Why does radiator coolant need to be replaced?

Status
Not open for further replies.
Joined
Nov 4, 2016
Messages
476
Location
MN, CA
My car passed 60,000 which means I need to flush the coolant.
But why?
It still looks nice & green. It feels like I should be able to run to 120,000 since the radiator still continues to keep the engine from overheating. What exactly happens to coolant that it requires replacement after 60000 miles of usage?
 
Last edited by a moderator:
The corrosion inhibitors give up. What mechanism that is, I dunno (what wears or gives out). But due to the dissimilar metals in the system, once those inhibitors go, so does precious metal.
 
It lubricates the bearings in the water pump. Those "lubricants" wear out over time. The PH level, or acidity, also changes over time, so you want to get the old stuff out and replace so it doesn't corrode.
 
It doesn't in any of my cars, and I've yet to see one where it does. A water-glycol mix is not a very good lubricant, every time it has migrated past the seal into the bearings it has caused them to fail in short order.

Originally Posted By: bubbatime
It lubricates the bearings in the water pump. Those "lubricants" wear out over time. The PH level, or acidity, also changes over time, so you want to get the old stuff out and replace so it doesn't corrode.
 
Originally Posted By: bubbatime
It lubricates the bearings in the water pump. Those "lubricants" wear out over time. The PH level, or acidity, also changes over time, so you want to get the old stuff out and replace so it doesn't corrode.


With the advent of mechanical seals in water pumps I thought that "lubricating" seals/bearings was no longer applicable.
 
Originally Posted By: veryHeavy
My car passed 60,000 which means I need to flush the coolant.
But why?
It still looks nice & green. It feels like I should be able to run to 120,000 since the radiator still continues to keep the engine from overheating. What exactly happens to coolant that it requires replacement after 60000 miles of usage?
Anyone who waits until the engine is overheating to change coolant is crazy. You you wait until your tires blow out before you change them/
 
Originally Posted By: veryHeavy
My car passed 60,000 which means I need to flush the coolant.
But why?
It still looks nice & green. It feels like I should be able to run to 120,000 since the radiator still continues to keep the engine from overheating. What exactly happens to coolant that it requires replacement after 60000 miles of usage?


Drain and refill. No need for a flush if things look good. The additives wear out. Drain and refill is cheap compared to parts replacement.

Use the proper coolant and distilled water.
 
Last edited:
The add pack in coolant(mostly corrosion inhibitors) breaks down after a while - more so with conventional green coolant than the OAT(Dex-Cool) and hOAT(Japanese coolants with phosphates, silicated hOAT like G-05/G-40/G-48) coolants used by the OEMs these days.

In rare cases does glycol break down to glycolate - and game over if that does.
 
Last edited:
Originally Posted By: bubbatime
It lubricates the bearings in the water pump. Those "lubricants" wear out over time. The PH level, or acidity, also changes over time, so you want to get the old stuff out and replace so it doesn't corrode.
any pump made after 193somthething has sealed bearings.. it's the anti corrosion and pH that gets bad.
 
Last edited:
Originally Posted By: bubbatime
It lubricates the bearings in the water pump. Those "lubricants" wear out over time.


You shouldn't repeat everything you hear at Jiffy Lube.
 
Water pump or bearing lubrication is nonsense and it has been nonsense for a long, long time in automotive world.

As any automotive fluid, coolant oxidizes, depletes its additives, changes its optimal PH level and simply put, deteriorates through chemical and electrolytic reactions.
 
...Any lubricating needed is just the seal itself. Water pumps have mechanical seal and the water keeps them cool. Anyone that thinks water ever lubricates bearings should think twice
 
Originally Posted By: Kawiguy454
...Any lubricating needed is just the seal itself. Water pumps have mechanical seal and the water keeps them cool. Anyone that thinks water ever lubricates bearings should think twice

Definitely. It's just the seal, which is why I don't like to spin pumps dry, even briefly. The seals are spring loaded too, so it's not hard to imagine how being dry or bathed in precipitated-silicate and insoluble-contaminated coolant can wear out a rubber seal that's spring loaded against a housing. The glycol does indeed provide some lubrication to the seal, but conversely the glycol itself never "wears out".
 
Instead of second guessing the recommendation to drain and fill your coolant, ask yourself this:

Is it worth the extra (approximately) $20 I would spend on the coolant (and pennies for the water) to safeguard my engine from potential failure or damage resulting from NOT changing out the coolant at the recommended interval?


In my mind, spending $20 or so for the coolant and an hour or two to drain and fill in my driveway - ONCE per 60,000 miles - is WELL worth it.
 
I recently topped-off the radiator with fresh coolant. Hopefully that will hold me until my 70,000 mile oil change. The dealer charges $150 for radiator flush.
 
Originally Posted By: veryHeavy
My car passed 60,000 which means I need to flush the coolant.


How many years?

Anyway, just be gland that you really only have to do this once, since once after this, the coolant will get changed out mostly every time a cooling system component gets replaced.
 
Besides not knowing how the pH scale is arranged, that is not how it works. First off, any solution near neutral has almost no H+ concentration and the pH can be altered much easier than a solution that is farther away from neutral (on a logarithmic scale). Second, coolants are buffered and up to the limits of the buffers it will work to maintain a constant pH.

Whoever wrote that article doesn't have even a slight understanding of chemistry. I wouldn't put any stock in anything else they write either.

Originally Posted By: veryHeavy
Originally Posted By: JMJNet
Check out this link:
https://www.cartechbooks.com/techtips/antifreeze
"Here’s the pitch: water has a pH of 7.0 and antifreeze has a pH of 10.5, so a 50-50 mix has a pH of 8.75, and that’s too acidic to protect the cooling system"

8.7 is not acidic.
It is a base.
 
Status
Not open for further replies.
Back
Top