Question : Intake Manifold Gaskets

[austinr1999]

It's time to replace my lower intake gaskets on my 2001 Malibu. I was wondering if anyone has advise on gasket brands? I am thinking of going with "Victor Reinz" from Rockauto. I've read that they don't require sealant. Also is there a real need to replace the bolts if I use loctite? I'd appreciate any advise from folks that has been there before.

[SappySE107]

I have never had a problem with any brand of the metal/rubber gaskets. None of them require or recommend silicone other than the valley, which is required for all of them. New bolts are not required if you clean the threads and add loctite.

[austinr1999]

Thanks, I read someone's post on another site. They recommended a continuous bead of black rtv silicone. Never been inside a 3.1 before so I wasn't sure.

[austinr1999]

Ok I finally gathered my parts and got started. I have everything off down to the plenum. Now I have another question...Would there be a problem if I unbolted the EGR valve from the pipe and left it attached to the plenum?

Edt: Never mind I got at the EGR bolts, as my Dad used to say "I wasn't holdin' my mouth right"

[TGP37]

You have to remove the P/S pump too. But you can get a long neck socket to the bolts through the pulley. Don't need to disconnect the P/S lines or pulley, just remove and hang with wire from the hood. Or gently set aside if your lines bend enough.

You have to remove the fuel rail, but you "can" keep it intact and remove the rail with the injectors intact. again hang from hood.

To remove the LIM gaskets, the pushrods need removed. DO NOT mix them up at all. Keep them in order and dont mix up/down sides either. Same with the rockers, keep in order.

When pulling the rockers, the pushrods can stick then fall.

Be sure to torque the bolts properly for the LIM and the Plenum specifically. Otherwise they will crack and/or ruin gasket seal.

Good luck

[bob442]

IMPOTANT:

http://wot-tech.com/shop/articles/ported-manifold-torque-specs/cat_105.html

you can/could pry the rockers up with a pry stick, or get the tool so you dont have to tourqe your rocker bolts, which is very important to do properly aswell:
Valve Rocker Arm Bolt 19 N·m + 30°/14 lb ft+ 30°
and where the lower edge of the gasket meets the valley, put a dab of silicone on the under side of the LIMG, this would be that little corner where the head meets the valley aswell. I currently have a 3100 apart if you need some pictures.

[TGP37]

When torquing rockers to a specific torque, be sure to rotate the engine at the crank pulley (with a 1/2"? or 15mm? socket).

If the camshaft nod is in position to lift the valve, the torque needed to properly bolt will be increased. As it resists the spring loading. Not too hard, just gotta stop and rotate the crank once or twice.

Whether it makes a difference, the springs load, on a pushrod...idk.

I just bolt the suckers down tight then top off with the torque wrench at 35 lb ft + 30°.


Just don't install the rockers with any dirt where it pivots. I cleaned then added assembly lube. An old beater you could just reinstall.

Is also a good time to check and make sure the pushrods aren't bent and/or clogged up. If you find any oil coking, check the pushrods as they are like straws.

[austinr1999]

Thank you to everyone for the great advise. I have the manifold off and doing cleanup. It's little wonder it was leaking the bolts on the ends were so loose I could have taken them out with my fingers. How clean do I have to get the surfaces? I have them as clean as I dare without scratching them up. Still have some discoloration but feels smooth to the touch. Thank you again.


Update: Thanks for the torque specs, my Haynes manual said to finish off at 187 ft lbs + 30°. That sounded sort of high for rocker arms.

[bob442]

That sounds like the main caps. Or inch pounds
Anyways, you need to clean down where the silicone is applied to the metal, and it's a good idea to wipe the gasket surfaces with alcohol to prevent any contamination swelling or cracking of the new gaskets, it may sound like overkill, and I'm sure everyone will say they have done it a hundred times with out this step. What gaskets are you using? Hopefully the steel felpros. And dont forget to torque the upper intake carefully too, I've cracked a upper intake myself once. Not a great feeling on a Sunday afternoon.



Sent from my iPhone using my iPhone at work cuz I have nothing to do

[TGP37]

Bob is right. That advise really means a lot for longetivity of the seal. You could "not do that" and still have a seal, but it could leak much sooner then it has to.

Remember, when you lift the LIM off the engine, coolant dumps into the crankcase. Before you turn the engine over, open the oil drain and let the excess water pour out. Since oil is lighter, the water will come out first. So it only takes a moment opened. Otherwise, drain and replace the oil.

[austinr1999]

Bob, I'm using Dorman metal gaskets. They sure feel much more substantial than the plastic gaskets that were on it. Thanks for the advise on cleaning I already have the gaskets on but I cleaned the surfaces very well. I will clean the intake surfaces with alcohol. I would have liked to have shined them up with a wire wheel but I knew better LOL. Thanks for the heads up on torquing the upper intake, I'll be very careful.

[TGP37]

Never use power tools on a surface that requires a gasket, lol.

I prefer to use a soft scrubby with brake cleaner and a razor for the tough spots. I have used thin layers of RTV to enhance a gasket seal I may question.

Or if you notice a small scratch/gouge in the metal, use RTV to seal it.

[pocket-rocket]

I use razor blades almost parallel with gasket surfaces for stubborn gaskets. If I have the part off and really want to make it nice and clean, it's #0000 super fine steel wool. I know it's steel, but it doesn't damage the surface. It brings it back to a new like shine. I use brake clean on a shop towel, not alcohol, but either should be fine.

The only power tools I would use on gasket surfaces on aluminum would be those 3M pads in a die grinder on low pressure, for sure not a wire wheel.

[austinr1999]

Thanks guys, I used a razor myself and got the surfaces as clean as possible. Yes I knew a wire wheel would have torn things up pretty bad, if I ever have to do another job like this I will remember the tip about steel wool.

[3400-95-Modified]

187 pound inch = 15.583 pound foot

if you were wondering.

That matches close to what Bob said