Question on coolant after flush

Did my first flush today. Truck is at 127k and there's no history of any coolant being replaced (bought it at 120k). After flushing and adding the Super Long coolant the old coolant didn't look to bad but when burping the air out of the new coolant, I got some orange/yellow foam bubbling up with the air. Any perspective on this?

Pictures of the coolant and the foam for reference (small bottle just for the picture, I drained way more than just that).

 

I have NO idea here…
Rust maybe??? Unlikely though.. never seen that before

 

Oil?

 

What do you mean by “flush“? Did you put any cooling system cleaner into the radiator?

The color of the coolant does not look particularly good; it should be a nice pink. So I think you are probably correct, regarding not having been changed before.

 

I'm hoping just rust. The coolant looked good from the radiator and the block - no milky coloring - only happened once I had the truck on and burping air.

 

No, didn't realize that was a step. I followed another guide here for draining both sides of the block and the radiator and then refilling.

 

I should also preface that temps are still good. Before doing the service I was at about 187-189 degrees when warmed up and after the service I'm still between 187-189.

 

It’s not recommended, but such products are sold, and I thought it was best to make sure that wasn’t a factor here.

As it so happens, I did the same operation yesterday. I’ve been on a slow path to getting a full coolant exchange done, which takes three or four times doing the same thing since we can’t get all of the coolant out of the cooling system. I get out about 6 quarts or a little more at a time.

 

It's not necessarily a step, but what you did wasn't a flush. Just a drain and fill. As for the yellow foam it's most likely due to cold temps outside allowing moisture in. Or oil

 

Sweet. That was kind of my mindset too. Original owner took good care of the truck but not much service history of what fluids were done so I'm slowing doing everything for peace of mind.

 

Gotcha. Thanks for the clarification! I'll keep an eye out for anything out of the ordinary in the future.

 

Maybe the coolant was starting to break down?
Funny but informative video:
https://youtu.be/HPVckPH6o-w?si=yUcLyMcVVe8x2CgZ