I just purchased a used LS6 intake with about 20,000 miles on it. I am wondering if I should clean out the insides before I install it, and if so what kind of cleaner/solvent I should use that will not harm the plastic.
Thanks,
Bob

 

definalty clean it esp the inside use hot water and dish soap and a bottle brush if its a bare intake. if all full of electrical gizmos use seafoam in a spray bottle. i bought some at autozone about 9 bucks

 

Bottle brush...good idea. I guess a solution with Dawn dishwashing detergant should work, since the intake is bare, but what is Seafoam, an intake cleaner?

 

If you can get your hands on compressed air, that would be a great idea as well.

 

I'd pull all the sensors and gaskets off, run it through the dishwasher, then put new gaskets on.

 

I was planning on replacing the gaskets. Should I give them a light coat of silicone (Sil-glide) grease before installing them?
Although the dishwasher sounds interesting, my wife would surely take exception to that.
thanks

 

You must not be married

 

Of course not! I just washed my alternator bracket, valve covers, idler pulley thing, motor mounts, and some other stuff. Works great!

 

Sure hope you're drinking your brew from a Dixie cup

 

Can anybody tell me about "Seafoam" and if it would be good to use for the cleaning? I guess I could just use any old intake cleaner spray and compressed air too.

 

It's best not to use silicone on any gasket that might touch air going to the engine. That stuff is indestructable, and can run through the engine and give your O2 sensors a fit. It will also clog injectors if used on the injector o-rings (I know this the hard way).
Use a light coat of motor oil on the gaskets, per the GM manual.

Do a search for Seafoam. It's an internal engine cleaner, probably similar to Chevron Techron, that breaks up deposits and carbon in the cylinders, and in the crankcase. It won't hurt the manifold or the electrical/sensors.
But don't add it to your wife's dishwasher (HeHe).

DG

 

Don't forget to have some Z06 style water crossover lines on hand before you tear her apart. That manifold will not sit down on top of your current water line set-up. You'll also need to ditch the two green plastic wire harness clips holding your knock sensor wires.
It's an easy job though.

 

Seafoam is great for cleaning and will do the job the right way the first time. I would be careful of any cleaner spray as it can dis color the intake manifold.

 

NOT MARRIED......hmmm.....WONDER WHYYYY....!!!!

 

Thanks for the tips! I take it you have done this swap already? I ordered the water lines from Gene Culley and I am ready to go with the install. I did not realize that there were any wires to be concerned with. Where are they located and what do I need to do with them?
Also, is it really necessary to replace the intake port gaskets if they are not damaged or swollen?
Thanks for your help.

 

Thank you!!! I will use motor oil.

 

Most of my beverages come in brown glass bottles, and I use paper plates Ahhhh.... bachelor life!

 

Yes, I have done this swap a few years ago to my '99. Very easy really.
I would also recommend cleaning (vacuum) all the sand, dirt, grit, etc from around the periphery of your old manifold that you can, before removing it. Helps keep any of that stuff from dropping into your intake ports on the cylinder heads. Also, after removing your last bolts (the rear two may not come up all the way and some tape wrapped around them will hold them up) move the manifold forward a few inches and look at the backside. You'll see a small (1/8") black nylon vacuum line attached to the rear on the manifold. Make note of where it goes. It is very short so that's the best time to unplug it. Make SURE to re-connect when installing the new manifold or your A/C will not function properly.
As far as gaskets go, take a good look at your old ones. If they are in good shape with no tears, rips, etc then you can re-use them. Maybe just compare them with the gaskets on the new manifold (assuming they are present) and use the best of the two. They are a pre-molded silicone type and are pretty durable unless abused.
The wires I mentioned will be apparent after the old manifold is off. They are for the two engine knock sensors and run from the rear of the engine forward to each of the two large rubber grommets. Just remove and discard the two green plastic clips you'll see as the new manifold extends down much further and cause some interference.
Everything is pretty straightforward. Oh yeah, be sure to clean the manifold bolt threads of any old threadlocker and use some Loc-Tite blue (a drop or two is fine) and BE SURE TO TORQUE THEM DOWN TO THE PROPER TORQUE. They are very slender and long and can be very easily over-torqued. I'm at work and don't have the torque spec handy right. Maybe someone else can help here.
HTH,
Robert

 

Robert,
Thanks again for sharing your knowledge. I can get the torque specs. I have the GM manual on cd. There's nothing like practical experience to make the job easier for another guy!
I can't wait to get started. I am going to clean out the new (used) intake tomorrow and install it on Saturday.
Bob