Introduction
We have two mechanisms for dust infusion:
- vent plug leaking - possible but unobserved. There was some dirt but it was not clogged or showing evidence of inflow.
- gasket infusion - likly given the negitive internal pressure when cold.
This would tend to suck dirt in at any other
gap and the only ones are the engine gasket and front wheel drive shafts.
The proposed corrective action is to remove the plug cap and valve and run a
hose to air filter housing.
This would eliminate the negitive pressure differential at the risk of
filtered air being used to normalize the transaxle pressure.
Filtered air is only a relative term and highly dependent upon the
quality of filter and its maintenance.
To improve the quality of filtered air, we may fill part of the pressure
relief tube with cotton.
First Disconnect Power
As shown below, disconnect the 12 auxillary battery ground and
then remove the battery safety plug:
Remove Windshield Wipers and Upper Cowl Cover
This went fairly straight forward and was completed quickly.
Area Over Transaxle Vent Plug
Once the inverter is moved out of the way, about an hours work,
the aluminum brake assembly is visible in the center.
Just below is one of the inverter mounts and in front of it,
the pipe that feeds coolant to the cabin heater.
That pipe has a small electric motor that moves the coolant when
the engine is off:
This second shot shows more details including the cabin heating
hose and motor:
Transaxle Vent Plug
Located under the brake assembly between the rear of the transaxle and
the firewall, the 14 mm. transaxle vent plug is not easy to find.
In this photo, light comes from a flashlight and the heater hose
is moved to the side:
Transaxle Vent Plug Debre
The transaxle vent plug works like a one-way valve out. This allows heated
air to exhaust and when the transaxle cools, a partial vaccum forms.
As the plug was unscrewed, there was a 'hiss' of air flowing back into
the transaxle:
There was 'dirt' evident on the inside of the plug and
a cotton swab pickup up a couple of particles.
However, it was not clogged with dust.
Disassembly of the valve didn't show evidence of a
failure and the inrush of air indicated it was working:
Magnifier lense examination revealed the valve side had some small bumps and
lacked evidence of channeling. The compression pattern matched the
valve face which was slightly asymetrical.
Reassembly
The following photo shows the reworked transaxle breather vent.
The one-way valve has been replaced by a short, ~1.5 inch,
re-enforced PVC pipe held with a small clamp:
The breather vent is installed back on the transaxle.
There isn't much space and a short handled, flat, open-ended, 14 mm.
wrench would help installation:
For now, the breather tube runs to the other side of the air cleaner with
paper towels working as the filter.
We will run the rest of the week this way so any grit or dirt that might
have fallen in can be picked up and moved to the pan:
The last step is to install the air-filter tap and cut the breather tube to
fit.
Although there was a PVC tube, I was concerned that the crankcase gases might
include too much moisture.
So I installed a second vent at the front of the air cleaner.
