Removing oil pump cover?

[maestro123]

By virtue of a miracle, I was able to get the 9 JIS screws off the oil pump cover. It took me a good 4-5 hours after I had gotten all the tools. I had to use a drill bit and a Ryobi #3 screw extractor (http://www.homedepot.com/p/Ryobi-Spiral-Screw-Extractor-Set-5-Piece-A96SE51/205469301) to get 6 of the 9 screws off. The ones that I was fortunate enough to be able to get off with just a JIS screwdriver bit (Vessel 431801 from www.phonetechsupply.com (http://www.phonetechsupply.com)) seemed to have less thread locker on them so they were able to break loose without stripping.

So now that I have the screws off, I've been trying to get the cover off, but I'm not quite sure how to do it. The cover seems to be stuck on there pretty good, and there doesn't seem to be anything to grab on for prying it off. Any tips for getting this thing off?

[maestro123]

Finally got the oil pump cover off! Ridiculously difficult. Here's some pictures.

http://i.imgur.com/Wslj8XF.jpg

http://i.imgur.com/sWVtSOM.jpg

This was not an easy job. Toyota, in their infinite wisdom, left nothing to actually grab on to take the cover off. So originally I thought I might have to be innovative and use something like a pulley puller to assist with getting it off. Turns out that the standard pulley puller for most harmonic balancers aren't even big enough to reach the screws on the side. Also, the threads are recessed into the engine block itself, so there are no threads on the cover itself, so the puller isn't able to grab anything. So scratch that idea.

Eventually, I came to the conclusion that the only way to get the cover off was to brute force it. (This actually turned out to be the correct conclusion.) I used my fingers and followed the edges of the cover to see if there was anything I could grab on. There was a tiny, tiny bit on the lower right corner that I was able to grab onto with a screwdriver and pry upwards. There wasn't much to work with, but eventually I was able to do enough prying to finally get a screwdriver wedged into the space. Incredibly, there was still a ton of pressure keeping the cover onto the engine block. It's because, in addition to the 9 screws, there's 2 rod-like stubs that are press-fitted onto the engine. Mine were seized like no other. I kept pushing the screwdriver upwards as it wedged outwards, but the rods still didn't want to come out. Eventually, in order to get the cover off, one of the areas where the rod-like stubs were gave away and cracked. Not great, but finally I was able to get the cover off.

http://i.imgur.com/cFebb09.jpg

For installation, It sucks that there is a crack in that area, but I think it'll be okay with the other stub and 9 screws holding the oil pump cover back on.

Not really sure what in the world the Previa engineers were thinking when they were working with this. I think they must have all gone on vacation and given the design of this oil pump cover area to the college interns or something, because this area, which includes the 9 screws, was unbearably difficult to work with.

In the end my oil pump o-ring gasket was actually not that bad. I still changed it out while I was there, but if there's anybody else out there thinking of doing this, I probably wouldn't consider doing it unless there's a visible leak or if the Previa has at least 200k on it. My gasket looked like it could go at least another 50k and my Previa has 162k on it. Best of luck if you attempt it. You will definitely need it!

[pdgizwiz]

I believe that what they were thinking was that the vast majority of these engines would only be taken apart by a shredder. They designed and built it to serve the first owner very well. Those of us at the bottom of the food chain have to be resourceful, and thankful that that weird O-ring that seals the cover but becomes hard and brittle by the time 20 years have gone by is still available for a couple of bucks.

[sited faith]

Thanks for the post and pics. I plan on doing this job soon. Mine's at 345k miles and started a slow leak about 20k ago. Did you use a hand impact driver with your JIS bit?

[cvtroger]

I believe that what they were thinking was that the vast majority of these engines would only be taken apart by a shredder. They designed and built it to serve the first owner very well. Those of us at the bottom of the food chain have to be resourceful, and thankful that that weird O-ring that seals the cover but becomes hard and brittle by the time 20 years have gone by is still available for a couple of bucks.

I always mention this when I talk about my Previa's rebuild process. I didn't want to just replace the head gasket and leave the rest unchecked after how many years. Even with the mentality of "if it ain't broke..." I felt that the motor was out, mind as well replace every single gasket on that motor because I didn't want drop it again any time soon.

[maestro123]

Thanks for the post and pics. I plan on doing this job soon. Mine's at 345k miles and started a slow leak about 20k ago. Did you use a hand impact driver with your JIS bit?

I did try using a Sears Craftsman hand impact driver for a few of the screws, but didn't have much luck. MIght have been using it wrong though or maybe that one wasn't as effective as other brands. I think I remember reading a few reviews that mentioned something along the line. Also, another thing that might help is heat. I noticed that all the screws had threadlocker on it, but unfortunately didn't think to use heat at the time. Doh.