Prelude to a head gasket failure ???

[Derek A.]

I was filling up today and was checking underhood. Have been getting on occasional low coolant warning. I look in the reservoir and the fluid color is red/brown. Its not gooey or slimy, but I run BMW blue coolant - so I wouldn't expect the color to be anything but blue. Car is running ok, not overheating. Dipstick looks clean..anything else to check ?

[JD525IA]

Mine looked like that before I replaced the radiator and flushed the coolant system.

Of course, I tried to fix a bad radiator with some radiator leak fixing chemical, which sorta worked, but made the fluid turn reddish brown.

JD

[Derek A.]

Coolant is not that old in the car. I just did a thermostat a few months ago.

[The Bigfella]

Start the car up from cold with the water fill cap off. Let it idle for a minute and then smell the overflow tank. If it smells like unburnt fuel = problem.

[ryan roopnarine]

sounds like you have teh rust.
might be time to use teh acid (radiator cleaner).

take a picture of this residue for us and post it .

[bsell]

I was filling up today and was checking underhood. Have been getting on occasional low coolant warning. I look in the reservoir and the fluid color is red/brown. Its not gooey or slimy, but I run BMW blue coolant - so I wouldn't expect the color to be anything but blue. Car is running ok, not overheating. Dipstick looks clean..anything else to check ?

Bad things as seen from the radiator opening:

Dirty rusty brown coolant without oily stuff=rotting iron/aluminum dropping stuff into the coolant, results from never changing the coolant or not opening the heater valves while draining/flushing a dirty coolant system. Or you got hosed by the previous owner's cheap attempt at fixing some coolant leak with 'stop leak' crap.

Smells like wet exhaust=combustion gases entering cooling system (cracked head/block or bad head gasket if you are lucky) usually combined with swollen hoses or hoses that 'pop off' from overpressure. Spark plugs may or may not look different depending on the location of the leak. If you find a ‘steam cleaned’ one, you got coolant getting into the combustion chamber.

Coolant disappears without a drop on the ground=leak on the intake side (gasket at the throttle body for heated throttle body systems), cracked head in the intake area (vacuum), or bad head gasket causing leak into combustion chamber during high vacuum conditions. Confirmed by perfectly clean spark plug when compared to the other cylinders.

Snotty chocolate sticky goopy crap=oil in the coolant from bad head gasket/warped head due to overheating, water/oil cooler leaking and transferring fluids between themselves, or you are unlucky and have a cracked head between a pressurized oil passage into the coolant passages (pretty rare). Usually, this is accompanied by engine oil that looks like some mighty tasty chocolate milk but not always. Spark plugs may or may not look steam cleaned or really nasty from oil fouling. It just depends on how bad things are or the location of the trouble.


I would try another coolant flush and refill paying attention to the heater valves to ensure you get everything swapped out. If you get the same mud after all is said and done after doing a fabulously thorough flush job, you have got something made of iron that is really far gone and is repeatedly fouling your coolant system or a former owner poured tons of 'stop leak' into your system and it is slowly coming out.

Best of luck,

Brian

[Derek A.]

Upon closer examination. There doesn't seem to be a ton of sludge. Its more of a color discrepancy. The coolant has gone from blue to purple. I have been running blue coolant now for three years. Between a water pump, a full hose change and a thermostat change. I have flushed enough stuff through the system to eliminate other previous coolant types.

I did have to had about a half a quart this week. Dipstick is still looking clean and the car runs great.

[bsell]

Upon closer examination. There doesn't seem to be a ton of sludge. Its more of a color discrepancy. The coolant has gone from blue to purple. I have been running blue coolant now for three years. Between a water pump, a full hose change and a thermostat change. I have flushed enough stuff through the system to eliminate other previous coolant types.

I did have to had about a half a quart this week. Dipstick is still looking clean and the car runs great.

All right so blue + red = purple on the old color chart so who put the cherry Koolaid in your coolant?

Or is that Jimmy Hoffa's blood mixed in there?

What brand is the blue coolant? Maybe some Googling is in order for similar issues in other cars...

Brian

[Jon Shell]

Any steam or smoke out the exhaust pipe? If so, might be head gasket, warped head, crack in water jacket or head. The idea about sniffing for fuel odor in the overflow tank is a good one.

[Derek A.]

Neighboors must think I am . Laying over the front end of a BMW with your nose in the coolant recovery tank while the engine is running.

No exhaust smell, resampled the coolant. Color is consistent and no trace of oil. Must be a case of the coolant freaking out.

The stuff that is in there is the Pentosin/Hepu blue long life coolant.