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Help Cleaning A/C Evaporator in Kubota SVL-75

Derek M

Member
Joined
May 16, 2020
Messages
6
Location
Nebraska
Have a SVL-75. A/C blows cold air, but the airflow is about like a baby blowing out a candle. Filters are replaced, cleaned, etc. They're not the issue. Guessing the evaporator is plugged and restricting the air passing through. Pulled the seat, back panel, nuts, screws, and so on, still can't access the evaporator (which seems to be sealed in an impenetrable vault between the heater core and the blower motor). Can visually see the heater core and it is clean on both sides, but it is after the evaporator, so I need to get the the inlet side of the evaporator where I expect to find it plugged.

Many who post on the subject say they've cleaned it, but no real details on how to get to it. Hoping not to have to pull all the refrigerant lines, etc. Any help would be greatly appreciated!
 

Derek M

Member
Joined
May 16, 2020
Messages
6
Location
Nebraska
Thank you for the reply. Still a lost babe in the woods...

Here is a photo of the front and top of the HVAC unit behind my seat. Intake / Blower on the left, then Evaporator, then Heater Core.

The little open box looking down from the top is where the evaporator is located, but there's as plastic piece just below that opening that prevents any visual or physical inspection.

When you say top cover, and upper vertical cover, what are you referring to?

Front 2.jpg Top.jpg
 

Legdoc

Senior Member
Joined
Oct 6, 2007
Messages
464
Location
south texas
Same problem with my SVL-90. I did not want to go to the point of breaking the refrigeration lines with a full takedown of the case. My solution worked very well. I went to NAPA and got a 1/4" brake line and bent a tight 90 in it and adapted the other end to a rubber hose then transitioned to a water hose. I contoured the brake line as needed and thoroughly flushed the evaporator core toward the fan with the drain hoses placed inside a shop vac hose. Due to the volume of water some leaked out of the case. you can't imagine how much crap came out. The air flow is much better. This winter I plan to carefully holesaw the top of the case just left of the evaporator to drop a suction directly in for better evacuation and flush it again. I completely washed down the back inside of the machine and wiped it clean. On assembly I used a wide foam tape to seal the plastic to the metal.
 

highwayghost

Senior Member
Joined
Nov 1, 2019
Messages
315
Location
Pittsburgh, PA
Occupation
Emissions Analyst
This winter I plan to carefully holesaw the top of the case
Use caution, I have put holes in a couple A/C's trying to drill near (you would think I learned on the first one:oops:). The drill sucked in as the hole was near finished. Use a depth stop on the bit.
 

Derek M

Member
Joined
May 16, 2020
Messages
6
Location
Nebraska
Same problem with my SVL-90. I did not want to go to the point of breaking the refrigeration lines with a full takedown of the case. My solution worked very well. I went to NAPA and got a 1/4" brake line and bent a tight 90 in it and adapted the other end to a rubber hose then transitioned to a water hose. I contoured the brake line as needed and thoroughly flushed the evaporator core toward the fan with the drain hoses placed inside a shop vac hose. Due to the volume of water some leaked out of the case. you can't imagine how much crap came out. The air flow is much better. This winter I plan to carefully holesaw the top of the case just left of the evaporator to drop a suction directly in for better evacuation and flush it again. I completely washed down the back inside of the machine and wiped it clean. On assembly I used a wide foam tape to seal the plastic to the metal.

Thank you for taking the time to respond. I with you, except for how you got the water out of the sealed case that holds the evaporator?
 

Derek M

Member
Joined
May 16, 2020
Messages
6
Location
Nebraska
So, as a last ditch effort, I decided to roto-zip an access opening. Wasn't sure if there was anything behind the plastic, so I set it just deep enough to cut through (nothing behind). Once I had it opened up, I discovered an evaporator that was all but completely plugged up with gunk. Anywhere from 1/4" to 3/8" thick! Hard to get any air through that.

dirty.jpg

Carefully vacuumed it out first, then putty knifed it, then to get the smaller stuff, we used compressed air on one side with a strong vacuum on the other.
Cleaning.jpg
Looks pretty good now, but would still like to flush it with water. Airflow increased exponentially.
Clean.jpg

Then just sealed it up with Foil HVAC tape...
Taped.jpg
Nice thing is now I don't need to pull the seat and all the other hardware to get at it. Just the top and back cover, cut the tape off, and there she is. Seems like Kubota should have designed it with an access panel to clean it out.
 

Trashman

Well-Known Member
Joined
Jun 9, 2008
Messages
216
Location
Texas
Occupation
Garboligist
You can by a foaming cleaner at Home Depot to clean AC evaporators. Melts the gunk right off.
 

Legdoc

Senior Member
Joined
Oct 6, 2007
Messages
464
Location
south texas
Good job! It is certainly a poor design. Make sure you seal the covers well to the metal as the foam does not seal well and bypasses the filter.
 

Reuben Frazier

Well-Known Member
Joined
Mar 25, 2019
Messages
145
Location
NE Texas
That looks like a pain in the rear lol, the cleaner from Home Depot works really good though for future use.

You may opt to clean the filters a little more often to o_O
 

heymccall

Senior Member
Joined
Feb 19, 2007
Messages
5,349
Location
White Oak, Pa
You may opt to clean the filters a little more often to o_O
Yea, good luck with that. It ain't the filter media, or even plugged filter media. It's the fact that the air inlet to the HVAC box isn't connected directly to the filter housing.
 
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Dvd

New Member
Joined
Jun 11, 2021
Messages
1
Location
Texas
We just did the same thing with ours. I used a razor blade to cut the plastic, used a whole can of foaming coil cleaner, used a 90* air nozzle from the heater core side, and blew it out. All I had around was 4” PCV Pipe wrap tape to cover it. We will see how it holds. Air flow is MUCH BETTER. I also taped up the air intake from the exterior where it will only recirculate air. We will see if that works out or not.
 

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Hard_Yakka

New Member
Joined
Apr 22, 2021
Messages
2
Location
Oregon
I have the workshop manual and have looked over the separate section on the A/C .. don't quite understand the one illustration and the machine is not here for me to go look at. One set of bolts are accessed from inside the cab but the other set looks like you have to lift the cab to get at?
I blocked up my external intake earlier but it was too late my air flow is horrible to non-existent. Horrible positive pressure system along with a host of other issues ... not made for prime time forestry IMHO after 1000 hours.
 

carletal

New Member
Joined
Jul 13, 2022
Messages
1
Location
usa
Others have written in this forum about drilling an inspection and irrigation/cleaning port in the casing to the left of the evaporator coil. I found that with that, though a fantastic improvement in access to cleaning the evaporator, I still wasn't happy with the time and effort to remove the outer covers to get at the cleaning port and the lower drainage drilled port. I improved on the design with a simple installed "up-pipe" that comes from the original hole in the lower casing through the outer casing. Installing a 1 ¼" galvanized pipe nipple makes access instantaneous. My clean out was with a garden hose only and worked great, though a pipe with 90 degree shooting side holes will be my next project. I also found that the drilling the lower drainage hole is not needed, as there is a condensation drainage hole lower in the stock casing that works adequately to drain the irrigation water. I also taped off the inside of the outside air entry fins, since I am working in very dusty conditions and with the current heat, use recirc anyway. Thanks to those that originally posted this solution and maybe Kubota will eventually improve this terrible design of HVAC ! (my machine is a 95 s-2.)
 

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