trogdor113

I looked but didn't find any information about how to change the coolant on a 600h. It's really not hard, but there a few things that are nice to know ahead of time. As most hybrid owners should know, the LS600h has separate coolant loops for the ICE and the hybrid inverter, but they use the same Toyota Super Long-Life Coolant (SLLC). For that reason, and because most of the work is in the same general area, I think it makes the most sense to do both at the same time.

Tools and materials:

• Gasket ring for the inverter coolant loop drain plug (90430-A0003)
  • This is a very common part and can also be found easily and cheaply at a Toyota dealer
• Approximately 3 gallons of Toyota SLLC or equivalent
  • I used Zerex Asian Formula Red; the important thing is a coolant that's silicate-free and features hybrid organic acids (HOAT)
• A bucket to collect coolant
• A 6mm hex driver
• A 10mm hex driver
• A 10mm socket
• A ratchet, extension (10+ inches / 25+ cm), and U-joint for the 10mm socket
• A torque wrench for the 10mm socket setup
• A smallish flat-head screwdriver for removing trim clips
• A bright headlamp or other easily-positioned light source
• Access to Techstream or an aftermarket dealer-level scan tool
  • This is pretty much a hard requirement because you need to be able to actuate a few things in the process

With materials and tools in hand, here's what to do:

• Pop the hood
• Remove the large silver engine cover with "Lexus Hybrid Drive" on it. There are four press fittings at the rear; lift at the rear to disengage these, then slide the whole cover toward you to remove. There are two clips at the front that will be damaged if too much vertical force is applied, so be sure to lift at the rear and then slide
• Remove the clips from the black cover piece forward of the engine cover you just removed. I'm pretty sure my car is missing some, but I think there should be 5?
• The start of the air intake ducting is now exposed. Remove the 10mm bolts securing it at the front, then pop it off both filter boxes. The duct just presses onto the boxes and is secured by small ears on the box:
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• The combustion engine's coolant reservoir is now exposed at the front of the engine bay; wipe it and its cap off, remove the cap, and set it loosely back in place so nothing falls in
• Locate the upper radiator hose at the right side of the engine bay. Use the 6mm hex to remove the vent plug, and set it loosely back in place
• Remove the left and right engine bay covers after removing all of their clips
• Jack the car up and support it with stands at the designated points behind the front wheels. If you're a lucky SOB with a lift, drive on and raise the car
• Remove the forward-most engine cover under the car (lots of 10mm screws and clips)
• Just behind the bumper and above the subframe you'll see a pale yellow, plastic winged plug; there's a hole in the subframe for the spigot below it. Place your bucket under the drain, then open by twisting counter-clockwise.
• While that drains you may as well remove the rest of the panels. Remove the second from the front next (the panel below the oil sump):
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• Remove the third cover, the one below the transmission:
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• The radiator will probably be just dribbling at this point, but if not wait until there are single drops. Close the drain by finger-tightening the spigot clockwise. Remember that this is plastic that repeatedly heats and cools and is therefore relatively brittle.
• Move the bucket under the left-side block drain. It's basically impossible to describe its location in words, but here are some pictures that zero in on it. The forward corrugated boot is the left outer tie rod end and the rear boot is the axle:
  • NOTE - I totally snapped off the head of the drain bolt. The drain is relatively rear-set and there's not a great angle, even with the U-joint. If I was doing this on someone else's car, I would skip this side, especially now that I've seen how much can drain from just the right-side block drain.
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trogdor113

• Move to the right-side block drain. This one is even harder to spot, but I found it much easier to drain (ie I didn't break the bolt). Use these pics to locate it:
  • The boot here is the right-side driveshaft
  • You don't want to open it much, just enough to allow a constant stream. Walk away and let it drain for a good five minutes; a little patience goes a long way here
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• Snug up the block drain, remembering that this is a small bolt that's relatively corroded. There's technically a torque value in the manual, but it's so low (13 Nm) and the angle so great that it's essentially meaningless.
• Under the hood, locate the inverter coolant reservoir. It's located at the rear on the right side of the car and is very helpfully labelled. Wipe it down, then remove the cap and loosely replace to allow for faster draining:
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• Move under the car to the transmission. Locate the small cover plate at the front end:
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• Remove the plug with the 10mm hex driver. I know this feels like you're going to drain transmission fluid, but remember that MG1 is the front motor in the transmission and charges the high-voltage battery with rotational energy from the engine; it's part of the coolant loop. Here's proof that it's indeed coolant:
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• Once it's drained, remove the old gasket ring from the plug, replace it with the new one, and re-insert the plug. Tighten to 39 Nm
• Double check that you've closed and tightened:
  • Radiator drain spigot
  • Engine block drains, both left and right
  • Inverter coolant loop drain
• Re-install all three panels with their clips and screws, then lower the car. You're done with the really messy parts and crawling around.

trogdor113

Have your coolant handy and get Techstream or your equivalent tool plugged in and connected. Here's how to refill the inverter coolant loop and the engine coolant loop:

