The cooling system was neglected by the previous owner in my Grand Marquis, and took a good couple of flushes before the system looked clean.
A while back, one of the coolant gaskets on the intake manifold failed (driver's side, near the brake booster) and I have to add about a liter or so of distilled water every 3 weeks or so. So I do not upset to 50:50 ratio, I add Motorcraft G-05 instead every third or forth time and keep an eye on the ratio with a Prestone coolant concentration tool I bought. It's a very minor leak, and does no harm. I haven't corrected the problem, because I decided it will work to my advantage - help clean up the cooling system very slowly.
When I checked the coolant level this morning, it was about 500 ml low and instead of adding distilled water, I used an extractor to remove all the coolant in the reservoir. I added 2.7 liters of distilled water to compensate.
The coolant I extracted looks rather mucky and brown in the container I used. When you take a small sample, it looks lighter. But otherwise, it looks very dark...almost a very dark orange-brown color. Here's a 200 ml sample (apologies about the lighting):
I was wondering what would cause the coolant to go dark like this. Initially, the coolant was a very nice, bright yellow color and I would have assumed it would stay clean with all the fresh stuff going in.
A while back, one of the coolant gaskets on the intake manifold failed (driver's side, near the brake booster) and I have to add about a liter or so of distilled water every 3 weeks or so. So I do not upset to 50:50 ratio, I add Motorcraft G-05 instead every third or forth time and keep an eye on the ratio with a Prestone coolant concentration tool I bought. It's a very minor leak, and does no harm. I haven't corrected the problem, because I decided it will work to my advantage - help clean up the cooling system very slowly.
When I checked the coolant level this morning, it was about 500 ml low and instead of adding distilled water, I used an extractor to remove all the coolant in the reservoir. I added 2.7 liters of distilled water to compensate.
The coolant I extracted looks rather mucky and brown in the container I used. When you take a small sample, it looks lighter. But otherwise, it looks very dark...almost a very dark orange-brown color. Here's a 200 ml sample (apologies about the lighting):
I was wondering what would cause the coolant to go dark like this. Initially, the coolant was a very nice, bright yellow color and I would have assumed it would stay clean with all the fresh stuff going in.