2010 prius 3 with 121000 miles on it, should i do the 100k maintenance?

whatever is in the maintenance manual. it's not much, but worth doing. i would do the 120k service, plus anything you skipped along the way.

 

A transaxle fluid change is the only service not in the manual that I would add.

http://www.toyota.com/t3Portal/document/omms/T-MMS-10Prius/pdf/2010_Prius_WMG_0W20_lr.pdf
(page 55 of the PDF, page 53 of the manual)

 

120,000 does include a spark plug change, as well.

(we can only show you what Toyota, recommends, ignore what the dealer recommends if it is not on that list, and not a transaxle fluid change)

 

tony, are you on vacation or something?

 

You need to do the spark plugs, engine coolant, inverter coolant, transaxle fluid change and brake fluid flush.

 

That seems like overkill. We're at 45000 km, yet to change either of those filters. Depends on air conditions I guess.

You mean pad thickness? If it's not been done, you really should disassemble a bit, pull the caliper pins, clean and relube. If DIY, be careful with the rear piston, it's cross pattern orientation is important on re-assemble. Look at the imprint on the shim for correct orientation. Turn it clockwise as needed.

Also good to disconnect the 12 prior, and pump brake pedal several times to build up pressure, after.

 

I'm curious, after 121K miles have there been any repairs or issues that would have made an extended warranty worthwhile? I'm 16K miles away from having to decide and I am leaning towards not making the purchase based on the reliability record evidenced on PriusChat.

 

Sparkys and coolant change for sure. Also, make sure you use the Toyota coolant if you do it yourself.

 

Unless you are still in warranty, there's no reason to buy the overpriced Toyota coolant. Any coolant rated for 100K miles that matches the specs will do the job (Toyota's coolant isn't special...just made for them). Also, if you do it yourself, be sure to find a way to properly clean and flush the whole system. Toyota WON'T do it unless you pay a lot more. They are content to drain and refill the system and call it done. They pulled that on my dad with his Highlander. We just disconnected one of the coolant hoses to do a "flush" after running the cleaner and to ensure all the water/cleaner was out of the system before refilling.

 

Also curious if any repairs were needed that would have made an extended warranty a good idea.

 

There is no such thing as a 'flush' where coolant is concerned. Drain and Fill.

As for the coolant itself, DO NOT buy any old '100k' mile coolant. Either buy OEM or the same spec as Toyota. I only know of one alternative, branded as Zerex and called 'Asian long life'. Around a year ago I bought 6 gallons for $66 shipped from zorotools.com

If you are interested in Chemistry details, coolants tend to group into those that are silicate or phosphate based, with or without borate, and then further sub-group based on the use of either 2-HA or sebacate. Toyota SLLC is a phosphate based borate free anti-freeze that uses sebacate.

These details matter because the manufacturer chooses metals, rings and gaskets to match the coolant. Mismatches lead to early degradations and leaks.

 

How do you propose CLEANING out any gunk that accumulates over the 100K up to the drain and fill? All systems have to deal with this issue.

More so, as I pointed out, Toyota WILL NOT do it correctly for an affordable price. The Highlander required removing plugs in the engine block to completely drain the system. The service Toyota offered was a basic "drain and fill" meaning they don't even get 100% of the old coolant out first....but they charge for 100% of the capacity your system needs.

 

Use the correct coolant and follow the recommended changes intervals to avoid the problem in the first place. From my reading, the problem you are describing is common in silicate based coolants that have been used past their recommended life, and from the very poor practice of mixing different coolant chemistries together. The latter practice is usually seen in those owners who just buy the cheapest stuff in the store because "it is all the same."

Much more so than in earlier cars, the coolant and oils are part of a package engineered to play nice and extend the life of the mechanical and electric car components. Play by the rules, meaning use fluids spec'd to Toyota recommendations and follow the maintenance schedule. Then you will not have to improvise to remove 'gunk', or deal with failing pumps and leaking radiators due to incompatible coolants.

 

So the "rules" have changed in newer engines? Even as recent as 2000, most any coolant system, even with changing coolant every 2 years, you were to "clean and flush" the system to remove buildup.

 

Correct. Some of the older systems called for a flush and fill at prescribed intervals by the OEMs.

All of the newer Toyotas and Hondas call for drain and refills. As Sage mentioned, the chemistry varies significantly on a lot of these ext life coolants. The so-called universal coolants do not have the correct chemistry for each application.

I have yet to see an Asian vehicle with "lots of gunk" in the cooling system, that required chemical flushing. As long as you drain and refill at the correct interval, you shouldn't have any issues.

The intervals take into account the amount of coolant removed. If you notice, the manual calls for the first service at 100k, and subsequent services are done every 50k. Honda and Nissan also take a similar approach.

 

I can't find any reference to "flush" in the Toyota manuals for my 2014 Four, they just say "drain and refill". And they are very adamant about using Toyota Super Long Life or equivalent coolant, with a list of "non-" ingredients, as in non-silicate, etc. They don't mention engine problems per se if you don't, only the probability of having to change the coolant more often, but I can see silicates, etc., having an adverse affect on hoses, gaskets, etc.