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View Full Version : What is this in my coolant?



Rus
11-13-2006, 05:32 PM
Hello everyone!

When I opened the expansion tank cap today I was greeted with this view:

http://zakm.hotbox.ru/BMW/IMG_0193.jpg

Could this be oil? I sincerely hope not and the car gives no indication of a faulty head gasket. The coolant color is actually the BMW blue as it should be, but the small little specks floating on top, and throughout the reservoir, are bothering me. Now the fact that these particles are not contained to just the surface of the liquid makes me suspect that they aren't oil-based. Furthermore, when I removed some of them with my finger they literarly disappear on touch and leave no oily residue of any sort. The oil in the engine is new and shows no coolant contamination. Old oil was in the car for about three thousand miles and also showed no coolant contamination. The coolant is nearly new and in proper mix ratio. Thermostat, all hoses, clamps, expansion tank cap, and thermostat are all new. The engine was flushed with water twice before receiving the blue coolant. Previously the cooling system was filled with generic green coolant. The plugs showed no steam-cleaning on last removal (~2K miles ago) and the exhaust has no white smoke or antifreeze smell to it. I have also noted that my coolant level seems to drop to just below the arrow on the reservoir if I fill it to the mark. There is evidence of coolant in the external drain channel around the reservoir cap which I suspect may be draining off excess coolant during operation. When the engine is hot, the coolant level occupies the entire reservoir, again leading me to believe that any excess that is dumped in is discharged through the bottom tube in the picture (goes to the passenger side firewall).

So, question 1:

What can these particles in the coolant be?

Question 2:

Does my coolant drain theory hold up to the wisdom of the collective mind?

Thanks in advance!

TC535i
11-13-2006, 05:34 PM
That doesn't look like oil... oil will give it a greasy slick look (think oil on water), or make the thing look like a chocolate milkshake, depending on the amount of oil. Our 735 looked like an Irish Carbomb when I opened the cap (the drink, not the IRA weapon... Guiness + shot of Baileys/whiskey).

Rus
11-13-2006, 05:40 PM
I'll have to remember that analogy :) Could it be just particles from the many rubber parts that I installed? I'm pretty sure I didn't pre-wash any of them before installation. Thanks for the quick response!

E34 530
11-13-2006, 05:42 PM
It could just be some dirt particles from the last time the coolant was replaced, but hopefully they are not small metal shavings.

Rus
11-13-2006, 05:44 PM
It could just be some dirt particles from the last time the coolant was replaced, but hopefully they are not small metal shavings.

I've fished some of them out and they are definitely not metallic in nature (phew). That would make me suspect the brand new water pump which only has about 2K miles on it.

TC535i
11-13-2006, 05:54 PM
Almost looks like flakey rust... you say it's not metallic tho?

DaveVoorhis
11-13-2006, 06:06 PM
Did you use tap water last coolant change? Might be mineral deposits.

SnakeyesTx
11-13-2006, 08:03 PM
Looks like calcium or some other kind of scale built up. I've had that stuff too. I've got no cooling issues. The oil as previously mentioned will look muddy/milkshake like.

Blitzkrieg Bob
11-13-2006, 08:33 PM
http://www.bimmer.info/forum/showthread.php?t=26228&highlight=spank

Originally Posted by winfred
i spank off in mine sorta like evans




on your car?

jgardia
11-13-2006, 08:49 PM
I think is very difficult to have metal pieces floating in the coolant... unless your coolant is veeery dense... ;)



Almost looks like flakey rust... you say it's not metallic tho?

Rus
11-13-2006, 10:17 PM
I used distilled water during the coolant change, but I have no information about what exactly was used in the system before. It may very well have been regular tap water and whatever green coolant was available. I'm thankful that at least its not oil in there. I guess now I'll just have to sort out the vanishing coolant concern.

brick8
11-14-2006, 09:44 AM
Looks like barsleak or some similar product. Some people put ground pepper in the coolant to stop leaks too.

Rus
11-14-2006, 10:03 AM
Looks like barsleak or some similar product. Some people put ground pepper in the coolant to stop leaks too.

I know I never put anything of that sort in the system, but there's no guarantee that the PO didn't do it. The car had a leaking water pump when I got it, so perhaps it is some old "remedy" resurfacing despite the flush that I performed when I changed the coolant.