Black Flaky Tar in Coolant

[BavarianZHP]

^^^ Indicator is white... Time for that overhaul!

[BavarianZHP]

Yep, there was also white residue that I had to clean out around the lip of the cap.

[BCS_ZHP]

Okay, your black substance may be the seal from the water pump. Once it starts to go, the water pump impeller can wobble a bit on its shaft which further deteriorates it. It's logical that particles from that eroded seal would collect in your expansion tank. I believe your problem is the cooling system, not your head gasket, at least that's what I'd start with. I suspect when you do get the water pump off, the shaft will flop around and you'll be amazed that it was still functioning while being that loose. There's a weep hole on the bottom of the water pump that starts to leak when this seal goes bad, so that why you had to add almost half a liter today. ECSTuning had a cooling system overhaul kit, at a minimum do the hoses, water pump, thermostat, heat sensor and cooling tank. If you're over 100k miles, add a radiator too. Replacing tensioners and pulleys too since you're in there, is a judgement call based on mileage.

[BavarianZHP]

Here's the pic:

[BavarianZHP]

Thanks for the input all, I'd be lost without you. The car just has 65k miles, no water cooling system overhaul - and I was expecting I would have to do it soon. Hopefully that's my problem.

[BCS_ZHP]

Okay, the bobber at the bottom is supposed to be white but the "thermometer stick is supposed to be dark blood red. A BMW tech told me that is the telltale sign of an impeding cooling system failure, normally the expansion tank goes first, then the water pump or thermostat. The white residue around the neck tells me your cap is going bad, the rubber may look okay but it's letting vapor seep by when the coolant is hot.

A cooling system over haul is a DIY, about $500 in parts and 4-5 hours to complete. There's a great DIY set of instructions on here somewhere, I set my iPad on top of the engine and followed the step by step photos to do my first one. Do you have a manual or automatic, there awesome special wrenches required for an automatic?

[BCS_ZHP]

#are some, not awesome

[BavarianZHP]

Ouch, $500 just after I blew my money on presents! :'(

It's a manual.

[BavarianZHP]

Found the parts list (see link). the DIY is great. I've looked at it before.

http://www.zhpmafia.com/forums/showt...ystem+overhaul

[danewilson77]

Ouch, $500 just after I blew my money on presents! :'(

It's a manual.

You can get level II kit for 3 and change. Also use BMW blue coolant. Looks like you got green in there now.

Prestone?

Sent from Williamsburg, VA USA