Is it critical to change coolant at 100K?

[toyotavios_11]

150000km or 10 years whichever come first and subsequently every 50000km or 5 years whichever come first

[RMcG]

Originally Posted by tmontague

And that is also why I said you can just simply drain and re fill as you likely will not have any benefit of a flush.

If you are set on flushing it,

I value what tmontague is saying here about a flush being of doubtful value.

I am still kind of undecided whether to just simply drain and re fill or to flush. A flush will mean extra time and effort. How much extra time and effort is involved in the flush?

I talked to one mechanic at a Toyota dealership and he said they do not do a flush unless it has been a very long time since the coolant was changed, the change is long overdue and there is evidence the coolant has begun to degrade: e.g., coolant no longer "clear," but has particulate matter present in the coolant, etc.

It seems, however, that there would be some degradation of the old coolant that remains after drainage (because some old coolant remains in the system after drainage), even if you cannot see the degradation (e.g., particulate matter, etc).

QUESTION(S): Does anybody have any objective evidence a flush will be of benefit or no benefit?

Does anybody have a lot of experience with this question?

Thanks,

R.

[tmontague]

I'm doubtful there will be any objective evidence floating around.

I've been wrenching on old used cars for year - I buy them at their lowest price and put a lot of time into them so that I can be sure they are safe and comfortable for my family and last another 5 years at least. I end up with a great car fir pennies on the dollar.

One thing I've learned is what is useful and what is just wasting time and money. Coolant flush on proper oem fluid that appears fine is a waste. I have only flushed my yaris when I got it because it had green coolant in it.

I used to drop trans pans and swap out filters when I changed trans fluid. Every single time the filters were completely clear (all fine functioning trans, not blown apart). So now I just do a fluid "flush" using the trans cooler line. Saves me time and money on something that has shown no benefit.

In the end of the day it is your time and money so do what makes you sleep at night. But trust me when I say that a flush is a practice in futility in your case. This is coming from someone who is objective data driven and applies real world experience the best that I can to that. Ie: using 0w20 oil on the track amidst the cries of tradition