in case it is a high pressure only seepage.  Disabling the fan to prevent air blowing and dispersing a small leak helps a lot.  I prefer not to use dye, so checking for leaks can be a bit difficult with the fan blowing on you, not to mention dangerous to be working next to.
D K.
19 July 2010
02:31 PM
This video is fairly good to give you an idea of what a tech is going to do, or should be doing: Charging and Evacuating A/C systems part 1
HERO Maker
19 July 2010
10:12 PM
Great stuff Dave.
Now setting in Custer, South Dakota, and the temp is fantastic!  Didn't even use the air in the last few hundred miles getting here.  Nice to be out of the RGV and East Texas heat and humidity.

Looking forward to learning more about this truck. You folks are a great help.
Bless y'all

Jack Mayer
20 July 2010
10:36 AM
Rocky
Don't feel too bad - I have a similar problem, coolant is not holding in my system.  It worked fine for 5 years.  Then Jim's guys fixed it and it worked fine again for a couple of years.  Now it is not holding coolant.  So I'll tackle that when we get back to Woodland Park, we are on "vacation" in Buena Vista (jeeping).
Hogrydr
20 July 2010
04:38 PM
Jack probably compressor seal.  That's usually my kind of luck ....
Jack Mayer
20 July 2010
06:24 PM
I hope not Jim, but I was thinking along the same lines.  I'm willing to invest the $$.  I just want cool air.  It has been unseasonably hot in the Springs.  Going down there in 95* heat (even if it is only 30% humidity) is not fun.
D K.
220 July 2010
10:44 PM
It's 80 degrees and 40% here, (In my garage with 2 portable A/C's running) 103 outside probably over 60%,  I'd take a buller for you and swap the pump if you were down here though Jack
HERO Maker
15 April 2011
01:53 PM
Well, it's that time of the season again.  Time to get going.  But again the A/C is not keeping things (me and DW) cool.  I'm being told it is the front seal on the compressor.  Is this something I can change out, or do I need to replace the whole compressor.  I understand that I should also replace the dryer at the same time.  Have some time in front of me, in a cooler spot, so might attack it.
Thanks,
Jeff- C IL
15 April 2011
05:45 PM
My guess is they will insist on Reman exchange on the compressor.  I've never heard of being able to actually change a seal DIY on these.  Then you get to go thru 3 or so remans to get one that actually holds Freon for more than a month.  I'm pessimistic about reman A/C compressors since I put 3 in a row on my DT466 and still don't have A/C - I finally gave up.  Work for 2 months than quit.  The rest of the system checked OK, just the compressor front seals kept going bad.

Sure hope your experience is better than mine -- but you may want to buy "new" or OEM or a better grade reman if possible.  Also look and see how long the warranty covers, and if it provides labor to replace it during that time

J.W. Morgan
15 April 2011
07:54 PM
Jeff,
I would seriously look at the pulleys and mounting brackets on your DT466, I have installed quite a few Reman compressors with very good results.  Keep in mind it is possible to get a belt "too" tight and cause premature bearing failure.

Rocky,
That is NOT a DIY project, just go find a quality reman or keep dumping Freon in it, I have chosen the latter on some of my personal trucks, since it is really easy for me to add the proper amount every spring

Jeff- C IL
16 April 2011
09:24 AM
Thanks, JW
That may indeed be part of the problem, as at that time I was using the "extra" pulley on the AC to run a hydraulic pump that ran a hydraulic sprayer pump.  This was actually a common option on the 4386 type
tractors - could even be factory ordered I believe.  The problem was that if you ran BOTH the hydraulic and the A/C at once you'd fry the belt from the Fan pulley in a week - thus the REAL tight belt, etc.

On the other hand, the problem might have been the LOUSY quality of remans C-IH was getting at that time - lowest bidder wins sort of thing.  Let's see, 3-4 alternators with an average life of 2 weeks (I finally rebuilt one myself out of old parts laying around that is still on the tractor!),  the injection pump that was set 17 degree out of time internally and ruined a rebuilt motor, 3 A/C compressors, 2 torque Amplifiers that the welds failed, you get the idea.  I quit on the A/C when the service tech said it was normal to go thru a couple before getting a good one.

On another thought--you aren't gonna be up in IL and want to install a Pac-brake, are you?

