INTAKE GASKET MAIN PAGE, PLEASE POST Q'S&A'S HERE!

[cdru]

Since links come and go but hopefully posts last forever, here is the text of that link:

Intake Manifold Gasket – How to

This was done on a 2000 Chevy Venture. Should be very similar on 97-99 models of Venture and Montanas.

This is a big job. I think a shop would do it in 6 to 8 hours but I would estimate for first time backyarders to allow 14 to 18 hours depending on whether you do other stuff while in there. I cleaned injectors, did spark plugs, wires and this took extra time. You have to take off a lot of stuff to get to the gasket!!

The new redesigned gasket kit (part number 89017279) comes with 2 lower intake gaskets and 2 upper intake (Plenum) gaskets and costs about $100 Canadian including taxes. You should also get 2 new valve cover gaskets. (It can be done by removing just one cover, although I removed both), bypass coolant pipe o-ring, oil drive pump o-ring, fuel rail o-ring.

Here are the steps I went through. Obviously some can be done in different order. This is not meant to be gospel, just thought it might help someone else.

1. Remove passenger side fender support (3 bolts), and fuse box (1 bolt) to get access to the negative terminal of the battery. Using 8mm socket remove the negative terminal and move away so it doesn’t re-connect.
2. Relieve the fuel pressure by opening the gas tank cover and by unscrewing the cap on the end of the fuel rail (located behind power steering reservoir). I used a small length of plastic tubing (4 inches) over the nipple on the rail and a screw driver through the hose to depress the valve (looks like a tire valve). Catch the gas coming out of the hose with a dish (only couple ounces).
3. Remove the throttle cable and cruise control cables from the throttle body. Use pliers to squeeze the plastic clips holding the cables to the brackets.
4. Remove the rubber flexible duct between the throttle body and the air breather. Remove the connectors (label) and pipe running to rear valve cover. Loosen the hose clamps and twist it off carefully. It is difficult to get off and twice as difficult to get back on. Get some silicone grease to put it back on with!!!!!
5. Loosen the wiper arms nuts (8mm) (left one and middle one), disconnect and swing the arms out of the way.
6. Disconnect the wires and connectors running from the plenum. Label each wire and connector so you know where to hook back up. Do the wires connected to the throttle body also. Don’t need to disconnect the spark plug wires … yet.
7. Disconnect 2 wire plugs from the Throttle Position Sensor (located behind throttle body). There is a third small pipe connection that I left in place. Unbolt the TPS and route it out of the way.
8. Rotate the engine forward. Remove the passenger side mount (4 bolts on rad support) and the bolt closest to engine. Get a ratchet strap or cable and hook to engine lift on drivers side and to rad support or down under frame. I used cable pulls and hooked underneath to the frame. Put some rags to avoid scratching bumper. You don’t need a lot of torque, so you could probably get someone to pull the engine forward and tie if off with rope. Of course, once you a little tension on your cable, undo the driver’s side mount nearest the engine and ratchet the engine forward. It makes it easier to get to the stuff at the back of the engine.
9. Remove ignition coil. Remove plug wires from ignition coils and label them if they don’t already have numbers on them. The sequence to the coils is 5,2,3,6,4,1 from left to right. Remove wire connectors on coil, 1 on left side , 2 on right. Unbolt the coil … 2 bolts easily reachable in the front and 2 nuts way down behind the coils (use a long extension on the ratchet).
10. Remove MAP sensor. It is located directly in front of ignition coils. Two 7mm bolts. There is a small hose connected to plenum and a wire plug to remove once it is unbolted. (Remember, label all wires).
11. Remove serpentine drive belt. This can be done by loosening the bolt holding the tensioner, or pulling the tensioner forward enough to slide the belt off the forward idler pulley. It is tricky getting this back on also. I didn’t have a tool to fit the bottom of the tensioner to pull it forward so I had to use left hand to pull on tensioner while using right hand to slide belt on idler pulley … it’s tough.
12. Remove alternator and bracket. This I found difficult and I think it is different on 97 to 99 models. There are 2 bolts at the back of the alternator and one on the side. Loosen the one at the side first (The one at the side bolts to a bracket bolted to one of the bolts for the upper plenum.). The left bolt at the back is hard to get at but the right one isn’t bad. Remove bolts and the wire on top of the alternator as well as the wire plug on the rear. The alternator can either be removed (tight fit) or positioned out of the way. Next, the bracket the alternator was bolted to needs to be removed. 3 bolts in this … 2 on the side (15mm) where the serpentine belt runs and one at the back. It also holds the engine lift bracket.
