if I take the headlight out, yes that part would be open for a direct blast. LOL, That stain bothers me too, I haven't investigated it yet though. Probably just needs a good cleaning

 

Mine has the same stain also but my truck has quite a few more miles on it (185K)

 

maybe one of the gm tech guys will chime in if it's true or not, but I heard...ready for this...it is common on mid mileage vehicles as far as gm says. Whatever the hell mid mileage is. High mileage and the resevoir should start to fog up heavily.

Hooray for not "choking the radix"! Keep the chicken jokes to yourself!

 

i dont know about what gm says but your coolant system has what is called the "beach head" affect. This is like at the beach the tide brings up trash to the highest point that the water will go and then the water will go back out leaving the trash. That is like the coolant, all the corrosion in the system will flow till it finds the highest point and then kind of be "washed up" and left. This is why you see all the coolant tanks and older style radiator caps dirty.

Maybe this will help.

 

excellent info, is this "beach head" easy to clean out or does it even matter?

 

My stock Radix tube fit my 90mm TB perfectly

 

haha awesome info. So my guy was right. Expect staining due to all the bad stuff floating up.

 

Hmmm maybe mine is different because it's an aftermarket throttle body.

 

you can clean it all you want, its just going to come back. just whatever makes you sleep at night