today, i replaced coolant tank because of leaks. while i was replacing the tank, i noticed that the previous coolant was little thicker than water and color was kinda brown. I've seen this symptom before and i heard that it could be mixing with the oil and it could be head gasket leaks. I've check the oil cap if there is residue on cap but everything looked normal and i even checked the oil dipstick and it was normal as well. I don't know what else i need to check and what am i supposed to do with this.. Coolant flush? Please advise.

 

Have you notice if there was more of an oil loss than normal ?
If the oil cap and dipstick is showing ok, I'd see if there was anything showing in the radiator by trying to drain a little coolant from the bottom.

 

If it walks like a duck, quacks like a duck . . . . .

Chocolate milk is not found in a car unless the coolant has mixed with the oil. Get a business car, put a drop or two of your milk on the card. Let lay flat for a couple of hours. If there oil in the mix, the oil will move/migrate outward from the center leaving the remaining materials in the middle. A single color stain, most likely no oil, two color stain with a darker center, chance are oil.

 

My guess is to check the heat exchanger, they can leak oil into the coolant.

https://www.northamericanmotoring.co...il-cooler.html

 

2X ECSTuning

 

I guess i might have to check oil level when i get home today.

 

is it hard to install?

 

would it be hard to install DIY?

 

A little bit of work but you can access from the one side.

https://www.northamericanmotoring.co...n-coolant.html

https://www.northamericanmotoring.co...in-an-r53.html

 

Except that it is in a bit of a difficult place, you can DIY.
Make sure to read this post:
https://www.northamericanmotoring.co...n-coolant.html