Re: Mice & Air Filter
"Cornerman" <email@example.com> wrote in message
> Here's a twist of a question on the effects of mice nesting in the air
> filter. I just picked up a 92 Tercel for my daughter. It's got 80K
> miles, and runs pretty well. No odd noises. No blue smoke. I did a
> thorough break job (one leaking line, new rear shoes and turned drums,
> unstuck caliper slides), and put her (the little car) on the road. I am
> stunned how well this 14 year old car runs.
> We noticed that there was an aweful lot of pine needles and some pine
> pitch on the car, as well as some under the hood, so we figured it had
> been parked for a few months. It had a passing Massachusetts inspection
> in February, so at the very least, I know it ran then, and ran well
> enough to pass inspection.
> Anyway, we got around to cleaning the pine needles. And, as the title
> suggests, when I took out the air filter, not only was the air filter
> completely clogged with leaves and needles, but the entire air filter
> housing was filled to the top with nesting. We found two mice, one
> brown and one gray, quite dead. Some of the nesting was still green,
> which suggests the mice had been living up until recently.
> So... onto the odd questioning. How in the world did this little engine
> run so quietly and smoothly without sucking air through that air
> filter? It suggests that there are enough other air passages that don't
> go through any filter directly into the intake. I don't see anything in
> the air duct from the filter housing to the air intake that looks like
> it could possibly give enough air flow without the engine gasping for
> air. Instead of being elated that I found some source of a some poorly
> lean running engine (which I didn't seem to have), I'm actually nervous
> that the engine ran very well, despite a completely clogged filtered
> air source. No dark smoke, no gas smell.[/color]
There are 2 parts to the answer to your question.
First, as bad as the filter may have looked, it probably was not completely
clogged. You can confirm this by wrapping the filter in a plastic film like
Saran Wrap, replacing it, and then trying to start the car. The car
probably will not run with the plastic wrap encasing the filter. An air
leak in the plastic plumbing between the air filter and the throttle body
usually causes drivability problems.
Second, the air filter's area is relatively large for a 1.5 liter engine.
Take a look at the air filter for your daughter's Tercel, and compare it
with the filter for a Tundra with a 4.7 liter engine. The Tundra's
displacement is more than 3 times the displacement for the Tercel and so the
Tundra needs rougly 3 times as much air volume as the Tercel, yet the
Tundra's air filter is not 3 times as large as the Tercel's.
> Now I'm so paranoid that I'm sure every tink and rattle are acorns
> traversing their way to and through my cylinders. Oh the irony.
> So, what should I be looking for to make sure I'm alright (if I'm
> alright)? I suppose if I take the duct off the air intake and see
> grass/leaves that far, then I could be in some trouble.
I would not worry too much if a small amount of grass, leaves, or acorns get
sucked into the engine because they will get burned in the engine. Take off
the plastic tubing between the air filter and the throttle and shake it out,
make sure nothing is jamming the throttle plate.
To reduce the likelihood of future critter incursions, wrap some wire cloth
with 1/4" mesh or smaller around the air intake inlet. You can use a
plastic zip tie to hold it in place.
Air filter housings are not the only place in vehicles that mice like to
nest. Mice also like heater blower housings, and if there is grass or foam
insulation coming out of the dashboard vents, then critters may have built a
nest in the heater ductwork. Look at the plastic mesh on the cowl in front
of the windshield and make sure that it hasn't been chewed through anywhere.
If it has, use the wire cloth to mend it and close off any openings,
especially near the hood hinges.
(correct punctuation to reply)