Black Flaky Tar in Coolant

[BavarianZHP]

I checked my coolant level today (had to add 400 ml ) and noticed that there were black, flaky tar-like substances clinging to the level indicator (the flat, white platform of the indicator). It's like speckles of dirt covering most of the platform... It seems like engine tar, but there's no discoloration of the coolant. I'm worried it could be the head gasket.

Anyone have this issue or know about it?

[danewilson77]

Ugh. How is the car running?

Sent from Williamsburg, VA USA

[BavarianZHP]

Car runs fine, and has been without any hiccups of any kind. Temp has never gone above the half-way point, although it's winter now so overheating shouldn't be a problem. I just bought this thing and didn't notice it until now.

[BavarianZHP]

Oil level has stayed at full ever since I've owned it (just about 2 wks now).

[danewilson77]

If oil looks fine.... I would say conservatively speaking you could have it tested. You could also have a coolant flush performed and start fresh. There may just have been some foreign material introduced into the coolant system at some point.

Has coolant overhaul been performed? Could it be some broken down oring material?

Sent from Williamsburg, VA USA

[BCS_ZHP]

Check the rubber seal on your expansion tank cap, that's a known weak point and the rubber there will deteriorate due to thermal cycling and let vapor seep by. Open the cap when the engine is cold, rub your fingers roughly around the cap seal and see if it flakes off into your hand. So your coolant loss and the tar(rubber) substance may be this cap telling ou it's time for replacement. These caps are such a weak point, in my opinion, and they're less than $10, that I normally keep a spare one in the cabinet in my garage.

[BavarianZHP]

Oil looks fine - no milky residue, haven't checked the exhaust color while revving the engine though. I guess it could also be the hoses corroding? Whatever it is, it's a bad sign - probably HG failure?

[BavarianZHP]

Not the cap, Just cleaned it. I wish it was...

[BCS_ZHP]

And if it is the cap, you likely will see some white residue evidence on the expansion tank around the neck of the opening where the cap attaches.

[BCS_ZHP]

Your fluid level stick, what color is it, should be dark blood red. If its pink or even white, then time for a cooling system overhaul.