Hi guys,

It reached 93 here today and it has always taken too long for my AC to reach a cool temperature. I have never had the AUTO setting slow the fan down even at highway speeds. I am moving to TX in the next few months and I already know what it is like driving it down there...HOT! I could really use your help on improving the efficiency of the AC of my Ex.

Can I use the same insulation used for home AC lines on the truck? Is there any high-temp insulation I could fun over the lines to help? I found a coolant shut-off valve for the heater core on 7.3 trucks, but not for the 6.0. Is there an equivalent for us with the 6.0?

I appreciate any and all help I can get from you all.

p.s.
I just had the system evac'd tested and recharged last week.

Thanks,
Sam

 

Take a look under the hood back by the firewall on the passenger side. One of the heater hoses might have a valve hooked up to a vacuum line. My '05 has the valve. I think the one that dieselsite sells for the 7.3 looks like the same thing I have.

Do you have much airflow from the vents? I know I've had cars that had the core clog. That caused two problems. First, the crap on the fins wouldn't cool the air. Second, after a while the crap blocked the air and I didn't get much airflow.

 

Do you get cooler air out of the rear vents vs. the fronts? I just removed a potato chip back from a customer truck the other day - not only was it blocking the air but was making an awful racket as well. I agree with Jeff though - check the valve at the heater core to ensure it is hooked up. If the hot water isn't blocked off it significantly reduces the AC effectiveness.

 

Also look into getting a snow plow fan clutch. Some guys from AZ say it runs the A/C cooler by pulling more air thru at lower speeds. I needed a clutch and went ahead and went with the snow plow version. hasn't gotten hot tnough to notice a difference really. I think the A/C is cooler, but will really know whne we break into the 90's soon.

 

What are your vent temps at highway speed? What are they at idle?

 

Thanks guys! The temps seem to be pretty similar between the front and rear. Also, the airflow is fine. The temps between idle and highway are much different; I don't know what the numbers are, but I can tell a huge difference between the two. I like the idea of the snow plow fan. I will look into that and I will also check to see if there is a valve like mentioned.

Thanks again and please keep them coming! I'll get back to you with any additional info I come up with.

 

I just checked and I do have the valve. It also seems to function when I turn the AC on. I left it to idle for about 5 minutes and I don't think the air was blowing any colder than 70 degrees. It is 90 here right now and this was the first time the truck was on for the day. I think the air is closer to 50 degrees when cruising at highway speeds.

I noticed a hissing sound from the passenger side near the firewall when I shut it off. Is that typical or something that sounds like I should look into?

Thanks again, everyone!

 

It's possible your recirc is not working. Also, as others mentioned a more aggressive fan clutch will help draw more air through the condensor and may help vent temps. A larger condensor would help vent temps also, some Super Duty's are shipped to the middle East, they may have larger condensors but may have to adapt the fittings. Another possibility is changing your water pump pulley to spin the pump/fan faster. I don't know what diesel has for pulleys (I know gas).

 

Sam,

You should have your A/C system check/tested.
It might be low on refrigerant thus not able to cool appropriately.

Also, there is an additive they can add to increase the
heat transfer (blue something I think - used it on my prior vehicle)

It's been in the low 90s here lately, I also have the Bulletproof Oil
Cooler mounted to my A/C condensor and I have had no problems
with A/C temps, idle or hi-way it's still very cold.

I have the vacuum activated coolant flow valve on the heater line.

 

Hey guys I was wondering if the 6.8 liter V-10 has that valve you guys are talking about. I also have the same problem, it takes My excursion a while to finally cool down on over 90 degree days. I'm in Miami and it's really starting to Heat up down here.

 

I thought all Excursions have the factory shut-off valve as do the Lariat trucks. Just follow the hoses to the heater core in firewall - you'll know a valve if ya see one (also has a small vac hose running to it).

Put a MANUAL (1/4 turn ball valve) on the SUPPLY to the heater core(s). I close the valve on my F350 all the way in summer months - big improvement! The factory shut-off only works when A/C is in MAX setting IIRC and it is also on the RETURN side of the heater cores - so they still get HOT after driving for awhile...

If you open the AC system up for ANY reason at all, I recommend the 38639 (IIRC!!) orifice tube. I installed this in my F350 a few years ago and never looked back! I replaced the condensor and orifice tube in my X last summer and had 37* air at the vents on a 100* day. My kids had the nerve to complain they were COLD!! It was actually the coooooldest when sitting still with 1100rpm idle turned on - I'd guess because coolant temp and flow is the lowest at idle... (I do not have any 'extra' valves on heater cores - YET) Then, the gas all leaked out at the line-set to condensor connection and I still haven't been able to determine why (I actually let someone else do the work - guess that'll teach me ).

 

Take your X to a good AC shop where they have a HVAC machine that can remove the R-134a, pull a vacuum, insert a leak detecting dye when they recharge and check for leaks a couple of weeks later after you run the system.

I got my '04 X in 05. In the Spring of 08, the AC air was hot. Took it to Midas (good HVAC shop) and they did all of the above and found no leaks. They had to add 1.75 lbs of R-134a.

Last week I noticed the AC air was not cool. So I took it to the same Midas shop and they did all the above again. This time they added 1.5 lbs of R-134a and it is nice and cold.

So looks like every 3 years I have to get my AC recharged. I can live with that.

DSMMH

 

Over time, the condensers can lose effectiveness due to dirt, dust, bugs, and other contamination.

Take a can of non-acid (detergent based) coil cleaner and spray it thoroughly over the condenser. Let sit for a few minutes, and rinse thoroughly with the water hose. If any of the coil appears impacted with dirt you can use a soft bristle brush to get the cleaner into the clog(s).

I do this to my Ex, truck, car, and house annually. The result is that they never work just "OK". It blows cold (34-38*) or it's broken.

 

They must love you! Sounds to me like first of all, they never found your leak and secondly they charge you to evacuate and recharge the system instead of just putting a set of gauges on it and adding some gas (which you can easily do yourself for under $20).

I don't know your whole story, but my experience with that chain has always been similar - they rip off the unknowing, but often do a great job of making them feel good about it. Usually its brake work, I've had a few experiences with friends and family where they were quoted ridiculous prices and were scared into thinking they MUST have all of this done or they will crash. When confronted, they always back down and the paperwork/quote shows most of the work as 'recommended' (ie, new brake hoses, calipers, etc). I am not a fan of chains like this... Rant over!

A/C is such a big mystery to most people. It is really not that complicated and just involves nuts, bolts and parts like everything else under the hood. Yeah, ya need a vacuum pump and a 'real' set of gauges are nice - but at least knowing WHAT they are doing and WHY will save you from being ripped off at the shop.

 

Thanks for all your help guys. I did have it tested and it was about 2 lbs low, which is why it wasn't working earlier this Spring. They put oil and dye in it to find any leaks if I have any more problems. Unfortunately, I think the problem I have is not a leak. I've noticed ice cold air today with the outside temps down around 70-80 while on the interstate, but once again it starts to get pretty warm once I'm in traffic.

Jason, that is a good idea about cutting off the supply to the heater core. I will look into that to help. I typically run the AC on max at all times because it is insufficient at any other setting.

What is this orifice tube you are talking about?

BassFantasizer, I'll get some of that cleaner and see if I can spruce it up some!

I've also been considering getting a flex fan. Do you guys think it would be better than the plow clutch at pushing air when in traffic?

THanks!!!