Strange color when draining coolant
 

Hey guys! So I flushed my coolant today. It was mostly water with a little bit of coolant, so the coolant I drained was mostly clear with a light green tint. However, some times the coolant that came out looked yellow. I collected some to a bottle and took a pic.

Attachment 281524

I googled a bit. Some say it could be rust. Some say it could me oil. I don't know what this is.

Please help.

Don't worry about it, just change it with fresh coolant. The previous owner probably just never changed it and added who knows what. If you are worried about the cooling system, pressure test it or send in an oil sample to Blackstone.

Thanks and previous coolant change was done by me 2 years ago :lol: I used Wurth green coolant. However, last year I had to drain the radiator, and then I refilled it with distilled water. I ran out of bottles so the last liter or so was tap water. Maybe that caused rust?

I also lose about 50ml of coolant every 200 miles or so. If I leave it at the Full mark, it would be about 1-2mm lower after a 200 mile drive. Normal?

Well yeah you should never run straight water and the quality of distilled water car vary, it will still cause corrosion when you run it straight. These engine still show rust when torn apart, even on cars that have only run OEM FL22 their whole lives.

I flushed it until the fluid that came out was clear. I'll just change coolant more frequently I guess.

Is losing that bit of coolant normal?

No, you should not be losing any coolant. Just run actual coolant.

Coolant has corrosion inhibitors that water obviously doesn't. Also, tap water is an electrolyte and can cause dissimilar metals to erode.