Antifreeze question

In June 2007, I replaced the antifreeze in my daughter’s car with 5 year/150,000 mile antifreeze. Its been 5 years, but she’s only put 40,000 miles on the car. Her mechanic (no longer me, she lives in another city) told her today that the antifreeze is still pink and therefore still good. Any thoughts?

I’d change it out. It’s cheap insurance. Rust inhibitors become depleted.

5 yr/50,000 miles means “whichever comes first”.

You can’t really go by the color of the antifreeze. Of course, it’s far better that it’s close to the original color than to appear sludgy brown.

You probably can safely get more time out of the current coolant. Some folks faithfully replace their antifreeze every three years and those who urge you to do so will get no argument from me. Of course, most such guys treat it as a very cheap driveway DIY service rather than a costly shop job.

Do you two ever get together? Show up with a fresh gallon of antifreeze and do a drain-and-refill yourself. You know it’s simple enough.

The antifreeze is still pink because it’s still doing its job.
At this point a drain and fill will replenish the additives, no need to flush.
On a car driven daily I would change the thermostat and radiator cap every 5 years too.
I changed the coolant in my car at 5 years and 24,000 miles.

Yep, drain and fill using the exact same type of antifreeze. If you change type, then you’ll need to flush first.

When you stick with one type of antifreeze, and you keep up with maintenance, you can just drain and refill. When you neglect your vehicle, and wait until the antifreeze changes colors before you change it, you should flush the system before you refill it, adding to the cost and hassle. I’d drain and refill the antifreeze, sticking with the pink stuff.

Antifreeze really does not change color. The amount of dissolved stuff(metal) in the liquid is not enough to really make a color change. But it does affect the solution as to corrosion protection. The manufacturers could make a color change indicate a coolant that needs a change but then you would likely have to pay dealership prices.

If she plans to keep the car indefinitely, change it as it does make a long term difference. If it will be traded in the next few years , there is no short term harm by not. Personally, I would do the maintenance as I always have, by the book right up till the time I trade it or sold it. You can then include your service as an included factor in valuing the car if you sell it privately. Honestly, a dealer come trade in time will not be impressed nor will he care as long as it “looks” normal.

Antifreeze does change color, but by that time, the engine is being damaged. If caught early, you might save it.

As antifreeze nears the end of its useful life, it starts turning cloudy. This is when the additives are used up. Really, it is best to change the coolant before getting to this point, that way all you need to do is a simple drain and fill. Go past this point and it gets more complicated and expensive.

We could tell you a lot of things, but let the manual be your guide.

5/50 means whichever comes first.

Good color means that the corrosion inhibitors have not completely failed yet, but the idea is to replace the coolant before it starts to eat your engine.

5/50 antifreeze is organic acid antifreeze. That stuff has been discussed on this forum at length, and the general consensus is that most of us have had really bad experience with it. I would replace it sooner than later, and I would use conventional ethylene glycol coolant.