I am cleaning the parts on my 95 4runner 3.0l 3vze (while the guy rebuilds my alternator for the SECOND TIME... In 2 years). Anyway, I take apart air-box, and find a small hole at the bottom. It's really small. I can not tell if it is a intentional breather/drain hole, or a manufacturing defect. It is mostly a perfect circle with a flat. This is definitely NOT a stress fracture, or eroded hole.

Before I put it all back together, should I fill it with some super-glue & baking soda, or just leave that?


Small at bottom in airbox

Small at bottom in airbox

 

That hole could have been drilled nicer...

Depends?
If you have a snorkel, I wouldn't want to see that hole.
If for some reason there is water build up in the air box, then a hole would make sense. (But how would the water get there?)

Questions over questions. Close it off.

 

There is a plastic pipe that goes into the airbox with no seal that is neither air or water tight. If there WAS water around this it would be sucked up into the air box. Even more curious is the fact that it is right on the part of the mold where the plastic is set and extra flashing would have been cut or ground away.

Even still, water can trap in the waffle-iron matrix of cavities and then only possibly drain out of this small hole only in the event of an extreme overflow when the engine is off and not sucking water into and through the air filter.

 

Hot glue or duct tape.

 

After 2 years i don't think I'd worry about it, but if you'd sleep better put a dab of black silicone over it...

 

im with 874runner, black silicon. superglue and baking soda sounds like too much work.

 

There's one on my truck's. Probably drain for any condensation or minimal water intrusion.
However, IF you expect the airbox to be submerged in water, I agree that that hole should be sealed and ideally a snorkel used.

 

I am pretty sure the hole is supposed to be there to drain excess moisture from the air box.

For stock applications, I would just leave it alone. It is on the "dirty" side of the air cleaner assembly, so any air that does come through still has to make its way through the air filter.

If you are worried that water will make its way into the air cleaner and flood out the engine through that little hole, you will have much bigger things to worry about, like all of the water coming through the first intake tube.

If that is the case, then installing a snorkel and sealing the entire intake from the snorkel to the engine would be your best bet.

There is no need to plug up that hole unless you have a specific reason to.