To Replace Oil Pump, or Not To Replace Oil Pump . . .

First time posting -- must say, have benefitted greatly from this forum, particularly in the past three months. Thank you to all who post their experiences, expertise, and PDFs from the service manual for the 2010 Prius / 3rd gen stuff (special shout-out to Mendel Leisk whose uploads have saved me more than once in this process).

Quick up-to-speed: 2010 Prius II, at 247,750 miles (mostly long distance highway travel), second owner, purchased June 2014 at ~ 70k miles. Since then, all regular maintenance on schedule, Mobil 1 and/or oil and filters only, detail-oriented and slightly anal-retentive attention to that sort of thing. Started having weird acceleration shudders last August, very sporadic. Then started losing coolant in September. Kept a close eye, checked every day before start-up, found milkshake in early December. Been rebuilding engine since then, in my not-so-abundant free time (I'm a middle school teacher and adjunct college instructor).

At this point, I've done everything you'd imagine I'd do in this scenario: took everything down to the short block; had head off to clean, pressure test, check for warpage (no machining necessary, comments very positive on condition upon pickup); re-installed head, cam shaft assembly, timing chain cover using engine rebuild kit from Toyota; also did a whole bunch of preventative stuff for a 12-year-old, quarter-million-mile car, like all (and I do mean all) ICE coolant hoses and clamps, any rusted-out or overly rusty hardware, water pump, etc.

Now, because there seems to be an awful lot of rust in my engine bay -- not sure why or if unusual -- my engine oil dipstick tube has snapped off (thanks, Dad, LOL) leaving the end inside the port along with the o-ring. Not enough left it seems to get enough leverage to pull it out, so Dad thinks I'll need to pop the oil pan off and push it out from inside. I have time to figure this out, though, as the replacement dipstick tube is backordered for another week. Wheep whomp.

Big question: do I go ahead and change the oil pump while I'm in there? It's the last preventative measure I would probably have already decided to do if I'd already had to have taken the oil pan off anyway, which I didn't up until now. What say you all?

Corollary: if I can ask for any experienced advice or perhaps relevant manual sections, I'd be so very appreciative. Can I do the oil pump just by having the pan off? No big deal that everything is rebuilt to the point of putting the top cover back on? Definitely not into taking that damn timing chain cover off again -- my sanity barely survived the intricate assembly specs the first time.

Many thanks!!! =)

(P.S. I'm debating a post about this entire process, and random things I found to be helpful along the way, but it would likely have to be once summer comes and I have time to sit down and revisit everything. I will say, I think I figured out a great way to manage the timing chain cover reinstall without screwing up the FIPG with the engine IN the car (didn't have the luxury of a hoist).)

 

Dammit. Figured. Thought that was what I was seeing on the crappy schematics I was able to find, but wanted to be sure. Thx!

I didn't see that in what I was working with, and was told at one point by a service tech not to worry about anything to do with the oil pump, sprocket, or chain if they hadn't presented any problems. I tried my damnedest to be thorough and exact with my work, but I feel like the lack of transparency of repair information for the DIYer for something that one has paid a pretty penny to own and maintain is a crime. I would've loved to have a clearer sense of everything I should examine, measure, check, etc. during this tear-down and rebuild! I guess I'll just have to cross my fingers on this one. Thx for the information -- should've posted about this sooner, obvs.

That is very true, RE: costs. I'm around $2k in at this point, with all of the stuff I've "proactively" swapped.

 

Oh, yeah. Done-zo. =) Thx!

 

I'll be more clear -- I think that any time I spend as much as one does on a car, I should have complete and constantly updated access to the official repair and maintenance manual, laid out in a logical and user-friendly fashion, for free. =)