13. Remove EGR valve. This is located to the right of the map sensor and behind the throttle body. The trans dip stick bolts to it. Remove dip stick nut first and then 2 nuts holding EGR valve. Careful with the gasket between the EGR and the Plenum, It can be re-used if not damaged.
14. Remove any other connections to the upper Plenum. There should be a vacuum line on the rear passenger side and a hose next to that.
15. Remove the upper plenum. First remove the 2 water hose clamps under the throttle body connected to the bypass pipe (black). Then the nut holding the bypass pipe to the throttle body (under throttle body). Plenum has 6 bolts with torque sequence: 5,2,3 left to right at the back and 6,1,4 left to right on the front. So the first bolt to loosen is the middle bolt nearest you (number 1), then the one at the back, etc. Bolt 5 has the alternator bracket attached, bolt 2 has the map sensor bracket, bolt 4 has the spark plug wire harness connector, bolts 1 and 6 have a bracket for the main wire harness.
16. Have a drink of water and a rest.
17. Remove the injector wire plugs. Label if not already labelled. Wires are 1,3,5 on back, left to right and 2,4,6 on front. Move the wire harness out of way. Take special note of the wire harness here. Note that a wire runs to the thermostat housing and one runs around near the Oil Filler cap for the Camshaft Position sensor. When putting back the harness make sure you don’t forget this wire and how it’s routed.
18. Remove fuel lines into fuel rack. Do not remove the fuel rack and injectors (unless you plan to clean the injectors … get new o-rings if you do). You can get to the lower intake bolts with this in place. There is a small bracket holding the fuel lines in place. Remove this first. The fuel line connected to the rail farthest from you has an o-ring that should be replaced or at least don’t lose it when pulling the line out. When loosening the connections, use two wrenches so you don’t put unnecessary strain on the fuel rack. The connection closest to you is removed from the bottom of the fuel pressure regulator.
19. Drain Cooling System. The plug is plastic on driver’s side and turns quarter turn then pulls out. Open the bleeders also. One on top near thermostat housing and one on passenger side on bypass pipe.
20. Remove pipe from back of thermostat housing to flex hose. This pipe has a bracket holding it. Once bracket is removed, the pipe pulls straight out. It has an o-ring on it.
21. Disconnect bypass pipe at passenger side. Has one 8mm bolt holding it. Pulls straight up and has o-ring on it (to be replaced).
22. Loosen power steering pump and move aside. Three bolts accessed through the holes in the pulley. Don’t disconnect the lines. The lines are clipped to the frame by plastic catches. Pull them out of the clips and this give room to move pump aside.
23. Valve covers. Remove the front valve cover. Four bolts that stay with the pan. There is some RTV sealant holding 2 upper corners of the gasket. The rear cover is the same. I’ve been told that you can get away without removing the rear cover, just the top two bolts; however, it will be easier if it is removed.
24. Check for any wires or connections that may have been missed and disconnect and label. There is a heater hose near the bypass pipe you may not have removed yet.
25. Loosen Intake bolts. There are 4 upper vertical bolts and 4 lower bolts. The lower ones are harder to get at but you will probably find they are loose anyway.
26. Remove the lower intake. There may be a bit of coolant spill as it being removed. Now you can see the damage.
27. Loosen the valve lifters enough to remove the push rods. The rods are different lengths so make sure you keep track of where they come from (make a box to stick them in).
28. Remove the old gasket. Clean the mounting surface as clean as possible using a scrapper and solvent. It’s usually not that bad but a little harder where the RTV sealant was used.
29. Now is the time to do the oil pump drive shaft o-ring (round shape). It is one bolt that would have been under the thermostat housing. The shaft pulls straight out. Replace the o-ring and put back. (Not required but nice and easy to do)
30. Good idea to clean the bolts and tap the threads before re-installing. Place the new gaskets in place. Replace the push rods in the order you removed them and tighten the lifter bolts. Place a bead of RTV sealant (about ¼ inch) on the ridges between the heads.
31. Place the lower intake carefully and hand start all bolts after using some blue thread locker on the bottom 3 or 4 threads. The torque for the bolts has changed and is included with the new gasket kit. The sequence is to tighten the 4 upper bolts first. Sequence 4, 2 left to right on back and 3, 1 closest to you. So first bolt is on driver’s side closest to you. Then do lower bolts in same sequence.
32. Install the rest of the components in reverse order.
33. Change the engine oil and filter.
34. Add coolant or water to start with. Remember the bleeder screws when filling. Watch temp gauge when first starting to ensure not air locked.


