Why Not to use SuperTech Coolant in your Prius

That would satisfy me, but because I do not fully understand specifications for coolants, I would still stick with the OEM.

 

Took me about 10 seconds to come to the same conclusion. Hey, I'm there getting an oil filter, maybe some ATF-WS or peanut bulbs, one stop shopping.

 

You use the best because you have a gen3 which have chronic head gasket erosion ruining engines.

Old coolant and carbon based pre-ignition are the effective maintenance based factors you have control over. Without a rebuild you can't fix the flawed pistons and rings or install a revised head gasket. Without a frankengine (block gen4 - most of the rest gen3) you can't fix cylinder cooling or block geometry. With good rings the poor egr design will flow far less hydrocarbons into the cylinders reducing pre ignition chances.

Use Toyota Concentrated coolant (on sale now at some online dealers for Black Friday -some with free shipping or in store pickup) and distilled water. Change every 30k-50k,

 

aka Toyota Long Life coolant? I'd consider that if there'd been a water flush.

New Gen 3 and Gen 4 short blocks are neck-and-neck for price:

Short block assembly for Toyota Prius ZVW30L-AHXEBK, 04.2009 - 12.2011 - Toyota North America Car and Auto Spare Parts - Genuine Online Car Parts Catalogue - Amayama

Short block assembly for Toyota Prius ZVW50L-AHXEBA, 11.2015 - 12.2018 - Toyota North America Car and Auto Spare Parts - Genuine Online Car Parts Catalogue - Amayama

(new gen 3 short blocks for sale will have the revised pistons/rings, according to TCCN youtuber)

 

Concentrate is a better deal per mixed gallon and is fine when 50k miles is the high end of coolant use by design or by choice.

Going with a new short block makes little sense on gen3s 10-15 years old with 150k or more miles when the engine needs replacement. It creates a $8k-$10k engine job when a $3.5-$5k rebuild is just as good since both options have used heads anyway.

At some point you have to factor in the value of the car after engine replacement will be less than the cost of a new short block rebuild.

In your case it's pretty academic unless you start a new job commuting 50 miles a day.

For the average consumer these days the gen3 was bought used with an unknown history. In many of these cases a fresh gen3 JDM makes more sense since many 2017-2021 JDMs are now at the JDM distributors.

Those engines have all the updates, burn no oil and could easily go another 150k miles or more. Personally inspecting those engines is the key and can result in a $1.5k-$2.5k replacement depending on labor. A plus is they come with bolt on accessories making the engine swap easier.

 

I just paid $59.28 USD for 3 gallons of toyota super long life coolant. That's including shipping and tax and comes out to $20/gallon. Why the hell would I go try to find some cheap aftermarket coolant with these prices? Only Honda and Toyota coolant, transmission fluid and brake fluid for my Civic and Prius.