Fluid maintainence and Levels

The antifreeze in the inverter is a separate loop, but just the same fluid as the engine.
"based on replacement with Genuine Toyota Super Long-Life Coolant or similar high-quality non-silicate, non-amine, non-borate ethylene-glycol coolant with long-life hybrid organic acid technology (i.e., a combination of low phosphates and organic acids)" Page 57 of http://www.toyota.com/t3Portal/document/omms-s/T-MMS-10Prius/pdf/2010_Prius_WMG_0W20_lr.pdf

The power steering is electric, not hydraulic, there is no fluid.

Brake fluid is dependent on the moisture in the air, Phoenix will need replacement less often than Miami, there are test strips to check for moisture.

About every 60,000 miles (Toyota does not specify when) you should change the ATF WS in the transaxle. It needs 3.5 quarts (buy 4) and two crush washers, about $40 at the dealer. If you have the dealer do it, expect about $125.

 

You can check all of the maintenance video on my YouTube Channel. Enjoy!

 

If there's no obvious issues with the brakes, I would leave the brake fluid reservoir level as-is. It's natural for brake fluid level to drop as brake pads wear. Typically the reservoir is design so that around the time the pads (and/or shoes) are nearing service limit, the fluid will be at the bottom mark, replace the pads/shoes, and push the pistons back to accommodate them, and the level will return to top level.

So, topping up when the pads are worn is not needed, counterproductive will likely lead to overflow come pad replacement time. That's unless there's a leak in the system, and that you don't want to solve by topping up. FWIW, the Canadian Prius maintenance now calls for fluid replacement, every 3 years or 48,000 kms (30,000 miles). @NutzAboutBolts has a video on that, pinned in the maintenance forum. I've recently done ours, left a couple of comments near the end of that thread. I would play it extra safe, use Toyota DOT 3 fluid. A couple of pints is sufficient for a fluid change.

Coolant levels near the bottom marks in the two reservoirs, I would break down and buy a gallon, top them up. The stuff lasts, sooner or later it'll get used. To play it safe, just get the stuff spec'd in the Owner's Manual.

Engine oil, the spec is 0W20. I've used nothing but Toyota 0W20 since day one, it's cheap as dirt up here. The dealership's ok with me buying bulk now, charging $4.50 (Can) per liter. Reading the oil level: the car should be level. Some people say it should sit, an hour or two, overnight, I do not know: never see much difference.

The one thing: the dipstick is bad for smearing, making it HARD to read the level. I would suggest: withdraw the dipstick, wipe it off, wait a few minutes (maybe check tire pressures), and then re-insert and read the level. By then the drawn-up oil in the dipstick tube has drained down, and you get a nice clear reading.

What else: washer fluid. I'm (once again) a Toyota chauvinist, guess I like pink fluid: the Toyota stuff is pink, rated to -40 (F or C are about the same down there??), and $3.99 for 4 liters up here. There's a nice dipstick on the cap, no need to fill right up the neck, it'll take about a gallon.

Oh yeah: transaxle fluid. Very inconvenient to check level, and pretty much pointless, if it's done right to begin with. The main thing is to CHANGE it, an early change is good, then stretch the interval. More detail, and instruction, if you're interested. Do yourself a favour if you do a change: heed the Owner's Manual, only use GENUINE TOYOTA ATF WS.

 

In my old Gen 1, I never saw either coolant level drop even a hair between changes (which I was doing every two years). My current Gen 3 (bought used last Spring) had the engine coolant a bit low when I bought it, but it has stayed right at the line so far since I changed it, so I suspect it might just have been filled a bit low by the last person to work on it.

In other words, my experience is that a healthy Prius engine just doesn't lose coolant at any noticeable rate, so if the level is lowered, that might indicate a leak beginning somewhere. But if you weren't the last person to fill it, possibly it just wasn't filled to the line exactly, so it may be sensible to just get it there first, and keep an eye on it for a while to see if it stays.

Getting the engine coolant to end up at the right level is a little interesting. There is an extra line labeled B that is above the max/full line. If you have drained and replaced the coolant, you fill to B before you go through the air bleed procedure, and at the end the level should be right down at the max/full line when the air is out. It worked out that way for me, with astonishing precision, when I changed and bled it.

If you are only topping up, not changing, then there oughtn't be air to bleed, and topping up just to the final full line should do the trick.

There's a complication checking the brake fluid level, because there is a pump that takes some of the fluid from the reservoir and stores it in a pressure vessel where you can't see it. Before checking the level in the reservoir, there's a "zero down" procedure you can request with Techstream; the car releases all the fluid from the pressure accumulator back to the reservoir so you can see the true level. Without Techstream, you can disconnect 12 volt power (so the pump can't run) and pump the brake pedal a couple dozen times to return all the fluid. The pedal should go noticeably from easy-pressing to nearly rock hard when the last of the accumulator pressure is used up. (This is back to the same way Gen 1 worked, while Gen 2 did things differently.)

