'02 Impala (3.4l): Intake Manifold Gasket Replacement Q's


About to begin the intake manifold job on my '02 3.4l Impala (93k). Picked up the Felpro gaskets a few weeks ago. Mechanics will probably think this is crazy, but I went through my shops manuals and expanded the entire removal and install (sub) procedures into one big linear procedure (so that I can procede from step A to Z without flipping pages back and forth in my manuals).

Got a few questions after doing this, however:

REMOVAL STEP #2: Remove the Upper Intake Manifold:

1.) Sub-Step 10 says to “remove the ignition coil bracket with the coils”, however the sub-steps say to remove the coils from the ICM. Will this be necessary?

2.) Sub-Step 13 says to remove the EGR valve, which has a gasket. Will this gasket need to be replace on re-install?

3.) Sub-Step 18 says to remove the throttle body if replacing the intake manifold. This implies that I shouldn’t have to remove the throttle body, right?

4.) Sub-Step 19 says to “clean the upper intake gasket mating surfaces”. How is this best done?

REMOVAL STEP #3: Remove the LEFT valve rocker arm cover:

5.) Sub-Step 3 says to “remove the right engine mount strut”. Sub-Step 4 says to remove the thermostat bypass hose and pipe - which includes removal of the “LH engine mount strut”. If BOTH engine mounts are removed, what’s holding up the engine at this point? Also part of the T-stat bypass hose/pipe removal is the removal of the “fuel injector sight shield”. Can all this T-stat bypass hose/pipe removal-related stuff be skipped? I thought I remember seeing someone say they did this.

REMOVAL STEP #9: Remove the fuel FEED pipe from the fuel injector rail:

6.) Sub-Step 1 says to “Relieve Fuel Pressure” by installing a fuel pressure gauge fitting and fuel pressure gauge, then installing a bleed hose and opening a valve. What’s the easier way to do this?

7.) Sub-Step 5 says to “Disconnect the quick-connect fittings from the fuel FEED pipe and the fuel return pipe in the engine compartment”. Sub-Step 6 says to “Disconnect the quick-connect fitting from the fuel RETURN pipe in front of the fuel tank”. Is this necessary?

REMOVAL STEP #11: Remove the Fuel Injector Rail:

8.) Sub-Step 14 says to “Remove the injector O-ring seal from the spray tip end of each injector”. Is this necessary?

REMOVAL STEP #12: Remove the power steering pump:

8.) Do the pressure line and return hoses need to be dis-connected? Can I avoid bleeding the system later on?


INSTALL STEP #5: Apply bead of RTV Sealer (to install Lower Intake gaskets)

9.) What type and brand of RTV Sealer should I use (other than the GM P/N mentioned)?

INSTALL STEP #7: Install the valve rocker arms and push rods:

10.) Sub-steps specify “pre-lube” to be put on the ends of the push rods and rocker arm friction surfaces. What type and brand to use ?? Also when the valve rocker arm bolts are tightened to 19 N-m, it also specifies an “additional 30 degrees” of tightening. What’s with that?

INSTALL STEP #9: Apply thread locker to lower intake manifold bolts:

11.) Can I buy the thread locker in a store, or do I have to get the GM P/N? Also, can I clean and re-use the old bolts?

INSTALL STEP #10: Lower Intake bolt tightening schedule:

a.) Tighten the vertical lower intake manifold bolts (4 inner bolts) to 7 N-m or 62 lb in

b.) Tighten the diagonal lower intake manifold bolts (4 outer bolts) to 7 N-m or 62 lb in

c.) Tighten the vertical lower intake manifold bolts (2nd round) to 13 N-m or 115 lb in

d.) Tighten the diagonal lower intake manifold bolts (2nd round) to 13 N-m or 115 lb in

Are this values still good, or have they been revised since the manual was printed?

INSTALL STEP #15: Install the fuel injector rail:

12.) Sub-step 8 calls for NEW O-RINGS in the fuel feed pipe and fuel return pipe. Necessary?

INSTALL STEP #24: Install the upper intake manifold:

13.) Sub-procedure makes no mention of any sealant being used on the gaskets. Is this correct?


Also, procedure doesn’t appear to mention any special tools. Are there any, or are there any ADDITIONAL repairs that are recommended that the manual hasn’t mentioned?

Sorry for the length of this post…


here is a http://www.naioa.com/v2/modules.php?name=Forums&file=viewtopic&t=3354 Impala club, I bet someone over there may be able to answer your questions. I linked you directly to the Intake Manifold Sticky, Keep us informed
Good Luck


These responses are numbered corresponding to the numbering in your post, which I’m sure you noticed.

1: You may leave the coils connected to the ICM if you’re removing the whole ICM. Be sure to disconnect the negative battery terminal before beginning the operations.

2: Yes! Number one rule of gaskets: Always Replace Gaskets with NEW Gaskets when Gaskets are Removed!!! Remember that, it’s a never changing rule.

