We frequently see folks dealing with over heating issues, etc. Certainly
there can be many underlying causes. Yesterday, I had 2 issues that shared a
common cause and cure.
My 3 cylinder diesel Kubota lawn tractor has been running hot. And, it seems
it has run hotter and hotter. to the point where I couldn't do any heavy
cutting for any length of time. The radiator sits at the back of the motor,
under the dashboard. There's a removable screen/grille under the dash. In
the past, I've removed that, and discovered the radiator fairly packed with
dandelion seeds & spores, etc. Cleaning that would somewhat improve but not
cure the issue. I looked at the engine side, and discovered a removable
screen I hadn't noticed before. Removing that unearthed a whole other
collection of packed debris and swarf between it and the radiator. Hitting
it with compressed air, and cleaning it out totally solved my over heating
issue. I cut tall wet grass all day in 85 degree weather, and the gauge
never got out of the low side of the normal range.
Later, I was dealing with the AC on my black Dodge diesel dually. The AC had
been kind of weak since I got it in 2003, but I attributed it to being a
large black vehicle. Well, end of last year, it ceased cooling at all. I had
a guy come out to the shop yesterday, and we vacuumed the system down, added
dye, and charged it back up. Surprisingly, it's a fairly small system. takes
only 1.8 lbs. As we charged it, the pressure on the high side just shot up
over 300lbs. An inspection revealed that between the AC condenser and turbo
intercooler, and in front of the radiator, was packed with mung and swarf.
Although it was a tight space to get into, compressed air, followed by a
degreaser, and water cleaned the area out. The high side pressure returned
to normal, and ultimately we were able to achieve temperatures inside the
truck at the vent of 31 degrees. I like AC that blows cold enough to hang
meat in.
So, while we often chase a variety of causes, sometimes we forget the simple
heat transfer causes and effect of the operation. In both cases above, the
cooling fins were just inhibited by debris from accomplishing their designed
goal.
Wm. Severin Thompson
~iii<O
<mailto:wsthompson@thicko.com> wsthompson@thicko.com
<http://www.thicko.com/> www.thicko.com
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