1994 W900L A/C issues

1. If only while traveling, door seals
2. If ac temp with blower on out vents in cab are good to roasting but not adequate to cool, your ac box is rotted out, replace with new box
Shoreline or jemali, do NOT buy a kw replacement, it will be more expensive and also rot out
3. If the blower is just not working/only at max, resistor on the pass side inside cab
4. If the blower is subpar... thats old kws for you.
5. Block off the outside air intake, the air operated valve doesnt really do that much

Its never just the expansion valve, sorry

 

Obvious place to start here. But have you checked the freeon levels? I know my pete had a similar issue when the system needed a recharge, cheap place to start at least.

Could also be a control module but im not a big kenworth guy. @OLDSKOOLERnWV might know? If not i know @W923 rebuilt that one W900. So he may know.

 

Checked the temperature position on heater dial?

 

While kws of that year lack a dial (Its a slider attached by essentially a bike brake cable), its entirely possible the valve never hits fully closed, most of that year have (non-factory) installed full shutoff valves to completely kill coolant flow to the heater core, even a trickle of heat in there can easily overpower the modest cooling the front unit provides especially if the box is on its last legs.

The refrigerant qty in the system is very unlikely to be the culprit because his sleeper is blowing cold. the sleeper and main box use a common high pressure low pressure line t tapped right under the main ac box in front.


Id still say inspect the main cab box in the engine compartment, if you dont have an upgraded to aluminum/stainless box, it is extremely likely that the box itself has so many holes and the cores are so full of dirt that it simply cant keep up /passes hot engine compartment air in.

Though making sure you have 0 coolant flow to the box is a big help too (when its cold out, the slider valve for heat also likes to not fully open the heater core valve resulting in subpar heating in 30 degree and under weather)

 

Thats a good call, i know you dont HAVE to get the platinum package (both cores, new blower exp valve etc) BUT, it would be far faster and a guaranteed fit.

When i did it on the w9, changing the box out took about 2.5 hrs, be prepared to cut off some existing bolts when they end up too rusted to do anything and a spare person to hold a bolt from cab to the engine compartment would be very handy but not neccessary.

Probably a 5hr job when adding in vaccing and filling plus cleanup after the fact if youre doing it in your yard/driveway.

iirc the fill should be between 3.5 and 4.1 lbs for a knox style compressor

Also if even if going with someone other than shoreline, they (shoreline) has a very good install video on youtube, think its linked on their site somewhere.

Watch it twice and keep it handy when replacing

 

Well I wish rebuilt was the correct word but it’s still going on…I haven’t gotten to the cab yet so idk about the ac…I might not even worry about it I spent my early 20s in southern il working on a farm and living in a house with no ac I was too tight to even have a window unit lol