If the brake pads are not new, it is normal for the true level to be below max.

After putting new pads in, it's proper to have the level at max, and it will drop slowly as the new pads wear.

As a kid, I used to just mash the caliper pistons back in when changing pads, forcing the old fluid back through the system and the level back up to max, but these days, with expensive ABS actuators, that's controversial. The concern is that any grot in the calipers and lines can be forced up into the actuator. The more cautious method is to open the caliper bleeder while mashing the piston back, so the displaced fluid just escapes ... then after all corners are done, just top the reservoir back up with fresh new fluid. You end up with a partial brake fluid change for no extra effort.

-Chap

 

It is true that Toyota has never put a fluid change in the manual. Owner experience indicates rapid discoloration when new but repeated changes show little discoloration. As such, I use 30,000 miles, 90,000 miles, and then every 90,000 as intervals.

In true 'Automatic' Transmissions, the hydraulic shift logic is a series of very small passages, making it easy to clog and fail. The old wives tail is that flushing an older transmission can force gunk into the logic. The Prius never shifts and has no hydraulic logic. (It uses Electronics to control the Motor/Generators)

This is an example of Hydraulic logic in a normal Automatic.
The Prius has no such tiny passages. So there is no risk to change the ATF at any age.

 

Toyota says nothing about transaxle fluid change, in the maintenance schedule. The procedure is explained in the Repair Manual though. If the car had a typical owner, yeah it likely never has been changed. If you do change it, and I certainly would, take some old/new fluid pics if you get a chance, and post, would be interesting.

My take, the first change is most important, ie: the fluid gets dirty fast. Subsequently changes: you begin to wonder what the point was, the drained fluid stays much cleaner. FWIW, I did a change around 15K kilometers, 40K and 65K (one year, three year, and six year). At the first change it was markedly darker, but I don't know that I'll ever bother to do another, the last change it looked like new.

 

If I "sneak up" on the car, first thing in the morning, open the front passenger door, reach across and pop the hood, the level looks like this:



If I then open and close the drivers door, a pump whirs and level drops to this:



When I recently changed the fluid, since there was a lot of opening/closing of driver's door, I opted to restore level to the second condition, post driver's door opening, which in my case was right at that middle mark. The first case dances around, sometimes it's right near the top mark, sometimes a bit lower.

Think it's good, am keeping an eye on it.

 

I shop Amazon/EBay with the best of them, but for maintenance it never hurts to check your local dealership: they have everything you need. Checking my bills, I see I paid $19.14 (Canadian, in March 2015). In Canada it comes in a 4 liter bottle (slightly more than a US gallon), and (we get all the perks) it's 55% instead of 50%.

Toyota says nothing about transaxle fluid change, so dealerships will abide by that, throw up all sorts of explanation, mainly due to a lack of experience. Again, I would say the optimum schedule would be to change the transaxle fluid early in a Prius' life, say around the 1 year mark, with any decent amount of miles on the odometer, and subsequently stretch the change.

Check out @NutzAboutBolts video in the maintenance forum, for a hands-on demonstration on how straightforward it is. In post #8 I've attached the Repair Manual instruction.

 

I changed the ATF in our 2010 Prius at 140k miles about 2 months ago (now have 144k and going strong). It came out dark black when it should be red. Should I have done it earlier? Debatable (which is what the bread and butter of any forum). If I did it again, would I have done it sooner? Probably. Does a difference in color mean the fluid has degraded? Not sure (I was a bad engineer and just dumped it rather than send it off for testing).

If I were you and considering some jobs to do before winter sets in, doing all 3 fluids is a good idea and is not time consuming (if you have your father help all 3 jobs can be accomplished in about 3-4 hours stopping for breaks in between). That's what it took when me and my old man did it in September. The drain plugs are hex heads, and getting a set at harbor freight is cheap and makes a nice addition to the work bench. They will be on there good, so be ready. The trick is getting the car level for the ATF drain and fill.

Good luck and keep us posted.

 

Yeah, the sockets you need, for both the fill and drain bolts, look like these:



You need the 10 mm size. Again, torque for both is 29 ft/lb. Breaking them loose is a LOT easier with a long handled ratchet wrench, say 18"ish. And kosher would be to use a fresh washer and torque when reinstalling. For sure remove the fill bolt first, just in case it's a fight. You don't want to remove the drain bolt, then find the fill bolt is stuck.

(One thing I miss about Honda: their transmission drain bolts (similarly) are socket cap screw, but have a 3/8" square recess, that you can just fit any ratchet wrench directly in, without special socket.)