Things to watch for:

a. The wiring harness for the injectors. Take special note.
b. The torque for upper manifold (Plenum) is 18ft lbs. I think that is too much (or my torque wrench is bad). Back off a bit and use thread locker … remember its aluminium.
c. You may have to pry one corner of the fuel rail up when putting the power steering pump back to get enough room around the fuel pressure relief valve. Watch the o-rings on the injector.
d. The rear sparkplug wires run very close to the very hot EGR pipe. I found out the hard way to take special care when replacing the wires and the bracket holding them that bolts to the Ignition coils.

[85lolo]

OK my wifes 99 venture, with 103000 mi. recently began forming a puddle dead center of the front of the engine. I went to her work just now and looked after van sat for 3 hrs and the puddle is as big as a foot or more across! is this to rapid of a leak to be the lower intake???

[85lolo]

she came home for lunch, I went out to top off the coolant, and tried to see if I could find the source of the leak, ( sucks because it is dripping with snow melt and slop) the only thing I found was a fitting where the upper hose connects to the engine. it has a wire plug to it, is this the coolant sensor?
It is all wet around the fitting. I hope this is my problem
I am going out now to check the oil for the infamous white milky stuff

[Huney1]

Old info

[hufhouse]

Originally Posted by Huney1

Two diferent things entirely because milky stuff on the oil cap is indicative of a blown head gakset where coolant gets into the lubrication system, or oil.

Wait! I thought that the leaking lower intake manifold gasket causes coolant to get into the oil. That's why you get that caramel stuff on the oil cap and PCV valve.

[cdru]

Originally Posted by hufhouse

Wait! I thought that the leaking lower intake manifold gasket causes coolant to get into the oil. That's why you get that caramel stuff on the oil cap and PCV valve.

Both can cause it.

The sensor at the upper radiator hose is the coolant temp sensor. There is also the thermostat there that has a rubber gasket that could have broke as well.

A leak that much in that short of period of time doesn't seem like an intake leak. It's almost too much. I'd be suspect of other issues like a leaking hose or hose clamp, but I'm not saying it can't be the intake gasket.

And the radiator cap is either 15 or 16psi, not 17 (at least it's that way on my 98). It is stamped on the top of the factory radiator cap.

[hufhouse]

Just finished this job, and I wanted to add some hints from my experience.

1. Take a few digital pictures before you start. Mostly to figure out how to route the wiring and vacuum tubes when you finish.

2. You can't label things too much.

3. You'll never have a better time to change the plugs and wires.

4. On my 2000 Montana, the tensioner pulley is also a bolt for the alternator bracket. That cost me about an hour.

5. This job is do-able for you if you have basic mechanical ability. The peak of my prior mechanic experience was changing brakes.

6. This job will take a long time. I don't know how GM mechanics can do this in 6.6 hours, or whatever GM says. This is MORE than a weekend job, especially if you do plugs and wires and stuff, too. Be patient.

7. Getting the EGR valve back on was probably the hardest part for me. I had a lot of trouble lining up the bolts and gasket in the very limited area. Very frustrating. Be prepared. Just take your time and you'll eventually get it.

