CAT ELC color after use

[Crmsntide27]

So I've been running CAT ELC coolant for about 5 or so months now. Yesterday I drained my coolant because I wanted to do the 58v FICM mod and I noticed that the coolant was extra dark. I took some of the coolant i drained and compared it to regular coolant. Is this normal for coolant to darken after use? It cant be oil otherwise it would be separated. I'm running a coolant filter as well and I let the used coolant sit for several hours and there was not any sand particles whatsoever. Any thoughts?

New Coolant:


Used Coolant:

[NYC F-350]

Mods done to your truck? Running gauges? Whats you EOT/ECT delta?
Possible soot from a leaking EGR cooler?

[pizza pig]

he's deleted

[dhanna6powerstroke]

All I can think is that when the flush was done, it still had a little junk in it. I've never seen it that color.

[Crmsntide27]

Originally Posted by NYC F-350

Mods done to your truck? Running gauges? Whats you EOT/ECT delta?
Possible soot from a leaking EGR cooler?

Mod's in right hand corner of sig. Yes running gauges and I'm deleted. Last I checked my EOT and ECT look good which was about 3 weeks ago.

[Crmsntide27]

Originally Posted by dhanna6powerstroke

All I can think is that when the flush was done, it still had a little junk in it. I've never seen it that color.

Maybe. I used VC-9 when I flushed it and used distilled water until it came out clear. I forgot to mention though the coolant (used) smells sort of like air being let out of a tire. Whatever that means

[dhanna6powerstroke]

Originally Posted by Crmsntide27

Maybe. I used VC-9 when I flushed it and used distilled water until it came out clear. I forgot to mention though the coolant (used) smells sort of like air being let out of a tire. Whatever that means

The "stale" air smell. Could have been something stuck in the system that broke loose after a while. Hard to tell.

[NYC F-350]

Sorry, I got tired of having to scroll down past full page signatures, so I shut them all off. Made it so much easier for me to read everything.

If your cooling system was cleaned/flushed previous to adding the ELC, then I haven't a clue.

[Crmsntide27]

Another thing I forgot to mention that could possibly have something to do with it is my a/c system. Its been pretty good as of lately but for a while my ac would go in and out. In idle if I had it on full blast it would blow hot air but once I drove it would get cooler. There was also this faint screaming sound that i could hear under load and I tracked it down to one of the coolant lines connected to the degas bottle. I decided to reinforce all my coolant lines with plumber clamps since they had been taken off so many times. Since then my ac works alot better. I was thinking maybe if the cooling system was losing pressure or not building enough pressure that could have had an effect on it. Just thought I'd throw that out there. It could be nothing.

[Ironmover]

Your last post wasn't very clear but just to clarify the A/C and engine coolant are two completely different systems completely un related and do not come in contact with one another.