Ok I have been dealing with this smell in the cab for a while now. I cant seem to find it. It smells sorta sweet burnt. I do believe its antifreeze. So here is how it occurs.. On cold days it may only smell after about a 40 mile ride. On warm days like 40+ degrees it will start to smell after about 20 miles. I had the coolant system pressure tested (cold) and it held 18 lbs for 30 mins. So then I cleaned the motor and the valley really good. It is dry as a bone (3 weeks later) and I still get the smell. No leaks that I can find around the water pump or hoses either. This has been a mystery for me for about 4 months now. I don't get any steam on the inside of the windshield that would show a heater core leak. So my question it if anyone has had this issue and where else can I look or test. I was thinking it may still be the heater core, maybe the connections or a pinhole. The smell only happens after the truck heats up nicely. The warmer the day the wore it is. thanks Jeff

 

Did you do the colder A/C mod? I have gone through 2 valves so far.

 

I've not gone through valves with my own A/C mod, but I did find some loose hose clamps on the first winter after doing the mod. This could allow coolant to hit your hot exhaust and get fumes into the cab, especially in cold weather when you're running the heater.

Is your fluid level dropping at all over time? Even if your system passed the pressure test, it only takes a few drops of coolant on a hot exhaust to create an odor, and even one drop per minute would only be 30 drops in 30 minutes, which is just a tad more than one fluid ounce, and this very small change in fluid volume in your system would not necessarily result in enough of a pressure change to be detectable.

I only found my own leak while letting the truck run and watching the heater valve for about 5-10 minutes, and I eventually saw a drop ooze out of the hose and then knew what to do. Tightened the hose clamp and everything was good (until my water pump eventually blew out the main shaft seal some two years later).

 

Where is the link for this mod. my ac goes from cold to hot wile you drive and I just had the system checked and re-filled!

 

The link below is what I compiled on this mod a while back. Be patient, it's a 1 MB pdf file, but it has the history and functionality of the mod, links to vendors who either discuss it or sell kits to perform the mod, parts numbers for you to build your own kit and save a few dollars, as well as some discussions on various ways to do the install so that you have different options for applying the mod to your own personal taste. Hope it helps.

http://www.truck-mods.com/Air%20Cond...ff%20Valve.pdf

 

No, I Have not done that A/C mod so it is still stock. My next plan is to check the heater core and connectors. I just need see how to remove the cover behind the glove box. thanks

 

Yours sounds more like the air gap in the clutch needs adjusted.

SpringerPop's Compressor Clutch Air Gap

 

Thanks big Al.
when i get the truck back i will check the clutch gap and try this!! Thanks again!

 

Too wide of a clutch gap only affects how well the compressor will pull in to cool, and should have sbsolutely nothing to do with creating a sweet coolant odor in the cab. Coolant has to be leaking out somewhere.

 

I wasn't responding to the OP, apologies, I totally agree. Based on gdunn's post it sounded more like an air gap issue, sorry for the hijack

 

Alan, you're right, too. I had not noticed that you were not responding to the original issue either, and I have to agree that it sounds more like a gap setting on the A/C clutch for gdunn's situation.