About 3 months ago I noticed the coolant had a rusty color to it, so I did a coolant flush. I flushed the system 3 times as well as replacing the coolant and the stained expansion tank. The coolant was nice and pink for a few days but slowly began to turn rusty again.

I'm beginning to think flushing the system was only a treatment for the symptoms and not a cure for the problem. What is the likely cause of this? Radiator? Water pump? Engine block?

Soon I'll need to remove the radiator and radiator support panel for some unrelated maintenance, what's the best way to check these cooling system components for problems?

 

Chances are the coolant was once mixed with a non G12 mix. This causes a thicker consistence and a rust color. If it was like that long enough there is likely a fair amount of deposit in the system, and possibly corrosion and rust. Keep flushing it, but it may never get back to normal.

What did you initially flush it with?

Another possibility is that you have a head gasket leak and that oil is leaking into the coolant system.

 

Yikes.

I'll keeping flushing it and see what happens. I need to take the radiator off anyway though, do you think it could be damaged or corroded? Anything I should check for?

I just flushed it with water, do you think one of those cooling system cleaning solutions would do the trick?

 

how did you flush it? you should fill it with water, let it get up to operating temperature so the thermostat opens and it flushes out the radiator, then let it cool a little bit, take off the upper radiator hose and put a garden hose in it and let it flush it all out thru the bottom drain. refill with water and do that again. then drain it and refill with coolant.

 

I followed the DIY, it even said to use distilled water. Is that really necessary? I did everything except for putting the garden hose in the upper radiator hose.

Should I use a cooling system cleaning solution? If so, will they all do pretty much the same thing? Are there ones specific to G12 coolant?

 

use a cleaning solution, defiantly do the part with the hose, it's the biggest part. don't forget to let it chill for a min first though, wouldn't want to chill a hot engine that fast.

 

distilled water is only necessary if its going to be in the engine for a long time. if your just flushing it, the water is fine as long as its clean enough to drink.

 

Ok, thanks.

 

yeah, they only suggest distilled water to mix with coolant to obtain your ratio for normal driving. This is because it contains no mineral content and will not leave deposits in the system.

 

I know it's been a while, but is it ok to use one of those cooling system cleaning solutions on our cars?