Coolant change interval

[Chuck1986]

I know they say to change coolant every 30k miles, however, seeing as how I only put about 5k miles/year on my car, how often should I be changing/flushing it? I know every 6 years sounds a bit long, since that's how long it takes to put 30k miles on the coolant. Also, my car is 2001 Mitsubishi Eclipse GT with 55k miles on it.

 

[Ray H]

Your owner's manual will give both time and mileage recommendations. In the case of my Sonata, Hyundai recommends 24 months/30,000 miles - whichever comes first. Since you put so few miles on your ride in a year, flush and changeout according to the time recommendation to maintain protection.

 

[robbobster]

I've always used 2 years as my guide, since I rarely meet the mileage requirements.

 

[Ken2]

Use a digital voltmeter. Put one probe in the cool coolant in the radiator neck--don't touch metal. Put the other probe on the battery negative post.

If you read 0.3 to 0.4 volts DC, it is time to change the antifreeze because the corrosion inhibitors are becoming depleted. If the voltage is higher, you're overdue. If the voltage is in the 0.1 volt range, you're golden. The voltage is generated by galvanic corrosion in the engine.


Ken

 

[NCGuy68]

Never heard of checking coolant this way but it makes perfect sense. Galvanic corrosion is the reason marine motors have sacrificial anodes on them. Same thing happens in plumbing systems where two dissimilar metals are in contact with each other.

Thanks for posting this Ken2 - However, I'am wondering how the .3-.4 VDC threshold was established?

Thanks for your reply.

 

[reyjay1]

I think it is because new coolant shows .1vdc and if it reads .3-.4v it shows that the coolant has begun to deteriorate, coupled with conventional coolant deteriorates rapidly once it starts.