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I have a earlyish (Dec 2013 build) MY14 E63 wagon. Did the usual 5K mile oil change yesterday, checked all my suspension bushes and fluids, and then noticed my coolant changed from blue to gold. First thing I thought about was blown head gasket and combustion vapors... Bought the typical Lisle kit (my advance auto didn't have one to rent...weak). Checked it as per instructions this AM.... had good vacuum source, nice bubbles all the way through the test, good seal, did the test 3 times consecutively to make sure I'm not losing my mind - no color change with the test fluid.
Long story short... why did it change color? No change in operating temps, level may have dropped slightly, but nothing that would give me worry, 8 oz or less, but that's happened through my ownership before. I've had this car for 3.5 years, but I've never replaced the coolant. Is this the car telling me the coolant's effective life is used up? Next step is probably a flush and fluid replacement, then monitoring., unless someone has a similar experience and knows something's up.
Do some coolants change color based on time and heat cycles? I did not put that gold looking fluid back in the reservoir, I replaced it with fresh OE MB fluid and de-ionized h20. Thanks in advance. test fluid color after 3 consecutive tests this photo looks worse than it was in the beginning. Originally I dumped the nasty looking coolant into a used mobil 1 bottle - then realized I didn't take a photo... still captures the hue but it was considerably clearer
I too would expect to see the "milk shake" if it were oil. How about this long shot....original water pump has plastic impeller, many replacement units are steel impeller, with 135k miles, probably a replacement, As the water pump bearings on these pumps wear the pulley starts riding out, you can see it by looking at the contact patch between the belt and the pulley, if it rides out enough the impeller will rub on pump housing releasing aluminum and steel into the coolant pretty quickly possibly changing the color (iron oxide)...
I too would expect to see the "milk shake" if it were oil. How about this long shot....original water pump has plastic impeller, many replacement units are steel impeller, with 135k miles, probably a replacement, As the water pump bearings on these pumps wear the pulley starts riding out, you can see it by looking at the contact patch between the belt and the pulley, if it rides out enough the impeller will rub on pump housing releasing aluminum and steel into the coolant pretty quickly possibly changing the color (iron oxide)...
Dang, didn’t even think of that. Glad I changed my wp out earlier in the year.
Dang, didn’t even think of that. Glad I changed my wp out earlier in the year.
Did mine once I hit 100k along with all my pulleys, belt, and thermostat as preventative maintenance. But did notice that my pulley was starting to walk out too.
old coolant just looks like that. The corrosion inhibitors start going out, and the stuff isn't as efficient anymore at the 10 year mark which is exactly when you changed it. The lifespan of the fluid is 10 years IIRC but that figure can change WILDLY depending on how hard you work it. Carry on.
If you have a cast-iron block car the coolant starts to turn into mud over a period of time as the inhibitors start to give out. This is the much kinder version of that.
Heres some old coolant which is doing what I said it does. The Mercedes stuff turns into a sweet tea color exactly as you've shown, it's picking up corrosion from.. whatevers in there. I'm not a metallurgist and it's late but you're FINE.
old coolant just looks like that. The corrosion inhibitors start going out, and the stuff isn't as efficient anymore at the 10 year mark which is exactly when you changed it. The lifespan of the fluid is 10 years IIRC but that figure can change WILDLY depending on how hard you work it. Carry on.
If you have a cast-iron block car the coolant starts to turn into mud over a period of time as the inhibitors start to give out. This is the much kinder version of that.
Heres some old coolant which is doing what I said it does. The Mercedes stuff turns into a sweet tea color exactly as you've shown, it's picking up corrosion from.. whatevers in there. I'm not a metallurgist and it's late but you're FINE.
Thanks for the reply Chris. Also because my car does sit for extended period of time (merchant mariner) I wonder about fluid sitting dormant, not circulating. I just fired up the heater in the car the other morning, maybe some nasty fluid sitting in that circuit that was being bypassed for months? Looking back in my records I don't in fact believe the coolant was ever replaced... seems about time....
Thanks for the reply Chris. Also because my car does sit for extended period of time (merchant mariner) I wonder about fluid sitting dormant, not circulating. I just fired up the heater in the car the other morning, maybe some nasty fluid sitting in that circuit that was being bypassed for months? Looking back in my records I don't in fact believe the coolant was ever replaced... seems about time....
just change it and pull samples, the color is the best way to determine coolant health. The color represents the ability for the coolant to hold heat, lubricate, keep seals fresh, and replacing it puts less stress on the oil, which is the engines first line of defense against heat.
this is a headbolt failure with an obvious head gasket failure. Itll leak combustion into the cooling system and propel oil and pressure into everything and push this mixture of stuff into everything. You would see it in your oil, coolant, and youd be misfiring quite badly immediately. This is not a catastrophic failure. Cars totally fine.
oh and if your car sits for months please use a fuel stabilizer the water buildup/separation in fuel can hurt/corrode the metal parts of the fuel pump over time, cause injectors to stick, etc. it's just a safe precaution
just change it and pull samples, the color is the best way to determine coolant health. The color represents the ability for the coolant to hold heat, lubricate, keep seals fresh, and replacing it puts less stress on the oil, which is the engines first line of defense against heat.
this is a headbolt failure with an obvious head gasket failure. Itll leak combustion into the cooling system and propel oil and pressure into everything and push this mixture of stuff into everything. You would see it in your oil, coolant, and youd be misfiring quite badly immediately. This is not a catastrophic failure. Cars totally fine.
oh and if your car sits for months please use a fuel stabilizer the water buildup/separation in fuel can hurt/corrode the metal parts of the fuel pump over time, cause injectors to stick, etc. it's just a safe precaution
Been using ACES IV for years... good product. Brian is a Tribologist and loves to talk. If you ever wanted to nerd out with someone over additives and fluids he's your man, his company is BND automotive. Apparently he's quite popular with the mopar crowd.
Called my Indy today and they are backed up 3 weeks with work. Discussed this over the phone and he confirmed I should flush out the coolant and replace with fresh. I also ordered a blackstone coolant sample kit, just curious to see what a lab would say.
11-05-2023, 10:49 AM
