Trick to removing the coolant resevoir cap?

If it's like third gen it takes a bit of force: there's a tab semi-locking it. You need to push through that initial resistance.

That said, with only 18K, you may have a leak in the exhaust recovery system. It's an issue with 4th gen, Toyota's aware of it and offering free repairs. Check with dealership.

 

@ low when cold is OK if it doesn't go down farther. I'd watch it and see if it changes when at the same temperature.

 

It just unscrews like any other cap, but it has a bit of resistance until it's almost off.

Mine has almost 68k miles. Bought at about 23k. I've never added to my reservoir and it's still a hair over the full mark cold. Well, as "cold" as it gets here this time of year.

 

It took me roughly 5 years of ownership and 32K miles for engine coolant to get down to low mark. Inverter coolant did the same. Topped off both and they haven't budged since. A 2020 with 18K miles having engine coolant down to low mark seems a little premature. I'd top it up and monitor, with Toyota Super Long Life Coolant. Monitor closely cus there is a 4th gen issue, with the exhaust heat recovery system.

From my log:

====
Friday, April 03, 2015
km: 51198
* changed engine oil and filter
* lubed all hinges
* checked both air filters (blew out and reinstalled, look good)
* topped up both coolant reservoirs, both were near bottom line
====

 

if it has the same exhaust loop as other gen4's, it could be leaking.

they don't 'all' do it, but it has been an issue

 

Neither of our 2017's do that.

 

My 2017 is at the low mark when cold now after almost 5 years of service. I just picked up a jug of Valvoline Asian Red antifreeze so I can add an inch or two. I'd only use the Toyota coolant, or Prestone Asian Vehicle Red or Valvoline/NAPA Asian Vehicle Red.