DIY intake questions

[steve3140]

Quick note to thank everyone who has posted their comments / solutions to replacing their intake manifold gasket. I did mine over the last week or so with the Fel-pro kit I picked up from AZ. Turned out to be a fairly simple, straight forward task, took my time, took plenty of photos, labeled connectors etc. Marked the distributer, housing, and rotor in about 3 places. I did not have to remove the power steering pump, but unbolted the bracket and slid it forward out of the way. Also, since the radiator was drained, i pulled and cleaned it.

I ran into two snags, the first was the ERG pipe that comes up on the driver's side exhaust manifold, across the intake and connects opposite the heater core quick disconnect. I ended up destroying the pipe trying to get it off of the intake manifold and had to buy a new one (probably should have WD-40'd it the night before, but oh well). The second snag was cleaning out the bolt holes - I was runing the tap down the bolt holes in the head (very back one, passanger side), I slipped and managed to snap off the tap flush with the head. If this happens to you, look for a Walton tap extractor ($13). Picked one up and in 30 seconds had the broken tap out and was ready to move forward.

There has been some discussion on whether or not to put a sealer on hte gasket or install it dry. I opt'd to put a thin smear of permetex on both sides of the gasket aroudn each port. Figured it couldn't hurt. Also sacrificed a few papermate pens to make sure the manifold was aligned properly (Thanks Suburban-97) and installed the manifold and torque'd it down. There was some discepency in the torque setting, I read both 11 ft lbs and 30 ft lbs. Since most were listing it as 11 ft lbs, thats what I went with, seems a bit light tho. Next day I spent probably 3 hours to get everything back on, including replaceing the plugs, wires, and rotor.

After everything was done, I realized that the o-ring in the heater hose - manifold quick disconnect was screwed up. I sprayed the old one down with WD-40 the night before and the next day, it unscrewed without any problem and replaced it with an aftermarket one. If you are getting ready to do the job, just spend the $15 and pick one up with the gasket set, from what I have been reading - I got lucky, its another problem point and would be much easier to fix with the manifold off and on the bench.

Got it all put back together and started it up. Noticed a pretty good leak coming from the rear passanger side of the engine, to the point of having a nice puddle on the garage floor. And after some looking around, feeling for a leak, swearing etc., I pretty much ruled out the gasket as being the source. It was too big of a leak to be coming from the intake. However, before I tore it apart again, I rented a pressure tester and pumped it up to 16 psi, and watched the pressure drop. Water now running down the front of the engine, front of intake manifold? water pump? Then noticed that I never snapped the hose clamp back in place for the heater core line where it attaches to the water pump - idiot, idiot, idiot.. I think the fan was pushing enough air that the water was running along the manifold to the rear and running down the backside of the block. With the pressure tester, gravity took over and it just ran down the front. Fixed that and she held 16 psi for 45 minutes - put on the radiator cap and started it up. Haven't noticed a leak since.

Again, thanks everyone for your previous posts and insights / tips, they were a big help.

[J-Ri]

Originally Posted by steve3140

There has been some discussion on whether or not to put a sealer on hte gasket or install it dry. I opt'd to put a thin smear of permetex on both sides of the gasket aroudn each port. Figured it couldn't hurt. ... There was some discepency in the torque setting, I read both 11 ft lbs and 30 ft lbs.

It's too late now, but I believe it even says in the instructions NOT to use any sealer except on the block between the heads. The gaskets are designed to be installed dry.

11 sounds right. some are 18, or anywhere in between. GM changed the spec at some point, hoping to aleviate the problem. As long as the torque is even on all bolts (except the diagonal bolts on some...), it should be fine.

[rprun54]

I hope this is the right place to post this. I am new to this forum.
I just completed the intake manifold repair on a Chevy Silverado w/5.0 litre engine.
To begin with, my coolant was disappearing from my tank. With a pressure gauge, I found it to be an external leak, an intake gasket. I had no milkey looking oil on dipstick or on filler cap. I did the repair using step by step instructions. Being very carefull not to screw up.But I think I did.
After I got manifold replaced, I connected all hoses then pressure checked. Every thing seemed OK. I then put everything back together.Changed oil and coolent. Started engine and it ran great.Then things went to crap. Service engine light came on and engine started smoking. White smoke. I knew it was water. Oil was milkey now. What could I have done to cause this? I have an internal leak now. Could it be the new gasket?
Will have to redo job. Will I need to buy new gaskets again or can I reuse these? I think I can do job in 1/2. the time this time

[rhandwor]

Your taking a big chance on doing the job again using the old gaskets. If you used a proper torque wrench. I would say you didn't get the gasket surface clean. Clean bolt holes if any silicon sealer was used.Look real close at the plastic intake it may be cracked. Watch bolt length closely as this can cause big problems. I have had to use washers if my used supply of bolts was slightly longer than the defective bolt. Before tearing down check closely for a missing bolt.
Proper cleaning takes a while if you don't have an air buffer which uses sta- brite pads..