3: You’re not replacing the manifold are you? It only says that because you’d be changing the throttle body to the new manifold.

4: Use a gasket scraper but only one MADE OF COPPER!!! That’s 150% important because many intake manifolds are made of aluminum, which is very soft. A steel scraper will be very likely to nick and gouge. A gasket removing solvent can help. Don’t use gasoline it’s a messy ordeal trust me.

  1. I think you’ll be okay just removing the hose. Which you should be able to do no prob. However, the sight sheild is just the cover that says something like “V6” or “3400” or “3.4L” or “MPFI” or something on it, right?

  2. Find the test port on the fuel rail, remove the cover. Wrap a rag around the rail or place it underneath the rail. Drape a second rag over your hand. You’ll be using a pen, or some other item that can poke into a valve, to poke the valve and open it. That’s why the rag is draped over your hand, to block fuel spray. Place your hand over the valve so that the rag drapes over the valve and your hand, turn your head as far as possible in the other direction and close your eyes, and poke the valve, the fuel will squirt. (Actually you can probably just poke the valve without all the other bogus but for cover-my-@$$ purposes I had to give you the safer method first!)

  3. Don’t see why you would need to disconnect the pipe at the tank except to let the fuel in the line drain out. Find out and see.

  4. Yes. You will be replacing these O-rings before reinstallation. Number 1 rule of O-rings is the same as number 1 rule of gaskets. Plus, you have the opportunity now. How would you feel if you had to do this all again if one failed later? See the logic? =)

8 (again). FYI, you double numbered your numbers. But I’m sticking with them. This is your SECOND number 8.
You can try hanging the pump out of the way with the lines still attached. You will have to try and see for this one. Bleeding a power steering system is easy, mainly just turning the wheel. Just don’t forget to fill the reserviour before starting the proceedure; yeah I did that once…oops!

  1. Permatex RTV Silicone. Blue will work, black will work, Ultra Copper is the best of the best because it’s indestructable AND to boot, you can use it to make your EGR valve gasket. Yep! You can make that gasket out of this stuff. However I still RECCOMEND using both a gakset and RTV. They work best as a pair.

  2. Pre-lube is probably moly-base assembly lube. The whole “additional 30?” is just a testament to how precise some things in modern engines are. During a rebuild, you’ll see that kind of torque figuring OVER and OVER again. Don’t worry about WHY it is, just follow it. Once the click-type clicks at 19n-m, turn the ratchet another 30? and consider it torqued.

  3. Due to the torque figures on some of these bolts, and their small sizes, I’d suggest replacing them. Anyone would. And if the book says use new ones, well then there’s your answer. And yes, you can buy the threadlocker at any auto parts store. RED is the kick@$$ stuff. It actually warns you on the package that if you use it, you will need special tools to remove that bolt. RED is also OEM spec. Different colors correspond to different strength and temperature ratings. So you will have to make a pick.

Seems as if you need a shopping list!

Also, for that ABCD business, those figures are fine.

  1. Absolutely. Remember the number one rule. Matter of fact, we’re gonna call it the GOLDEN RULE!

  2. Not all gaskets need sealant. Some are really tight and therefore sealant could leak out of the gasket mating surface and into the intake manifold or whatever the gasket was sealing. Use it where suggested.

Finally, follow the manual as much as possible, but also use your instincts and your judgement. By-the-book just isn’t 100% feasable, ever. Sometimes you have to do things how you feel. Be sure to set aside a full weekend and have a backup car. You will almost certainly need to take one or two trips to the auto parts store. It happens. It doesn’t mean you’re a bad mechanic, matter of fact, it probably shows the opposite! =D




Thanks, I’ll give it a shot over there, too to see if anybody has anything else to add.

Big Riviera:

Whoa! That’s a detailed answer - and I LOVE detail (as long as it’s pertinent and informative)! Oh, and sorry about the double #8. I’m surprised I missed that. I’m usually very careful in most everything I do (probably TOO careful a lot of the time).

So let’s see, I need to pickup:

1.) EGR gasket
2.) COPPER gasket scraper (easier on aluminum parts)
3.) Gasket remover solvent (maybe)
4.) Injector O-ring seals (6).
5.) Fuel feed pipe and Fuel return pipe O-ring seals.
6.) Permatex RTV Silicone (blue,black, **Ultra Copper)
7.) Moly-based assembly lube (pre-lube push rods)
8.) New bolts with threadlocker from GM.

Probably shouldn’t mess with the threadlocker strengths. Might use one too strong or too weak…

Thanks Matt!


