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Mice & Air Filter

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.

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.

Regards,

Fred

Reply to
Cornerman
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It takes very little air to keep an engine running at low revs. Checkout the size of your idle control valve (about 1/4 inch square on mine) and I can tell you that on mine that can hold my revs at 2Krpm happily up a small incline.

J
Reply to
Coyoteboy

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.

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.

Reply to
Ray O

Is Saran Wrap thick? Because ive nearly ripped my fingers off trying to stall my engine blocking the intake with my hand at idle - i cant imagine plastic wrap lasting long?

Reply to
Coyoteboy

Good point! Saran Wrap is pretty thin so only wrap the OUTSIDE part of the air filter, not the inside!

Reply to
Ray O

Sounds like the filter did its job well and you might be in for a pleasant surprise of improved gas mileage. I bet its also safe to assume if there were any other problems under the hood you would have already found them.

Now comes the really scary part were you have to actually let your daughter have the keys. :)

GL Dan

Reply to
Danny G.

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