• There are two vents in the inverter loop to prevent air bubbles. Remove the clip from each one, then pop its rubber nub off. One is on the left of the engine bay behind the inverter coolant reservoir, and the other is on the right side next to that side's air filter box:
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• Slowly add coolant to the inverter loop reservoir until it reaches the full level. There are markings on the tank that can be read from the front:
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• Replace the bleed caps with their clips
• Leaving the reservoir cap off, pull up the hybrid control module in Techstream or your tool, load the active tests, and start the inverter coolant loop's electric pump. You'll see the coolant level drop and hear a very sad whine
• Let the pump run for five minutes. While it's running, add coolant to restore the level to the full line. You'll likely add some, then the level will drop, then add some more, etc.
• Stop the pump and wait one minute to allow the level in the reservoir to stabilize
• Continue cycles of adding coolant while the pump runs for ONE minute, then waiting one minute with the pump off. Repeat until the level is stable.
  • You'll know when the circuit is full as the pump will be much quieter and there will not be bubbles in the reservoir
• Replace the inverter loop's reservoir cap; you're done with the inverter coolant.
• At the front of the engine bay, add coolant to the engine's reservoir to the full line. Get friendly with the radiator hoses and massage them to get coolant throughout the circuit. Continue to add coolant and massage until the level is stable at the full line.
• Replace the vent plug with the 6mm hex driver. It's going into a plastic neck and the torque value is very low (1.5 Nm) so tighten just until snug
• In Techstream, pull up the hybrid control module again, then Utilities, then the Maintenance Mode utility. You want to activate the emissions inspection and 4WD mode; this will force the engine to run while the car is on. The utility will only work under very specific conditions, so you'll likely need to turn the car off, then press the start button twice with your foot off the brake pedal to bring it to ON but not READY
• When the utility prompts you to, start the engine by pressing the brake pedal and then the start button. Turn off the climate control if it's on
• Allow the engine to idle for ten minutes. While it does, monitor the coolant level in the reservoir and continue adding to keep it at the full level.
• At the end of ten minutes, leave the engine running and fill the reservoir above the full level to the base of the filler neck
• Still leaving the engine running, replace the reservoir cap and hold the engine at 1500 to 2000 RPM for five minutes. Confirm that the thermostat has opened by feeling the upper radiator hose
• You can now shut the engine off and unplug your laptop or other tool. Leave the hood up and allow the engine to cool to ambient temperature
• Add coolant to the reservoir to restore it to the full level again
• In my case, at least, when I activated the climate control again while test driving, the coolant level dropped again and there was no heat. The FSM specifically states not to run it during the above procedure, YMMV. You'll likely want to drive it a couple of times and continue to fill after each one
• Replace the various cover pieces in the engine bay

That's it! Doing all of the above took me a few hours, but a good chunk of that was spent hunting for the engine block drains, and waiting on coolant to drain from the various orifices. This isn't a hard job by any means, but you do want to be sure to be thorough to avoid problems with air in the coolant loops. I figure I emptied about 2 1/2 gallons from both coolant circuits (5 gallon bucket):

Gerf

You must know your cv boot is oozing grease and the lower control arm bushing doesn't look that great right?

trogdor113

lol, post pics on an automotive forum, and everyone will pick up on everything but the thing you're trying to show

Yes, there is a hearty helping of CV joint grease on the frame there. I looked the boot over though and don't see any damage; I would guess that the axle was replaced previously and the mess wasn't cleaned up. I would agree that the bushing isn't in the best shape of its life, but it's not showing any symptoms at the moment. When there are thumps and bumps I'll know where to look

Anfanger

Thank you for the contribution! But I would use Toyota coolant instead.

trogdor113

Yeah, there's always going to be a debate over which fluid or oil or filter to use. I definitely don't recommend going for any old antifreeze. I like the Zerex because they don't produce a "multi-vehicle coolant" that's "compatible with all makes and models". Instead, they have specific formulations for different manufacturers. I've used their products in my relatively picky BMWs and VWs without issue. Zerex Asian Blue went into our Honda Odyssey when I changed the timing belt and served well until we finally sold it 75k miles later.

The key thing for Honda and Toyota is to avoid silicates and ensure the presence of HOAT. The silicates in some coolant formulas is supposedly damaging to the pump seals used in Asian makes. That being said, you obviously can't go wrong with the manufacturer's product, and for some people the difference in cost is worth it.

lwphat66

Nice job and an excellent detailed write-up to boot! While OEM is the way to go in certain areas, there are also very good OEM equivalents or better available. As you mentioned in your first post, HOAT is the coolant recommended for our cars. I do not believe it's "silicate-free", but rather it's phosphate-based and not silicate-based (but technically I'm not a chemist either ). Regardless, we have been using the following in our family's 6 Lexus/Toyota vehicles for several years now without any issues whatsoever. OEM Extended Life PINK Antifreeze/Coolant - Recochem

Again, great work with your contributions and glad to have you as a part of our LS family.

trogdor113

I'm an IT engineer by day and ended my pre-med aspirations in college when I took CHEM 106, so I'm rusty on my chemistry as well. You got me curious enough to look it up in the service manual though, and it states:

I think we're both right and saying the same thing, but I neglected to call out the presence of phosphates that you pointed out. I've also read the RECOCHEM is a good product and compatible, I've just never seen it locally. I can easily get Zerex and Pentosin fluids at the nearby parts stores, so I often go with the appropriate match from those brands.