2004 sx230 overheating & milky cream in vent tube

[WREKS]

Neither sand nor salt. That is biofouling. It builds up over time. Every time an engine is flushed, residual water remains. Microbes feed on the water and a layer of slime is the result. The slime dries out and settles to the bottom. After numerous flushes the water jacket gets impacted with the dead layers of slime. The buildup is soft near the top where the fresh living microbes are thriving, harder near the bottom where the dried out layers are piling on.

My remedy has been to dry out the cylinders after flushing when the engine is cold. Run engine for about a minute without cooling water. Repeating this process several times will dry out the cylinders and prevent biofouling from taking place.

BTW, that is Cylinder #1. It is the farthest from the cooling water intake, least likely to respond to flushing, and the most likely to foul first. That may be why the engineers placed the engine thermoswitch at that location.

 

[c_johnsonftw]

I learned something new, I’ve never heard of biofouling. You are correct on cylinder # 1 I was looking at it backwards. Is there a method to get this stuff out other than what I did? Or is bulling the head and chiseling it out the only way?

 

[WREKS]

Prevention is key. I have found drying out the cooling system is the best way. It layers in and hardens. Imagine trying to flush out paper mache. It needs water to build up so drying out the cooling system after flushing works best.