J.W. Morgan
16 April 2011
02:06 PM
No on the Pac-Brake, you can handle it!  Also you are not buying those compressors from the tractor dealer are you?
Darryl&Rita
16 April 2011
06:35 PM
Pac-Brake is a piece cake.  I did ours last summer, on the Dodge, in a morning, finished the compressor install in the afternoon.  They have a GREAT customer service line, don't be scared to use it, if needed
HERO Maker
17 April 2011
09:50 PM
Left the RGV today in not very hot temps, but the A/C didn't work all that well.  But as I got a little further north (still lower half of Texas (5 hour drive)) we actually had to adjust the cold setting a little warmer and turn the fan down a bit!!  I know it wasn't that hot outside, but it sure was cranking it out and making it colder inside.

Will wait and see as we leave here later this coming week.  Will probably look at replacing something while we are in the Tyler TX area.

Thanks for all the comments guys,

davelinde
21 April 2011
08:41 AM
Here's my AC story so far.  When I bought the truck I was told the AC leaked down very slowly and might need a charge annually.  The AC did, in fact, work fine for the first 3 or 4 months.  Then it stopped blowing cold and tripped the computer from green to red on the firewall.  I put a can of R-134A in and all was good again.  A few months later, no AC.  We had no travel plans so I let it sit for a few months.  This week I put a second can of R-134A into it and brought it to the shop to be sniffed for leaks.  By the time I got there (the next morning 14 hours later) it had leaked down again.  Shop told me my compressor was "leaking like a sieve" -- so $600 later I have a new compressor/dryer.  Shop just called to say I had passed a vacuum test yesterday, then was pressurized and held
pressure over night.  So it seems all is good?

I am curious, if it had a slow leak at first can I HOPE it was in the compressor and now it's done?  Did pushing cans of R-134A into the leaking system break the compressor? I n other words -- how long can I expect to get cold air for my $600?

I'm also wondering how much premium I paid.  I had a choice of a local "backyard" mechanic (by which I mean, he's a full time pro but will do work in his home shop - and his home shop is big enough to park my Volvo inside!  He had a Class A in there when I last visited) or a big local shop.  I went with the big shop and paid $290 for a compressor/dryer and 3hrs @ 94 for the install (and diagnosis).  If this repair holds up I have no complaints, but I still don't like to over spend -- and pricing on Volvo repair is a mystery to me.

Jeff- C IL
21 April 2011
01:27 PM
Well I was, at the time I didn't know enough about "real trucks" to know where to go for crossover parts! (besides,  I only bought the first one!) I will say I never by reman stuff through any dealer anymore - unless its not available at the specialist shops.  And now I ONLY get injection parts from a diesel injection specialist I know, trust, and can go back to if I got problems.

And as for the Pac-Brake - its actually a PacBrake ENGINE Brake (like a Jake).  Goes on between the valve covers.  I'm assuming the Dodge application is actually a Exhaust Brake - or do they really make jakes for Dodges!!!???  I'm not too worried about installation, actually - just need to be careful to get valve clearances set correctly.  Wiring is not an issue, of course.  They want about $750 to install it at the dealer - so you know it can't be TOO hard!  I do apparently have to run the truck in and get the computer set to know it has a Jake on it--at least they "think" so.

Darryl&Rita
21 April 2011
01:52 PM
Sorry Jeff, exhaust brake.  They do make exhaust brakes for the motorhome set, for up to 300-330 Cat engines, but I forgot about the REAL engine brakes.  Insert forehead slap smiley.
Jeff- C IL
21 April 2011
04:13 PM
And here you had me wondering whether Pac-brake was making a REAL engine brake for the Cummins!  I know more than a few farmers who will NEED an engine brake on their PU if it keeps raining much longer!  I don't know all that much about it - Scrap got me the link to the guy who was selling these NIB on eBay - and it just happened to fit my specific N-14.  Basically pull the valve covers, install a riser block with "plunger" solenoids on it, adjust the clearance to the valve rockers, and put the covers back on top.  And then install the included wiring harnesses and switches.  It doesn't LOOK to hard - maybe easier than messing with exhaust pipes!  I'll take pictures. Sorry for stealing the thread - back to A/C
J.W. Morgan
21 April 2011
09:42 PM
Jeff reading your last post, when you said Pacbrake, I thought you meant for your pickup,  I would be glad to help you install an engine brake on an N-14, just bring it on down in a few weeks.
StraightTimeStirrups
22 April 2011
11:01 PM
I just had to put 3 pounds (out of 5 pound system capacity) in my truck.  Its basically been sitting for over 4 months without a start.  My friend is a Certified AC mechanic and he told me its best to run your AC Compressor at least every couple of weeks to keep your seals moist with the compressor oil contained within the system.  He also told me a quick test to do to see how well your system is working.  He said to stick a probe thermometer into one of the vents and run your fan on either of the two middle settings and a really good system will drop the ambient temp 40 and 50 degrees on an awesome system.  Any lower then 25 and you could probably use more Freon.