[Smonkey09]

This may be a silly question, but why do CBU issues impact the intake components so much more than the exhaust-side of the engine? Is it because of the higher temps of the exhaust-side of things not allowing the oil vapor to condense and/or high temps burning off carbon?

Funny, I used to love working on my car as a teenager. Took shop classes all through high school. Now with my warranty expiring plus maintenance plan ending on my first "real" car, I've spent at least 80 hours catching up on 15 years of new engine technology (and related issues)! My SES light came on for the second tie in two months and the supposed "best" independent shop in Chicago replaced my MAF sensor. Light came on again, and it is throwing other codes (EGR and injector related) that, per you folks in the forum, pointed me to the CBU issues. Now I'm investing in all the tools necessary to do the CBU cleaning myself, since I have lost some trust in the local pros.

(Best part is, wife thinks it is sexy that I'm learning so much about the car and how to fix it myself. Found the right woman.)

[Hoooper]

I would say it gets fully burnt in the exhaust side which gets much hotter obviously than the intake side. If you could take a torch to the intake it should all burn right off. There was at least one member though who had a turbo replaced due to being caked full of build up, but that seems to be a one of a kind case

[Smonkey09]

It only it were an aluminum intake without swirl flaps and other craziness we could burn it clean. :-)

[Mik325tds]

Yeah, that's how the did it on the old VW diesel engines with aluminum intakes. Take a look at this crazy vid:

But that still leaves the intake swirl ports in the cylinder head.

[Smonkey09]

Originally Posted by Mik325tds

Yeah, that's how the did it on the old VW diesel engines with aluminum intakes. Take a look at this crazy vid:

But that still leaves the intake swirl ports in the cylinder head.

Ha! I ran across this when doing research on various DIY methods of cleaning the intake.

Seeing all that hot carbon flying around reminded me of the days I worked in an exhaust shop, using a torch to cut off clamps and getting molten iron everywhere. I soon learned to not tuck in my shirt. Too often I'd get sparks down my shirt via the collar and with the shirt tucked in, they ended up where they shouldn't have gone.

[dixy2k]

It gets trapped in the exhaust as well. When regens don't happen the right way (read many incomplete cycles) it all adds up and even the turbos get dirty too.