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00+ Northstar Intake manifold...why so filthy inside?

1623 Views 9 Replies 4 Participants Last post by  Submariner409

After wrestling with the crossover gasket job, I was planning to change the plugs while the intake was off for that fiasco.

Unfortunately, the car got the best of me in round 2 and I decided to surrender to the plugs for another day.

Since I had the intake off, the plenum boot and seals were going to get replaced as well. Low and behold the throttle body was filthy and so was inside the intake manifold.

I guess the egr and pcv system work wonders to the inside of the intake manifold. Nonetheless, I thought this just might be the case maybe just with my car. So, I decided to head to the men's mall, since there was unfortunately a fresh kill on the list and try my luck.

Well, there was a nice 2002 with brand new strut in the front , brand new air shocks in the back and an overheated engine. Another fatality, anyway it dawned on me to retrieve the pcv hose on the back of the intake.

Interesting the things you find out when searching for other parts. Like the clip that holds the hose to the intake manifold was missing on mine.

So intake hose in hand I decided to peek inside this intake manifold, sure enough filthy. I wondered why in the world is this thing getting so mucked up. This can't be good for induction...... I took the whole manifold as a spare.

I will disassemble the manifold, thoroughly clean it and mount it to the car when swapping the plugs and then clean my original one later for the next time I remove the manifold.

Yet, this time I will monitor how long it takes to get that bad and what steps I can take to prevent it getting so filthy......
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I guess the egr and pcv system work wonders to the inside of the intake manifold.
crankcase and exhaust gases pass through the intake, get ingested and out the tail pipe, but when you shut down, they condense on the inside of the TB because it cools faster, which explains the dirty TB. The rest settles out and makes that nasty (but harmless) mess in the manifold
Not enough air flow under most driving conditions to accomplish that. Add to that the fact that is is simply not detrimental or important enough for the engineers to have worried about.
Think of it as a dirty exhaust system. Never gets cleaned and causes no problems.
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