Time-saving Tip When Changing Engine Air Filter

RX in NC · November 3, 2007

The engine air filter in our 2004 RX330 AWD is accessed by using a socket wrench extension to unscrew two 10mm bolts that, once completely loosened, allow you to then swing open the top of the air filter housing on its two plastic hinges so you can then remove the old air filter and install the new one. Be aware that the two small square metal nut bases that accept these bolts (and therefore tighten the top part of the housing onto the lower part of the housing to hold the new filter in place) can and will easily pop out of the plastic brackets where they are snapped into place on the bottom side of the lower housing. If your luck is anything like mine, the metal nut bases then rattle down into the engine compartment and disappear from sight. It took me nearly an hour this afternoon to locate and retrieve them using a magnetic extension wand made especially for this purpose. What a pain in the !Removed!....

To prevent these small square metal nut bases from falling down into your engine compartment when you loosen the two 10mm bolts that hold the air filter housing together, simply spread an old hand towel out just underneath the entire length of the air filter housing before you loosen the two bolts. Then if the metal nut bases pop out when you loosen the two bolts, they will fall into the towel and you can easily retrieve them by removing the towel slowly and carefully....

I learned this trick the hard way today, not knowing that the metal nut bases would pop out once the bolts are loosened. Most air filter housings today use built-in clamps to open and close, but unfortunately not this RX330. It's a poor design and you really have to be careful every time you go to change your air filter. I don't know if this design applies to all RX330s, but I advise you to spread an old hand towel underneath your air filter housing just in case....

And finally, once you change your air filter and retighten the bolts to close up your housing again, be sure to check that all vacuum hoses running to and near the housing are attached to their fittings as they should be. It is very easy to pull these small hoses from their fittings in the process of opening the housing to change the filter....

lenore · November 4, 2007

Maybe you could take the nuts out and put bolts in with wing nuts facing upward. I dont know, because I dont have a rX330 but maybe that could be done.

RX in NC · November 4, 2007

I thought about converting to upward-facing wingnuts but didn't have any on hand that were small enough to fit that tight area. And the bolt behind the housing assembly would be very difficult to reach if you converted it to a wingnut. I change the air filter only every 30,000 miles so as long as I remember to spread the hand towel underneath the housing in the future, I shouldn't have to deal with finding a disappearing nut base again....

2004_330er · November 6, 2007

Thanks for the tip. Wish I could get such type of advice about removing the headliner to replace :chairshot: the antenna amplifier (that was broken off at the base when I bought my 330--irritating because they should have caught it and I didn't know any better and now am stuck with a hard, not cheap repair.)

GDixon · November 6, 2007

Thanks for helping us all out in a situation where frustration reins.

How would it work to put a piece of masking take under the nut to temporarily hold the nut in place? It would be removed afterwards or it would be dried out and gone by the next time the filter is changed.

A little bit of hot glue to hold in the nut might work as well. The engine compartment heat should not be enough to remelt it.

Wing nuts would tend to come loose with the vibration in the engine area would be my thought on that fix.