Black Coolant

[Susan]

This picture is what came out of my bike's radiator last night. It feels slippery (not as slippery as cooking oil, just somewhat slippery), and it smells like caramelized sugar.

AFAIK, it might be the first time anyone has changed the coolant. The bike had 400 km when I got it and has 7K km on it now. Performance seems fine, good power, never overheats, no leaks, no smoke, no disturbing noises, nothing weird except the color/texture/smell of the coolant. The oil doesn't look milky or odd in any way. So I don't think it's a bad gasket or a crack somewhere in the engine.

I flushed it and added appropriate new coolant and I'll keep an eye on it.

The caramel smell makes me think the coolant got overheated at some point. Thoughts?

 

[Motogiro]

Coolant does have a sort of sweet smell and you will see warnings not leave any where animals and kids can get to it. A lot of cats especially like it.
I've never seen black coolant so change it out and make sure all the air gets purged so that there are no boiling spots where air could reside. Maybe refill with water first so as to flush it out and then the new coolant.

 

[FB400]

That sounds outright weird to have it be that color. I think the stock coolant Yamaha used was a dark bluish color. Maybe you are mistaking the color in low light?

I would recommend using a radiator flush given the condition of the coolant. It takes time and patience to do right but you might as well start out with a clean system

 

[david323]

I changed mine when I bought the bike (I honestly don't think the original owner ever did any maintenance other than oil changes). At ~5100 miles it was dark brown and nasty. I refilled with distilled water, ran for about 15 minutes, drained, refilled with more distilled water, ran for 15 more minutes, drained and finally filled with coolant (I opted for Engine Ice). I flushed twice to be double sure to get that nasty brown crap out of there.

 

[Gelvatron]

My buddy had a leak on his transmission cooler and his coolant looked muddy but smelt very sweet I'm sure it's mixed with something
Or like you said has over heated at some point just monitor it, and when you flushed it did you run soft tap water though it for a warm up cycle then flush and add 50/50?

 

[Susan]

I see I had an image fail when I first posted. I went back and put the picture in post #1. That is not Pepsi, it's my coolant (and is now labeled "Poison" in case anyone gets it in his head to drink it. Not a low-light issue, because I was in a well-lit shop.

I didn't run the bike with just water in it, but I did run the garden hose into it for a good while before refilling it, per dh's orders.

This wasn't a regular sweet smell, it was caramel sweet. It smelled exactly like dulce de leche (if you haven't eaten that, you need to, it's yummy). Even dh commented that it was weird, and he's been a mechanic for years and years and has never seen or smelled coolant like this. He said he's going to send it away to get tested.

David323, did yours ever turn a funky color again?

 

[ChevyFazer]

There is a couple things that could have turned it black. Someone could have mixed red and green coolants, Someone could have added some of that stop leak stuff (most likely) or which would be a long shot since you got the bike with 400km on it, it was ran on straight water for a while and things have gotten rusted up a bit.

 

[ChevyFazer]

After reading you last comment about the smell it might be a combo of red/green coolant mixed plus stop leak.

Can you see any damage around any of the cooling system or residue where something might have been leaking at one point in time to make someone put stop leak in?

 

[Susan]

After reading you last comment about the smell it might be a combo of red/green coolant mixed plus stop leak.

Can you see any damage around any of the cooling system or residue where something might have been leaking at one point in time to make someone put stop leak in?

Huh. I never thought of red plus green equals yuck. Good point.

I didn't notice any damage or evidence of leaks. I've been washing this bike for about a year now, and goodness only knows the things I haven't noticed. When I go out to the shop this afternoon, I'll get under there and have a good look. Thanks! :thumbup:

 

[ChevyFazer]

Something else I'll add is one of the cheapest most effective cooling system flushes is some good old fashioned cascade dish washing powders. It works like a charm!

 

[FinalImpact]

+2 votes on a mix. . . Adding that not all materials are meant to be mixed and can turn slurry'ish.

FWIW: I'd run it for couple weeks and dump it again.