I have an Impala 2002 which needed the intake manifold gasket replaced. Briefly, Disconnect battery, removed the alternator along with serpentine belt, EGR and reused the gasket, unbolted the power steering box and moved it out of the way to get at the diagonal both for the plenum. The ignition coil has to be removed and while you?re at it remove the driver side ignition coil stem that the coil nut is attached to later remove the valve cover bolt on the driver side. The throttle body needs to be removed and the carburetor can be left on. I disconnect the fuel line with a $5 disconnect tool from AutoZone. Place a rag under the lines to catch the fuel. I removed the fuel rail and left all injectors in place and sprayed around the o-ring and the bottom of the injectors with wd-40 to clean them and before installing I used clean 5w 30 motor oil to lube up the rings. I removed all wire connections after I marked all wires with masking tape as to what they attached to, the throttle cables need to be disconnected along with the upper radiator hose. I then removed upper plenum, fuel rail with gasket, then removed lower intake manifold using small pry bar which to my surprise came off easily. I made sure I had small boxes with holes to place all bolts in sequence they came out. I then loosened the push-rod rocker arms to remove rods and make sure you place these in the hole of the box in the sequence they came out due to different size rods. I sprayed the holes of the rods with oil. Incidentally, I found the diagonal bolts on the lower manifold to be loose. I then removed the gasket and used acetone to clean all surfaces where the upper and lower gasket sits. I have 139,000 miles on my car so I replaced the water pump. Then reassembled in reverse order of dismantle. I purchased replacement gasket and gasket sealer from my local Chevy dealership. After everything was put back together I waited overnight to let the gasket sealer harden then started my car when I noticed the temperature was running hot. To make a long story short the new thermostat was defective and I dug my old thermostat out of the trash and used this instead of buying a new one and the car is running great. The throttle body and carburetor had to be removed to get at the thermostat so it might be a good idea to do a boil test on your new thermostat vs. the old one when you have things apart to make sure the new one opens like the old one. My boil test revealed that the old stat opened in 14 sec and the new stat took 55 sec and did not fully open. Hope this helps you.


If you want to save some gasket scraping time, buy a can of aerosol gasket remover.
Spray on, let it foam up and work for about 10 minutes, and you can pretty much wipe a lot of that old material off with a rag and a single edge razor blade.

Word of caution. If you use this stuff, do not EVEN get it on your skin or eyes. Avoid the wind and spray carefully.
Get it on you and you’ll be running for the nearest lake in about 5 minutes.


1.) It is not neccesary to remove the coils from the ICM however, it will be required to remove the rear ICM mounting stud to access the rear valve cover bolt.

2.) The gasket kit should include a new gasket for this and it should be used.

3.) It is only neccessary to remove the throttle body from the upper intake if you are changing the upper intake.
4.) I have found that an aresol gasket remover and plastic scraper worker best. Be careful not to get the gasket remover on your skin or in your eyes (Sounds like OK4450 and I have experienced this for you it is not fun.)

REMOVAL STEP #3: Remove the LEFT valve rocker arm cover:

5.) These are strut mounts they only keep the motor from rolling fore and aft. There are still mounts holding the motor and trans to the sub frame.This step can be eliminated but requires extreme caution to avoid damaging the components (removing them is best.)

REMOVAL STEP #9: Remove the fuel FEED pipe from the fuel injector rail:

6.) Depress the shrader valve with a ball point pin. Wrap a rag around it to catch the fuel spray.
7.) Disconect the fuel lines at the fuel rail ONLY!

REMOVAL STEP #11: Remove the Fuel Injector Rail:

8.) The gasket kit should contain new injector o-rings so yes. Place a small amount of mineral oil on the new o-rings for easier instalation.

REMOVAL STEP #12: Remove the power steering pump:

8.) Once the P.S. pump is unbolted and the line retainer on the back of the alternator is removed you can lift the assymbly up and swing it out of the way.

INSTALL STEP #5: Apply bead of RTV Sealer (to install Lower Intake gaskets)

9.) There should be a tube of aluma seal in the kit.

INSTALL STEP #7: Install the valve rocker arms and push rods:

10.) Any assembly lube will work fine. The additional 30 degrees is typical of GM torque sequence.

INSTALL STEP #9: Apply thread locker to lower intake manifold bolts:

11.) Any over the counter (blue) thread locker will work.

INSTALL STEP #10: Lower Intake bolt tightening schedule.

INSTALL STEP #15: Install the fuel injector rail:

12.) Yes, they should also be in the gasket kit.

INSTALL STEP #24: Install the upper intake manifold:

13.) This is correct do not use sealant here. Some felpro gasket tack may be used to hold it in place for installation.

Also, procedure doesn’t appear to mention any special tools. Are there any, or are there any ADDITIONAL repairs that are recommended that the manual hasn’t mentioned?
You will need a fuel line disconnect tool if you don’t have one.
Remeber to keep push rods and rockers in order for re-installation.
Fresh antifreeze, new thermostat, and fresh oil are a must.
Take your time and ask any questions that arise. Tester, OK4450, and others will help and they know what they are doing.