I had the opportunity to chat with a seasonal Mitsubishi master technician yesterday. I learned that while Mitsubishi's Super Long Life Coolant Premium has a minimum coolant change interval of 60,000 miles (95,000 km), changing the Evo X's coolant every 75,000 miles (120,000 km) is already a prudent interval.

What interval would you change your Evo X's coolant, given that the car is mainly street driven?





^ Sneak peek of an actual coolant bottle sitting at the Mitsubishi dealer's workshop.

 

Owners manual should tell you. Most vehicles are 5 or 6yrs or 100k miles.

 

According to the manual it says every 30k. I just did my first one at 38k just to be sure. Cant hurt the coolant is cheap enough

 

Maybe I should send a coolant sample to a lab for analysis next time. Many people change their coolants at much shorter intervals. If I were to have faith in Mitsubishi's coolant technology, the coolant should remain good and non-corrosive at very large intervals like 5~6 years as you said.

 

Biggest thing with coolant is to check to see if it's carrying voltage. Using a voltmeter, stick the positive probe in the coolant in the radiator, and ground the negative probe. If it has voltage, it typically mean it's turning acidic.

There are also test strips you can buy for coolant to check the Ph.

 

Thanks for letting me know of this!! First time hearing this and I've also found a video explaining the voltage method.

https://www.youtube.com/watch?v=mHTM3dvpD1M&t=336

 

I used the above method and sampled some coolant in my reservoir. It looks fantastic for its age (60k miles i.e. 100k km). I guess I will wait a bit and change the coolant when I upgrade the hoses to Mishimoto silicone ones: