1994 855 fresh head gasket rebuild, black coolant?

Post by **phat78ta** » 04 Aug 2014, 17:25

Got the wagon up a out on the road again drove her a bit yesterday. Didn't realize how much boost I was losing to the bad HG. This puppy MOVES!

Anyway, l noticed the coolant was a strange color, so I decided to drain it. This is what I have going:

I did install a new radiator(tank leak) and I am flushing the system as we speak.
What could be the cause of this?

Post by **j-dawg** » 04 Aug 2014, 22:43

narsty. is there an oily layer on top? doesn't look like it from the picture

Post by **phat78ta** » 04 Aug 2014, 23:04

No oil in the coolant, and smells like regular old coolant. Flushed it out 3 times, still got black color even with plain water. Idk what the deal is, gonna run by the local volvo guru tomorrow and see what he thinks.

Post by **rspi** » 05 Aug 2014, 08:00

When I flush the coolant system I usually have the thermostat out, bottle cap open, rad drain open, car running, while I'm pouring distilled water in the reservoir. I pour through 3 gallons before I shut it down and add in 100% G-05 coolant to seal the system.

Post by **Ozark Lee** » 05 Aug 2014, 08:21

Elaborate a bit on the head gasket replacement that led up to this. Did you send the head out to have it reworked? Machine shops usually clean the head as a part of the process and I'm not sure what solvents they use. Whatever "stuff" they do use it works great and the head comes back looking brand new. It could be residual "stuff" from the machine shop. If that is the case a flush should take care of it.

...Lee

Post by **phat78ta** » 05 Aug 2014, 09:14

I believe it is from the previous owner using a stop leak product. I had some of the plain water that I drained last night in a pan to see if I had any oil in the coolant. This morning the water was clear until I stirred it a bit. Then it turned black/brownish.
The PO pulled a fast one on me and sold a car with a known bad head gasket.I believe it is the bar's stop leak crap. I am going to continue to run plain water and clean it out as best that I can and then put coolant in it when it's clean.

Post by **erikv11** » 05 Aug 2014, 09:28

Yeah, the system is simply not yet clean. Flush it out until it runs clear, go from there, it should be fine. If it is indeed stop leak gunk then it may take longer to flush out. At the end do a complete, final flush with distilled water, drain and refill with G-05 like rspi suggested.

Post by **mecheng** » 05 Aug 2014, 10:40

erikv11 wrote:Yeah, the system is simply not yet clean. Flush it out until it runs clear, go from there, it should be fine. If it is indeed stop leak gunk then it may take longer to flush out. At the end do a complete, final flush with distilled water, drain and refill with G-05 like rspi suggested.

I second this, its okay to use tap water for the flush but make sure you don't have any left when its clear becasue it will clog up with cooling system with scale from the minerals. I would use a flush product because it looks pretty dirty.

Post by **northernlights** » 05 Aug 2014, 17:00

mecheng wrote:
erikv11 wrote:Yeah, the system is simply not yet clean. Flush it out until it runs clear, go from there, it should be fine. If it is indeed stop leak gunk then it may take longer to flush out. At the end do a complete, final flush with distilled water, drain and refill with G-05 like rspi suggested.
I second this, its okay to use tap water for the flush but make sure you don't have any left when its clear becasue it will clog up with cooling system with scale from the minerals. I would use a flush product because it looks pretty dirty.

While it's well worth flushing nasty stop leak out, don't panic about a little residual tap water. G-05, technically BASF Glysantin G-05, was designed to be compatible with slightly hard water. Mercedes sells cars all over the world, and often times the water quality wasn't the greatest.

This document page has some interesting specs on acceptable water quality for G-05.

Technically G-48 is what Volvo specified for the old stuff, but sadly you have to buy it branded from either Volvo or BMW, although I've found the BMW coolant at Carquest before. At least G-05 is close.

Post by **erikv11** » 05 Aug 2014, 17:53

Nice post! I was curious about this because I've never heard of it; the BASF document actually OKs using tap water.

So I did a little googling ... The federal limit in the US for both chloride and sulfate in tap water is 250 ppm, the state limits seem almost uniformly to be the same. Some local water supplies in the US report very low (single digit) ppms, but for some that I looked at (e.g. Omaha NE) you see levels above 200 ppm for both chloride and sufate. The BASF document says G-05 is compatible with a max of 100 ppm for either. I didn't look into water hardness.

Given those numbers, I completely agree with the "don't panic" comment about residual tap water with G-05, but still it may be prudent to flush and fill with a final run of distilled water.