8. You will need a 10mm crow's foot. I didn't know what a crow's foot was when I started. Now I do.

9. When the van started up, it was one of the most gratifying and rewarding jobs I've done. I'm glad I tried to do it myself. I had my doubts a few times, but now that it's over, I'm glad I did it. I learned A TON.

10. I would strongly suggest getting a small set of taps. The white stuff that GM uses on bolts is like drywall mud or something. Especially on the intake manifold bolt holes, it would have been nice to "ream them out" before reassembling everything.

That's all I can think of right now. Don't be afraid of this job. VERY time-consuming, but with the info from this board and a Haynes Manual, I think just about anybody could pull it off.

[85lolo]

well the rag was not wet at all, and there was no new drips on the floor,
sooo, since there is no sign of stuff in the oil Ill wait and watch closely and Ill be back if I got questions
thanx guys

[Huney1]

Originally Posted by 85lolo

well the rag was not wet at all, and there was no new drips on the floor, sooo, since there is no sign of stuff in the oil Ill wait and watch closely and Ill be back if I got questions thanx guys

Hmmm . . . . Intermitten leak huh? Make sure the coolant reservior white plastic tank is filled to the proper level and keep an eye on it and unless you have a leak the level should stay fairly constant with no big drops or losses. If you get another puddle abrorb it with a rag and smell it and DexCool has a very distinct urine odor. Seriously, when I flushed mine it stunk like an outhouse and if you can catch it in a bowl it's pink.

About radiator caps. Important to replace it when it gets a ridge mashed into it or about every two years. I use a 13 lb summer cap and 7 1b winter cap.I live way down South and that should be all I need.

[Huney1]

If I was still a young whipper-snapper I'd tackle it in a skinny minute, but now that I've reached the "golden years", no way.

[cdru]

Originally Posted by hufhouse

6. This job will take a long time. I don't know how GM mechanics can do this in 6.6 hours, or whatever GM says. This is MORE than a weekend job, especially if you do plugs and wires and stuff, too. Be patient.

It gets easier the more you do. I've done mine 3 times. First time I used the old gasket style (I hadn't found here yet), which required the 2nd time 6 months later. The 3rd time was a week after the 2nd when my head gasket went. I don't think I could have the whole thing done in 6 hours, but I bet if I really had to I could.

Having the right tools, knowing where the "short cuts" are, and labeling everything is key to doing a good job in the least amount of time. If you have to stop and figure out whether the long push rods are for the intake or exhaust valves eats up a lot of times.

Whenever I work on a vehicle now, I always have a box of snack-sized and sandwich-sized ziploc baggies and a permanent marker. It's quick and easy to label the bag, toss the nuts/bolts/brackets in them, zip em up and toss them aside.

[85lolo]

well I changed the oil tonight it didnt seem over full but the oil looked more like chocolate than oil, and the whole driver side of the enging and transaxle is dripping with antifreeze.
can there be such a thing as an external and internal leak??
I didnt spend much time looking for the source cause it is right at 0 degrese out and it was enough to just change the oil

[cdru]

Yes you can have both an internal and external leak.

[GMCritic]

Originally Posted by 85lolo

well I changed the oil tonight it didnt seem over full but the oil looked more like chocolate than oil, and the whole driver side of the enging and transaxle is dripping with antifreeze.
can there be such a thing as an external and internal leak??
I didnt spend much time looking for the source cause it is right at 0 degrese out and it was enough to just change the oil

You should get that fixed ASAP before it damages your motor... Sorry to hear of your problems. The fix can run anywhere from $500.00 to $1000.00 depending on who does it.... then again, you can try to fix it yourself, but then you have no guarantees when it's finished.

Take care.

[85lolo]

I think I might puss out on this repair, I think I could do it but I dont have a heated garage and this is feb. in Iowa , and Im just not confedent enough for the electrical computer crap
Ive got an 85 monte carlo that I dont hesitate to tear it down to nothing and back. the new stuff is a little scary to me