Dreaded intake oil leak

[lt1redz]

Repairing intake oil leak this weekend. Have Haynes manual.Searched previous posts on board and could't anything that could help. I do remember reading post regarding this repair. Besides Felpro gaskets what silicon sealer do I use. How long do I let it cure before reinstalling intake manifold. Should I tag everyting I remove ? Is there a site that I can go to for additional help ? Any help will be appreciated. By the way I have a 93 Z-28 auto. Thanks in advance for any help you can give me..

[DierDesire824]

make sure you load the back wall with sealant everyone this bored will most likely reccomend NOT firing it up for 24 hours after sealing the intake manifold up.

http://www.geocities.com/MotorCity/Downs/4013/ol.html

that's wolfman's write up has just about everything you need to know.
I used that one when I re-sealed mine.

[Joe 1320]

A little extra reading and pics.

http://www.f-body.com/forum/showthre...ht=Intake+leak

[lt1redz]

dreaded intake leak

Thanks for the info.One question. Do I let the silicon cure for 24 hrs before or after the intake is reinstalled and torqued down ?

[95FormulaResto]

I recently did the intake manifold fix using the resources of this website and other postings on the web. On Saturday, I did the disassembly, cleaning, and re-assembly to the point of bolting on the intake manifold and it took me most of the day (I'm slow). On Sunday, I re-assembled the rest and after 24 hours from the time I bolted on the intake, started the engine. Here are some tips from my experience:

1. Depressurize the Fuel System - By depressing the schroeder valve. If you’re not familiar, it's just a tire valve like fitting with a black screw-on cap protecting it. Unscrew the cap, press the valve.

2. Disconnecting Fuel Lines - Make sure you have the right tool to disconnect the fuel lines from the fuel rail. The tool is available at auto parts stores (about $6), but identifying the right one can be difficult. I lucked out and purchased the right one (very unknowledgeable clerks at Autozone) but then fumbled for about 20 minutes trying to disconnect the lines because of very poor directions that came with the tool and my fear of breaking something.

3. Marking - The injector connectors are labeled with the cylinder #, so no problem there. I marked a couple of vacuum lines using a sharpie pen just to make sure I got them back in the right place. I used a piece of cardboard with holes in it to keep the order of the intake bolts for later reinstallation in the same locations.

4. Fuel Rail - The fuel rail took a little more wiggling and prying to get off than I expected and a little more aligning and pressing to re-install it.

5. Be Careful with the Evaporative Purge Line - This is a solid plastic vacuum line that goes from the fuel line bundle, under the throttle body, to the purge solenoid. I overstressed it in my ignorance and snapped it (easy temp fix with a piece of hose and later ordered the right replacement part, but avoid damaging it).

6. Brake Booster Hose - I couldn't get the brake booster hose off of the intake. I had to cut it, losing about an inch of length in the hose (no problem).

7. PCV Hose - Upon removing the PCV hose from the throttle body, I discovered a crack in it. I tried cutting the cracked end off, but the crack just kept traveling. I replaced it temporarily with some hose from the auto parts store and later ordered the right replacement part (pre-formed hose).

8. Removal - The throttle body comes off pretty easily and the intake bolts aren't a problem (most of them seemed pretty loose).

9. Careful Cleaning - Put a towel or rag in the lifter valley to prevent debris from getting into the engine. When I removed the old intake gasket there were some little plastic alignment tabs that broke off in the holes. I had carefully pick them out so the new ones would go in. Don't forget to remove the rags when re-assembling.

10. RTV Sealant - Most seem to recommend PERMATEX ULTRA COPPER Hi-Temp RTV. That's what I used.

11. Re-installing the Intake Manifold - After you place the new gaskets and apply your beads of RTV, you have the challenge of lowering the intake manifold straight down on to the engine as not to smear the RTV all over the place. To make this easier, I partially screwed in 4 fuel rail screws and improvised some handles using electrical wire. This gave me something to hold on to and greatly eased lowering the intake into position.

Re-assembly was pretty straight forward after that. Use a torque wrench on the intake bolts to make sure it's secured properly. Make sure all of the injectors are lined up properly before giving the final pushes to seat the o-rings.

The old sealant on my engine actually looked to be in pretty good shape compared to the other picture in this thread. None the less, it was the source of most of my oil leaks both front and back. Good luck! Oh, and buy some of those cheap latex gloves they sell at the auto store. Your hands will thank you.

[95FormulaResto]

This was a pretty good step by step reference:

http://www.projecttransam.com/projects2.asp

[lt1redz]

Job completed...When started the idle stayed at 1000rpm then I remembered that I cracked the connector going to the IAC valve.Called local Chev dealer they wanted $46.00 for a new pigtail..Went to local u-pull-it and got one for $2.00. Thanx for all the help and sites that showed the step by step instructions. Just think no more $6.00 Mobil oil every 400 miles..Think I'll save that money for headers,etc,.

[Performin Norman]

When I did the one on my 94 Z28, I knew it was going to have positive crankcase pressure, so I used a sharp punch and dimpled the area of the block so it would hold the sealant better. Even going to the 15 psi pulley, I never had a problem with it.

I always apply the Permatex BLACK silicone and let it skin before I assemble the parts.