After successfully changing the Cabin Air Filter on a 2004 ES330, I poped the hood to change the engine air filter. Maybe this is really an obvious location for the experienced folks.. but I couldn't find it.

i searched the ES forum for help, but there was no previous discussion on it. anyone?

 

driver's side of engine compartment. Black square box with accordian type hose coming out of it. The box is large and just in front of the strut brace and behind battery.

Two 10mm bolts must be undone. There is a bracket on the back side with a philips screw. Remove the screw to release the bracket and the top part of the box will pivot up better (hint: use a magnetized stubby screwdriver so you won't lose the screw). The end of the filter box that does not have the 10mm bolts is a molded hinge in and of itself. Tilt the cover up a couple of inches and the filter can then be slid out towards the fender. Slip the new one in and then tighten the bolts. Replace the bracket and screw.

Note, the filter is marked at to top and an arrow should be on the filter indicating which edge of the filter faces the front.

good luck.

steviej

 

Airbox circled in green

 

a picture is worth a 1000 words.
Thanks mr. mcelligott, much obliged.

steviej

 

thanks guys!

 

I changed my engine air filter on the 2002 ES300 which looks similar to the above picture. I took off those two 10mm bolts that steviej talked about. I took then off one screw at the back of the air filter box. This screw held a VSV switch to the filter box using a bracket. I also disconnected the MAF sensor. There's a big rubber pipe at the top of that box which has two steel fasteners at each end to tighten the pipe. This pipe was really stiff and wouldnt let me take the box off so I loosened the screw closer to the side of the filter box. I pushed the rubber pipe back. Now I was able to lift the filter box up and take off the filter. Yeaa.
Then I took the filter to my place and vacuumed the filter from the dirty side where all the junk comes in. I used a vacuum attachment that you can use for corners and small spaces. It looked good after that. It didnt look like new but its good enough to run for another 5 years and then I'll vacuum it again. I worry about the environment so I try to re-use stuff as much as possible, plus I dont have to spend money on a new filter. That filter can deal with a lot of air flow. It will never get clogged enough for the engine to notice as long as you keep vacuuming it every few years.
A few years ago I faced this same issue of not being able to open the filter box and I caused a lot of problems and vacuum related OBD check-engine errors by being in a hurry and trying to force that box open. The VSV switch broke and I drove around with an open vacuum pipe. Moisture must have gotten into the vacuum system and one of the other vacuum valves near the fuel tank rusted from inside. Over the years I paid about $500-$600 for making this mistake (VSV replacement for both locations and diagnostic costs) and a lot of headache. Hopefully I've learned my lesson. This time I was very careful.
I also cleaned the MAF sensor with 99% alcohol and a carefully cut and folded paper napkin to make a tiny rag out of it; a small rag made of multiple layers of paper napkin. First I checked to see how thick that wire is, in case its too delicate to be cleaned by contact. The wire looked thick and sturdy enough. I sprayed/dipped the alcohol into the paper napkin rag and carefully slided it on both sides of the wire. I then doubled the rag to make it more stiff and use that to clean the top and bottom of the wire. I also cleaned that brown diode where the wires come in. I read on the internet that people had used a Qtip but thats too thick to reach in there to get to all the surfaces. I used a magnifying glass to compare the before and after and yes it looked cleaner.
I closed everything and started the car. Works good for now, no issues. I'll check the MPG over the next few months. Will be nice to get a 2MPG boost or something. That's $8/month for my driving.
I read on the internet that the wire is a main part of the sensor. Its not just a connector. The wires are heated and when air flows over, the wires cool down and their temperature changes and the current passing through them changes which can then be used in the measuring system. The MAF sensor is an open-loop thing. Together with the oxygen sensors they're able to make it a closed-loop system and have very accurate information about the air flow coming it.