How do you replace a lower intake manifold gasket on a 1999 Chevy Malibu?

Answer 1

Just done that job last week end... I usually speak french but I will do my best to give you good advice and hints.... I found the guide on autozone (you have to register but it's free). They have all the repair guides for your vehicule so if there's something in my instructions that you don't know how to do, just go to this site and you'll find out... for exemple, if you're not sure how to remove the rockerarms, they have a section for that.. so while doing the job, having a computer near is verry helpfull.tools required:

-keys and ratchet tools that goes to 18mm. Some bolts are in close area so be sure you have short ratchet and keys...

-a jack and a 2x4 like the previous guy said

-torque wrench

-a puller to remove the Power Steering pulley

-a pair of vise grip and one of long nose (for coolant hoses)

-12 cans of coors light

!!! Be sure to buy gaskets with a metal ring on them so you'll never do this job again!!! some cheapers are only in plastic and that's why the same issue is coming back often... mine are 'victor reinz'.

you can take pictures all along the job so you'll have visual indications on how to put back everything... Be sure to tag every single bolt that you remove.

1- unplug the battery, remove coolant cap.

2- flush radiator. The plug is located on the lower right corner of the rad. On my car it was blue. !!! just make 1/4 turn !!! you might need a pair of long nose...

3- remove the coolant overflow retainer (where was the cap) and cruise control. don't unplug anything, just put these things out of the way. you can also remove the battery you'll have more room later and you'll understand why!

4- unplug everything on throttle body, air cleaner assembly and the plenum (higher intake where it's written 3100 v6) (you can tag, take pictures etc) and remove air cleaner assembly from the trottle buddy.

5- disconnect the cables on the throttle buddy and the bracket on it (3 bolts).

6- remove egr valve (2 bolts) and unplug the pipe (put if out of the way).

7- remove the power steering lines braket ont the alternator. DONT DISCONNECT ANY POWER STEERING LINE!! you will just put all these things out of the way.

8- tag and disconnect the ignition wires. Remove the ignition assembly (you can just put is out of the way without disconnecting it.

9- remove the serpentine from the alternator, (I needed to remove the tensionner). For the tentionner, use a 3/8 ratchet to remove tention. then your ratchet will be squeezed in it so with your 1/2 ratchet and a 15mm bolt, remove tensioner. then remove the alternator and braquet.

10- remove the map sensor, then the plenum (higher intake) (with the trottle body on it). for the plenum, you'll have 8 X 10mm bolts and 2 x 13mm bolts.

10- but you jack under oil pan and lift very gently. DONT LIFT THE ENTIRE CAR!!!

11- remove the motor mount located on passenger side. you need to make room to remove the power steering pulley.

12- using a puller, remove the power steering pulley, remove 3 power steering bolts and put all this out of the way.

13- disconnect the upper rad hose from the thermostat housing and remove the thermostat housing (you have to completely remove the upper bolt, but for the lower one, you can juste untight it. it will be more easy to put back after.)

14- remove the fuel lines braquet (1 nut) and the coolant pipe connected to the thermostat housing (1 nut) far under the thermostat housing (bolted on the engine). That's why I suggested you to remove the battery earlyer. Disconnect the coolant pipe from the thermostat housing.

15- put out of the way the hose located on the water pump (1 bolt)

16- remove the 2 bolts retaining the injection rail.

17- BE VERRY CARREFULL! Injectors cost about 100$ each. Without disconnecting the fuel lines, slowly remove every injector from it's hole. Use wd40 if necessary. I highly suggest you to take your time at this step. If you have difficulty, go on autozone site, use a good flashlight, even ask a mecanic for advices... be patient... once all injectors are removed, you should be able to put the entire assembly out of the way. *** some injectors might disconnect from the rail. That's not a problem. Just remove the clip and remove it after the rail will be out of the way. You will put it back on the rail after.

18- INSPECT your injectors!! They should all have a green o-ring and a black o-ring. If there is one missing, they are on the engine holes. Using a flashlight and a pair of long nose, go get them!

18- Remove both rockerarms covers. There is one bolt that you'll probably need a key to reach.

19- remove 4 center bolts of the intake manifold. Very important: Be sure to tag them to put them back to there EXACT location. Then remove the 4 corners bolts. There are 2 bolts that I was not able to reach with my ratchet. I used a key.

