My intake manifold recently started leaking coolant & I've decided to tackle the repair myself. I consider myself a decent backyard mechanic but have never done this.

Will the instructions provided in a Haynes manual get me through the job? They're all I've ever used in the past and I haven't had any significant problems with my other cars, but I know (from experience) they sometimes skip or leave out important info and/or steps.

Could someone familiar with the process of replacing the intake manifold gasket provide me with a list of parts/gaskets I will need? Also, are there any special tools that the "average joe" might not have required?

thanks in advance!

Hap


[Modified by HapAFcop, 7:51 PM 10/24/2003]

 

-You'll go through some one your socket extensions,
- make sure you've got a good set of torx-bits
-Pull your fuel pump fuse then run the car until it stalls, you'll have to disconnect your fuel lines on the front of your intake.

It is pretty much straight forward, make sure you identify all your parts and put them in bags marked approprietly, especialy your runner to plenum bolts as there are 4 or 5 different lenghts.
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clean all surfaces extreamly well
spray some high tac on the gaskets to hold them in place and set them on the heads
use permatex 2 for the front and rear seals not the rubber ones that some times come with the kit.

 

You can do it.. :yesnod: If you get hung up ask questions here.

 

Well, since you asked. Here goes.

First, I would try to get the factory servce manual, lacking that, still doable.

Read your manual first. Then label little plastic bags(as stated above) for each major component. Order an intake manifold gasket set, Felpro, whatever. Get the best you can. Open it up and see if the intake gasket is marked left/right. Make sure any instructions or special notes are in the box. I would order the EGR crossover tube bolts from GM, all 4. The gasket set should have both gaskets for the EGR tube. Those EGR bolts can take a beating during removal. Check the condition of coolant hoses, hoses around the throttle body, etc. Order any special molded hoses before you start. Consider going through the Throttle Body while the plenum is off. Good time to remove the Idle Air Control, clean area, install new gasket. Remove coolant and air covers on the throttle body and install new gaskets. The kit from Standard Gaskets is around $7. Get a small tube of #2 permatex for the intake bolts for reinstallation. Keeps oil from wicking up. Gasket Tack is good for holding some gaskets in place. Permatex, NAPA, whatever. You will likely need a few hose clamps, take a look and consider replacing the spring type or factory screw clamps. I prefer stainless steel. Buy 2 cans of 3M Throttle Body Cleaner, NAPA, they hide it in back, about $3 a can. Good for cleaning throttle body(check throttle shaft play), intakes, and runners. Get a Couple of flexible brushes you can reach into the runners. If your intakes have been sipping oil from the lifter valley, they will be discolored and need cleaning. New belts, antifreeze, whatever is needed.

Removing parts is pretty straight forward. With open fuel lines, be sure to remove the tank's gas cap. If it builds pressure, fuel everywhere. Keep an eye out for the two small O rings on the fuel inlet and return lines. Make sure you get the right size for replacement. As far as tools, get the absolute best T40 and T45 sockets you can afford. In my opinion, if you buy the MAC or SnapOn 3/8 drive- T40 and T45 Extension, good purchase. You don't need the whole set. The T40 is a near must(inside runner bolts). This is the one that is about 4 inches long and will allow easy access to the inside runner bolts and the bolts along the bottom of the runners. They can be tough. The T45 will help on SOME of the manifold bolts. Try really hard not to cam out those fittings. Good Sears will work too. Point is, the 4 inch T40/45 helped me.

As stated above, you must measure and note every runner bolt. I believe there are 4 different lengths per side, counting the inside bolts. Also, the corner intake manifold bolts are likely longer than the middle bolts. You can replace the manifold Torx with regular bolts but some do not like changing stock hardware. I like regular bolt heads and they torque down with ease. Whatever works.

When removing the distributor, I like getting it up on No1, mark the base, mark the area around the rotor mount, like with a scratch all, when removing the distributor, note when the gear clears the cam drive. Just a feel thing. You should be able to leave the wires attached to the cap, wire it well out of the way for dropping in the manifold and not disturbing the front and back RTV. Very important. The distributor's four wire connector in the back may be a little difficult. The tach and battery wires along the drivers side of the distributor cap have different connectors, ya can't put them on wrong. I tried.

Now if you have the cash, good time for new EGR valve, IAT sensor, Engine Coolant Temp Sensor, thermostat, plugs and wires. Another $200. So tempting, everything is right there.

