50k Mile Throttle Body Maintenance

I don't remember when Toyota recommends this service, but I decided it would be convenient today since I already had the car opened up for coolant and oil exchanges. The Gen1 Prius had a reputation of dirtying the throttle plate to the point of causing problems; my Gen2 had something to clean at 100k miles but not bad. Here is the Prius Gen3 (v)agon at 50k miles:



Is that beautiful, or what ?

Surprise though, I found a pool of oil at the bottom of the throttle body when I rotated the plate to look down. Last oil change I over-filled by a good 1 - 2 cm past the 'full' mark, so the oil in the throttle body is very likely my doing. Anyway, glad I looked and it was easy enough to mop up with rags. I cleaned the MAF while I had things disassembled by putting it into a sealing plastic bag with Isopropyl Alcohol and swishing around a bit. I was sure to let the MAF part dry completely before it went back.

Compared to the Gen2 Prius, access to the throttle plate is a bit of extra work. Six screws are removed and then three plastic pieces, which combined is the entire air flow from air entrance, to throttle body. One screw hiding underneath the air filter requires an extension to reach and another is underneath the engine cover (the grey plastic thingy with the Toyota logo); the others are easy to find. There is one electric connector to disconnect, and the plastic neck that connect to the throttle body is on pretty tight and anchored by a tight spring. Yay for vise-grips! All the bolts are 10 mm, and may I say that I should have bought a battery powered impact wrench a long time ago.

A few more pictures showing the pieces out of the car:



The Wide view:



And last not but not least, a clean throttle body. The yellow blob at the bottom of the picture is the handle of a screwdriver holding the plate open.

 

No problems driving, but I found deposits on the throttle body under the plate. If left unattended I can imagine build-up over time that would interfere with the throttle plate rotation. And of course it would be a lot harder to clean when push came to shove