20- Slowly lift the intake manifold, making sure nothing (be carrefull to the injection rail) is on the way.

21- Remove rockerarms and pushrods. There are 2 sizes of pushrods on this engine. It is VERY IMPORTANT!!! to tag them to put them back to there EXACT location. If you don't, you'll be in BIG TOUBLES!!!

22- remove the intake gasket. At this step, you'll be able to see where this peace of crap was leaking...

23- Use a scraper and remove what's left of the old gasket including RTV where the intake contact the block.

24- put the new gaskets on the engine.

25- put back the pushrods and rocker arms. Put locktight on bolts. Torque the bolts at 25 NM.

26- RTV drys very quickly. ONLY when you're ready to put back the intake manifold, put a generous bed of RTV where the intake manifold contacts the bloc. (you should have a picture included on your gaskets kit).

27- Put back the intake manifold. Put locktight on the bolts and put back the 4 center bolts. just tight them with you fingers. Then put back the 4 corners bolts. Tight with you fingers.

28- Take a torque wrench and torque at 13 NM, starting with the 4 center bolts in diagonal.

5 1 3 7

8 4 2 6

repeat a few times. Once you're done, take your 3/8 ratchet and do a 1/4 turn. There are 2 bolts where there was not enought room for my torque wrench. I've tighted them with a key, but make sure they are tight!

29- Install both rocker arms covers

30- Install battery. Install the injection rail. I recommend using new o-rings, so you'll probably don't need to remove it again in a few days because you smell gasoline under the hood. Dont forget to put back the nut on the bracket. Then put the key on and off a few times to let the fuel pump create pressure on the system. Check the rail to make sure there are no leaks. Then disconnect the battery.

31- install power steering pump and pulley.

32- install the coolant hose that you removed from the water pump.

33- Install the thermostat housing. (they recommend me to use a new thermostat, but didn't followed this advise.) connect the upper rad hose.

34- install the pipe connected to the thermostat housing and DONT FORGET THE NUT ON THE BRACKET!!! You can put some RTV to the pipe.

35- put back the alternator bracket, the tentionner, and alternator.

36- if you completely removed the serpentine, loosely install it and install motor mount. Then remove the jack.

33- put back the collant overflow retainer and cruise control.

34- using a new gasket, put back the plenum with only 3-4 bolts tighted with hands.

35- put back the map sensor.

36- put back the rest of the bolts, torque at 25 NM

37- Reinstall ignition assembly and reconnect the wires.

37- Using new gaskets, reinstall EGR valve

38- reconnect cables on the trottle boddy

39- put back the air filter assembly. Then reconnect everything that is still unplugged. Dont forget to check at the plenum there are a few things connected on this too.

----I improved answer later... Just noticed that I forgot to tell you to reinstall serpentine belt.... :) Diagram is on the guard located on the right of power steering pump when standing in front of the engine... hope noboddy tryed to start his car without the belt on! :P

40- Be sure you didn't forgotten the to close the plug on the rad. fill the cooling system. Put something like a 1/2 gallon and....

41- When you're sure everything is properly intalled, connect the battery, crank heater to MAX, keep your fingers crossed, close your eyes, and start the car. CHECK THE ENGINE TEMPERATURE!!! as soon as the coolant is entering the engine, refill. This step can take several minutes. If you see that the engine is overheating, stop the car and wait a few minutes. Then start it back. Dont be scared to hit the gas at 2500-3000RPM... there will be more pressure on the system and air will get out easily. Once you feel heat inside the car, your car should now be safe. Finish to fill the system. You should put something like 1 1/2 - 2 gallons of DEXCOOL in it. Keep the rest in the car for a week, it could be helpfull.

Be carrefull on the road! :)

I just replaced head gaskets on a 3100. As for the intake repair the only two things I did differently were removing the power steering pump assy w/o disconnecting the P/S hoses. Retaining bolts can be accessed through holes in P/S pulley. The other is I left the fuel rail and injectors attached to the intake manifold. I just disconnected the "quick disconnects" below the brake booster. Be sure to lubricate the disconnects with WD40 and twisting quick disconnects before disconnecting.