Compatibility of "Universal" Coolant / P0128 code

Hey everyone,

I've got a 2018 Tacoma with approximately 85,000 miles. About a month ago, I had a P0128 code which is "coolant temperature below thermostat threshold". I cleared the code and it returned about 900 miles later.

I'm also noticing (based on data from the Torque App) that the engine takes a long time to reach 168F. When cruising on the freeway, the coolant temperature drops to 161F and even after driving for a considerable amount of time, the highest engine temperature I noted is 171F. Based on the symptoms, I'm in need of a new thermostat.

The shop I'm taking the truck to will be replacing the thermostat with an OEM Toyota part. However, for them to offer any parts warranty, they require the cooling system to be flushed. The shop will only flush with a universal coolant (I think the brand is Global Antifreeze).

Is there any concern with flushing the system with universal coolant?

The shop can refill / top off with Toyota red coolant - but it won't be flushed, and there will be no parts warranty on the thermostat.

Would it be best to forgo the warranty on the new thermostat and refill with Toyota coolant?

 

my preference is to maintain the toyota red coolant. but given the age, i would also agree that a flush would be a good idea.

having to pick between a warranty and a flush, i don't like either option. i'd really consider looking at different shops, or consider doing it myself...

 

If they are using an OEM thermostat, I wouldn't care about the warranty.
I'd care more about not mixing the coolant. And I prefer OEM coolant. Toyota SLLC

 

As long as it is pink SB O.K. if you are concerned bring your own name brand fluid from the parts store.

 

Any of the asian coolant labels (pink) from Valvoline, Napa, Peak will work. Oem coolant doesn't cost very much. I've always used oem, just drain and fill.

Flushing the system is up to you. As long as the coolant meets oem spec for Toyota you should be fine.

 

I’ve been running UC for the last 5 years with no heating or cooling issues. It acts just the same as OEM. At 15 years old and nearly 200K miles I’m on my original hoses and water pump. I had an issue with a clogged heater core while using OEM. After unplugging the core I took it to a local shop that evacuated all the coolant and replaced it will UC. My thermostat failed years ago with OEM. So did my radiator cap. Nothing has failed with UC. I have a gallon of OEM and the pH of the UC and OEM is nearly neutral.

 

If you can change the T-stat yourself (get an OEM one) Toyota made draining the coolant very easy, get 2 gallons of coolant.
I prefer to use the factory coolant, the dealer sells it ready to use at a reasonable price.

Get some 5/16" ID hose, it fits the radiator drain too. If you leave the radiator cap on when you drain the radiator (before draining the block) it will siphon the fluid out of the recovery bottle too.



Remove the passenger wheel, pop the top plastic clip out and gently fold the splash shield down.



And find this handy block drain.



A long extension and a 10MM socket.



The coolant won't gush out, just get it draining and go do something else for a while.
Fill it up nice and slow, keep squeezing the top radiator hose to work the air out.

 

Thanks for the advice everyone.

I'm not having a shop diagnose the issue, but based on the symptoms, is a thermostat the most probable issue?