Hi all, I'm new to this forum, I've owned a 2006 lancer evo 9 in Malaysia for over 6 years now!
Engine has been built 4 years back, Has around 40,000km on it now.

My car is built with a 2.0 forged bottom end, with regular bolt-on on the head. GSC S2 cams, Zero Thick Lifters, GSC beehive retainers, GSC Titanium Springs, With a AEM Adjustable pulley on the Exhaust side.

After the rebuild. Im getting weird symptoms whenever I track my car. After every track day at Sepang (Malaysia). I will lose a significant amount of coolant ( 100% there are no leaks on coolant lines, radiator and pressure cap).

during every track day, I will find a mix of engine oil & water(suspecting it's coolant) in the oil catch can. The mixture is (milky light brown colour)

I had removed the AN fitttings from the Cam cover(leading from Cam cover to catch can) . I found left over gunk/ Sluge residue of water and oil mixing on the fitting(Cam cover bung). So with that I can confirm water is mixing with oil somewhere within in the engine oil passage.

The weird thing is the engine oil in my oil pan is still regular dark brown/ blackish colour (like how any normal engine oil would look like)
My question- if the coolant is mixing into the engine oil. Why isn't the rest of the engine oil becoming milky light brown?

Another unusual thing about my engine. There is a lot of carbon/ oil stains on all the components under the cam cover. the shop that I rebuild my car at told me it was normal. But I know it isn't normal. As my stock engine before the rebuild had done 200,000KM and it wasn't even half as dirty/ Black as it is now. I will attach photos to give you guys a better understanding.


with all this weird symptoms I had gone for 4 track days all 4 times I had the same issue. Losing coolant and water and oil pouring out my catch can's breather while the ECT and OIL temps were all cool never once did it overheat.


Before my recent track day I thought I should do a dyno run to check if my tune was still it still made on 500whp at 26psi on a FP RED ss housing 93 pump gas on a Dynapack roller.




If anyone can share with me, any info on what I should be looking for. I would really appreciate it.

Thank you,
Juice9