Small black dots in coolant

Status
Not open for further replies.
Joined
Aug 14, 2015
Messages
2,430
Location
CA, USA
Yesterday I drained the coolant from my Civic and put in some new stuff. This was only my second drain & fill, so I'm not sure if this is anything to worry about or not. I noticed when I was waiting for bubbles to come to the top of the radiator cap hole, I would occasionally see small black bits at the surface. I got a paper towel and swabbed a few of them. One of them is the black dot here in this pic. The pic is magnified about 2x.

The coolant history of this vehicle is spotty. I have no idea about its maintenance before 80K, when I bought it. I don't think I touched the coolant until about 150K, when I had the timing belt changed and the coolant was flushed (with green--this is what my mechanic wanted). At 180K, about 2 years ago I did a drain & fill, and this week makes my second.

FWIW, I have never noticed any heating problem with this car, at any time. Needle always stays at the middle after a few mins to get there.

Since about 180K, I have been pretty decent about keeping the coolant level in the overflow reservoir at the top mark.

I do not remember this at all, when I drained it 2 years ago, although b/c that was my first time, I suppose I might have missed it, but I doubt it---at that point, I was looking for bubbles, just like I was yesterday.

So is this anything to worry about?
 
Last edited:
Is it a paint flake? I've seen a few of these floating around in the coolant of my motorcycle. I didn't figure out what it was until I removed the radiator and saw some paint missing from the inlets and outlets where the hoses contact. Most of the missing paint adhered to the insides of the hoses at the contact points, but some of it made its way into the coolant.
 
I'm not sure about paint or not, but nobody here seems worried at all, so I won't be worried about it. Thanks. As this is only my second drain & fill, I had very little experience to draw upon.
 
Status
Not open for further replies.
Back
Top