[98Tahoe5.7]

I want to remove the upper plastic part so I can clean the lower part in solvent, and replace a broken injecter shield. I removed all of the bolts holding the upper and lower together. The upper lifts about 1/8 inch, and spins around a bit, but won't come off. I removed the throttle tube and can see a bracket in there, but can't find how to release it. Anyone know how to split this intake in half?

[98Tahoe5.7]

OK ,I figured out how to split the top and bottom. Remove the 10mm bolts around the outside edge.
There is a big oval pod in the top middle of the plactic where the injection wiring pluged into. There are 16 electrical pins inside of it. Push down on that while you pull up on the plastic top. The oval shaped pod stays bolted to the alum. bottom during seperation. WOW is it dirty down in there.

[RainRider]

98 Tahoe5.7,
Since it's been a while since your post, you've probably already figured it out by now.
When I split my manifold, took the injection system out for cleaning - broke at least 3 of the retainers (they get extremely brittle) for the poppet valves into the intake.
Had to buy complete new injectors for each one I broke.
Hope your luck was different.

[Adventurer_96]

One of the reasons I bought my '96 Tahoe was because the transmission had been rebuilt, and another was because the intake manifold gasket had been done. But, I'm going to keep a close eye on it as I don't know what kind of gasket was used.

I removed the upper manifold this past week to replace the fuel pressure regulator to try and fix a fuel pressure problem I've been having, where fuel pressure drops off after the pump pressurizes the system. I was able to get the intake off and clean the inside, but as you guys have mentioned the fuel injector clips are very brittle. One had both clips broken, and another had one clip broken but also a tab on the bottom of it.

I was lucky enough to find a whole new spider assembly on eBay for the price of two injectors, so it's going in this coming weekend. If I find anything else to add, I'll mention it, but this is really a job anyone can do with a few tools and some patience.

[richiehat]

how can i find out were the fuel lines go into the runners on 98 tahoe i mixed one pair up thanks richie e mail richiehat@aol.com

[richiehat]

how did you know were to put back lines in intake runners they have to be in correct location.

[herkyhawki]

Hello, got a 1998 5.7L with very slowly disappearing coolant. Runs great and Oil looks fine.
Borrowed coolant pressure tester from Autozone. With engine not running, I Pumped up to 15 PSI. Pressure seem to hold, but then drops very slowly. Drops rom 15 psi down to 10 psi in about 5 minutes.
With engine running, coolant pressure is constant, not pulsing like I would expect if I had a bad head gasket. I suspect a small intake gasket leak. Question: does this look like a fix that can wait for warmer weather, or do I need to fix it now??

[rhandwor]

Water pumps have a habit of leaking then stopping for a week and starting again. Use a flashlight and check all hose connections. If you do another pressure test do it on concrete so if a heater core is leaking you can watch the drain for the evaporator case.
If you actually have an intake leak I would do the repair quickly. Check your dipstick do you notice any antifreeze in the oil. Check the coolant reservoir was any oil noticed.
I think you can rent small propane heaters which screw into a tank like a gas grill uses for your garage.
http://www.northerntool.com/ Model MH24T

[herkyhawki]

Got the intake gasket done. Thanks for all the info posted here. I have a couple tricks to add.
To find TDC #1 cyl when installing distributor: leave belt off and plugs out to make easier to turn crank. Install a hose (from compression tester or leak-down tester) into #1 spark plug and point hose to front of engine where you are turning crank. You can hear the air blowing out when you approach TDC, then watch for the marks to line up.

If oil-pump shaft is not lining up with dist shaft and you want to see which way the oil-pump shaft is turned: Get your digital camera and reach back there and take some photos down the dist. hole. Then look at the photos on the camera to see which way the shaft points.

[esalinas78]

I am going to try to replace the intake gaskets on my 01 Suburban, but am a little timid to try it. Does anyone have any step by step pictures or know where i can pring something out to help me? I have some automotive knowledge, but rarely tackle a repair like this on my own, HELP!

[CalifOkie]

Here is a tip to avoid a major headache. On the 1996 and up 350 R engines ( R being the eighth digit of the VIN#) it is very crucial to reinstall the distributor to the exact orientation as it was taken out. Failure to get it exact will cause a check engine light to come on and will require a position relearn procedure to be run on it with a GM or compatible scanner. To avoid this I like to use a straight edge centered on the rotor along it's electrode to the firewall then marking where it contacts the firewall. I then make another mark indexing the base of the distr to the intake manifold. Then I make an arrow on the plastic of the rotor pointing towards the firewall ( to keep you from dropping it 180 degrees out). Then take special care that the crankshaft is never turned until the distr is reinstalled with all reference marks aligning (including the straightedge contacting the mark you made on the firewall). Do not even hook the battery ground cable up until the distr is confirmed to be correctly aligned.