Write down or use masking tape to mark the location of vacuum fittings, unless of course, you know the system. If you take the time to study and trace each line, goes a long way to knowing how your car works.

After cleaning everything and ready for assembly, would drop the intake on the heads and see if anything hangs up when lowering the intake. Make sure you can maneuver this so the drop is STRAIGHT down. Remove, install gaskets and the special gasket seal on front and back. Let set for required time, install manifold. Finger tighten the corners, get a mirror, good light and check the back and front to make sure nothing was "smeared". This is important. Hate to tell you how I know this, on a Ford no less.

When reinstalling the injectors, (good time to have them bench checked-another $60)use a little clean oil for lube. The instructions may say motor oil. (WD-whatever-some guys even use antifreeze) This will help when dropping in the fuel rails to the manifold.

Oh yea, if you think the valve covers need repainting, new gaskets, really good time.

You may note some grime in the lifter valley. Lifter guide plates really like holding the gunk. Clean the area with some rags, best to place some rags or tape the intakes closed. When cleaning is completed, remove rags/tape and VACUUM the intake ports. If you use the wife's Kirby, do it when she's gone.

Use a good torque wrench. Some people torque the inteake down to about 80% of max spec. You should have the aluminum heads If you feel the aluminum give, stop tightening, pretend nothing happened. Move on.

Well, hope everything works out. Give a shout if you have problems. Good luck with the repair.

dlmeyers 90 coupe zf6 3 speed shocks

 

Get a FelPro intake gasket set from AutoZone for around $35 or so; it has instructions as well as a small tube of black RTV to be used on the front & rear engine lands.

I also use a thin layer of black RTV around each water passage through the heads into the intake.

After scraping the front & rear engine lands of old RTV, scuff them and the mating intake base surfaces with coarse sandpaper. Then clean off all oil & debris with carb cleaner followed by a wipe with laquer thinner.

Use a thread chaser to chase the Torx bolts and holes in the heads and apply some Permatex #2 to the bolt threads.

After you apply the RTV around the heads water passages immediately lay the gaskets onto the heads. Then apply RTV around water passages on the top side of the gaskets and lay a thick bead along the front & rear engine lands. Immediately lower the intake base straight down into position. It's important to NOT move the base fore or aft once it has contacetd the RTV.

Torque the bolts to spec in three steps in the prescribed sequence. Let it stand 24hrs and retorque the bolts. Then install all other parts.

 

for the gasket (RTV) I use "the right stuff" by permtrex you can this stuff on any thing it great. use it on the gasket and the intake bolts.

 

Thanks a lot for all the replies, especially, dlmeyers. Your post is great and very detailed. You should consider posting in tech tips.

Once I get started, I'll probably be back with more questions. I'll let you all know how it turns out.

Thanks again.

 

Aside from everyones good replies already,a few tips of my own to make the job go easier.

Drain the coolant first but leave the oil.Have a shop vacuum ready and when you take the T stat housing off,use the shop vacuum to get any left over coolant out from in the T stat area.So when you pull/pry the intake off it wont spill out into the lifter valley so much.

Buy assorted vacuum caps from any parts store.You will need 2 to cap off the fuel lines when you disconnect them.Keeps gas and vapors in and stop any leaks while youre working.
Sometimes depressurizing the fuel lines dont always stop it from flowing out.

Use cardboard to make left and right side runner bolt locations and punch holes in them and each bolt that comes off,put in carboard in correct place.
That comes in handy for reinstall.Wont get them mixed up this way.

It helps to also have a wirewheel of some kind.many of the bolts will need a good cleaning and with a bench grinder equipped with a wirewheel,you can easily clean the threads off of all the bolts to make reinstall go much smoother.

You may also want to have some antiseize around.I like to use a little dab on the Runner-plenum Bolts to prevent them from seizing up over time in there.
Ive done this before and never had any bolts come loose.Of course dont use that stuff on the intake-manifold bolts.

Have some extra razor blades around and be sure to cover the lifter valley under the intake with old shirts or rags etc.Same with the ports,stuff rags in them to keep debris out.I prefer to use a coarse wirewheel on a drill to get remaining gunk off the gasket areas off the heads.The razor blades work great for scraping off the RTV on the ends.

Its a pretty easy job and just make sure the gasket sealing areas will be SUPER CLEAN and dry of everything before new gaskets and sealant.

:cheers: