Cavalier uss-8-64 Only the bottom few rows stay cold ?????

[bpoe1321]

I have a fairly nice condition uss-8-64 located inside my business showroom.  I bought it in 2011 and installed a complete new cooling system at that time.  It has worked perfect since then.  No issues.  The temp dial has remained on about 4 all this time.  about 5 days ago, I noticed the top few rows were not cold at all, very slight cool would be a generous description.  The bottom few rows were nice and cold like always.  The compressor is running the fans, inside and out, are turning fine.  I found a little ice under the coils on the evaporator, but nothing major.  I opened the door and unplugged, just to let thaw and make sure.  The evaporator is blowing fine and cold enough that when I am sitting with my face in front of it, trying to figure this out, I can see my breath.

It's almost like the back wall is blocked and the air is not flowing up it to the top.  But it is free of obstructions.  And even then, it should cool the entire insides, I would think.  I have checked the gaskets and the vend door.  Nothing has changed, all seals seem good.

Help.

[Slapshot42]

Is the fan behind the evaporator working?

[bpoe1321]

Yep all fans working.  When I place my hand near it, I can feel the cold, not cool,  but nice and cold air blowing pretty good.  But it just doesn't seem to be forcing its way up the back of the machine to the upper shelves.

[Slapshot42]

Have you tried adjusting a thermostat to a lower setting?  Do you have a thermometer to check how cold it's getting?  Is the compressor cycling on and off?  You could of multiple variables going on.

[bpoe1321]

I tried adjusting the temp dial from #4 to #3 ( a little cooler)  It didn't change anything.  Still nice and cold on the bottom few rows and warm up top.  It's just plain weird.  Everything is cycling as it should.

[Creighton]

Fan motors may be wearing out. Bunch of dirt on the blades not ideal. Another thing could be dust buildup in the cooling fins. Worn out door seal in the mix as well.
Hope you get it sorted. Photo's always help.
Creighton

[bpoe1321]

Thanks.  Will post some pics asap.  Fins are good.  Fan motor wearing out sounds like a winner because I can place my hand at the back wall above the top shelve and hardly feel any air movement being pushed up to the top.  But the fan is running and seems to be spinning at a pretty good rate, but is it full speed?  That I dont know.  My uss-12-96 at home blows air to the top very well and hard.  not sure if that fan is a replaceable part or not.  I will check.

[MoonDawg]

        Fan is replaceable but first try pouring a little oil down the shaft of the motor.
 

[bpoe1321]

I let it sit, unplugged over the weekend and plugged it back in Monday morning.  It cooled great, top to bottom.  Then yesterday afternoon it started to get less cold on the upper shelves again.  There seems to be an abundance of water/moisture on the bottom of the radiator ( i know that may not be the right word) on the inside unit.

[MoonDawg]

  It cooled great, top to bottom.  Then yesterday afternoon it started to get less cold

       You must have some moisture in the line. It flows along with the freon until it forms into a drop of water
that freezes into ice and blocks the line. When it's shut off, the ice melts and the system cools again.