Filthy Intake Manifold

[adam4tw]

The valves in my intake manifold are filthy! They are CAKED with this black crap (carbon?). I have throttle body cleaner that I used to clean the throttle body out (the crap was caked on that good as well) and as far into the manifold as I could reach with a cloth. My check engine light was coming on a lot on the highway (even though the car kept running just fine) but when I use the TB cleaner and spray inside the throttle body and wipe that out good the check engine light will stay off for a while. I'm assuming this crud has something to do with that and I can imagine there is a lot of performance lost to this stuff. Is there anything I can use to clean that crap out without removing the intake manifold and soaking it? I believe a few years ago my dad had some stuff you spray into the intake while the car is running that cleans out the whole intake system, and he used that on my old car. I asked him what it was and where he got it and he can't remember where he got it, but I can't find it at any auto parts stores either!

[rixGAphx]

Genericly, it's called 'Top End Cleaner'.

GM used to have a very good formula, right on the shelf of every dealer parts department.
Haven't seen it in a while.

The general brand name is 'SeaFoam', and it's sold primarily for marine engines.
Every boat engine place has it.

See: http://www.seafoamsales.com/

There are numerous threads in 'Maintenance' and 'Problems and Solutions' about how to use it on GA's, do a 'search' for SeaFoam.
* * *

What 'valves' are you seeing that are 'caked with this crap'?

In the 3.1, you can't see any valves unless you remove the intake manifolds.
If you had the 'caking' in the intake passages, then I don't doubt it's also on the valves. But you can't SEE it (or the valves) with the manifolds in place.

Anywho, yeah, just run the can of stuff thru the Brake Booster inlet hose, per bottle directions.
It will clean the intake and valves.
* * *

Since you have so much crap in the intake, then your engine *prolly* has a completely-plugged Exhaust Gas Recirculation (EGR) valve and/or passages.
It's the metal can just behind the throttle body, mounted to the intake manifold. About the size and shape of a baby-food jar.

Remove, clean or replace, and also clean the passages serving it, reinstall.

Good luck.
-Rick

[adam4tw]

awesome thanks for all the info!

[Prospeeder]

You can stil get the GM stuff, its called GM Top end cleaner, you feed it in through a vacuum line like the brake booster

[adam4tw]

Well then I will have to check out the GM dealership over here. If they don't have it there I know there is an autoshop not too far from here that carries seafoam cleaner.

[themoo2112]

Now on the seafoam website, it says you can pour into where the PCV valve goes. I thought you can't do this??

[rixGAphx]

Originally posted by themoo2112
Now on the seafoam website, it says you can pour into where the PCV valve goes. I thought you can't do this??
Not on your V6, you can't.

They're talking about old-fashioned carb'd V-8 marine engines, where the PCV hose has two ends:
1. One at the valve cover (like our V-6's); and,
2 The other end connects to a 1/2" diameter vacuum port right under the carb; THIS is where the Seafoam can be introduced.

Our PCV valve (in the grommet in the valve cover) has just a tiny hose that eventually gets to the intake manifold, but it isn't suitable for Seafoam or Top End Cleaner.

Just use the brake booster line.

-Rick