black gunk inside upper intake manifold

[Rhett]

The other day I had my air tube off and was cleaning the TB. Opening the flap, and shining a light inside the upper intake manifold, I saw that there seemed to be some black deposits on its walls. Is this anything to worry about? What's the best way to clean in there? I have some TB spray and I am thinking about spraying it in there, but I won't be able to reach in there to wipe anything off. I don't want to do anything to harm the gasket; the TB cleaner I use is O2 and TB coating safe so that's not a concern. But I don't want to do anything to harm the gasket.

 

[leebo]

that's normal. It's a mixture of carbon, dirt, and several other things. A TB cleaner should be fine to use in there(that's what it's made for), but just don't get carried away. A small squirt should be fine.

 

[AgExplorer]

Rhett,

If you really want to get it clean, use AMSOIL's Power Foam. Just use as directed on the can. It will not harm the gaskets, TB coating or O2 sensors. I have used it twice on my '95 with great success.

 

[Rhett]

The TB is clean; it's the upper intake manifold that's dirty. I wish I could reach in there and wipe it down with cleaner, but I guess I will just have to spray it in there and hope it magically cleans itself. A curse on EGR! If it wasn't for that it wouldn't get very dirty.

I just wasn't sure if TB cleaner was ok to spray inside the upper intake manifold; I assumed it was since it's O2 and TB coating safe.

G. I know about Power Foam, but I already have this STP TB cleaner so I might as well try it first. I do need to place another order with AMSOIL soon for other products so I may throw in a bottle Power Foam.

 

[Alec]

This may sound like a dumb question, but why don't you take off the upper manifold to clean it? It's really easy to take "the octopus" off the top of the engine. You just have to make sure to seat the gaskets properly with reinstallation and torque the bolts to the correct specs.

 

[Rhett]

The reason is, I have never taken the upper intake manifold off of any engine before. So I think it's only natural that I am leery of doing that. With my luck I would @%#^ up the gasket seal.

Changing plugs; wires; cleaning TB; replacing fan; flushing the rad; even changing a stat; that stuff I can do. But when it gets any deeper into the engine than that, I get nervous. Probably due to my lack of experience more than anything else. Perhaps in a few years I will feel more comfortable with it.

but true, I know if I did pull the manifold I could do a number on it and have it really clean.

 

[Stephen S]

That would be my suggestion too, just take it off and clean it. My dad and I have had the upper and lower intake manifold off his 91 F-150 ( 302 V8). It's not too bad, but it's also not a 4.0 V6. I've never had mine apart, but I wouldn't think it woulkd be too bad either. I noticed mine is all gunky in there too, so I may tear into it during the summer when I have some time.

 

[Alec]

Go for it!

I say go for it! It's only 8 or so bolts and should easily take you less than 2 hours to take it off, clean it, and put it back on. As for the gasket, go ahead and get a new one from Autozone or Pepboys. The gaskets deteriorate anyways and often go bad. You shouldn't have a problem seating the new gasket. Just make sure you torque the bolts down to the correct specs when you put the manifold back on. And tighten them in stages, don't do one all the way then another, etc. Also, be very careful not to drop anything into the engine while it's exposed. It might help to put some shop rags in the lower manifold openings while the top is off.

Just a side note, the engine bay looks really funny when you have the top of the engine off. It just looks like someone threw a hole bunch of junk under the hood and coated it all with some nice grease. I have some good pics on photopoint

 

[FMNavajo]

Alec and Stephen S. are correct, take the upper manifold off and clean it out. I had never done this before and I did it in just a few hours in my garage with simple hand tools and my Haynes manual, the entire procedure is in the book. The gasket kit only cost around $50, I used Fel-Pro. When putting the gasket back on make sure you follow the procedure and apply silicone gasket material only were specified, in the corners by the water ports, and use the correct torque sequence as described in the manual. The gasket kit comes with all the gaskets you'll need including the fuel rail gasket.

I suggest getting your manual out and go over the procedures and obtain all the parts and materials needed prior to turning a bolt. This will probably increase your gas mpg as well.

FM