Intake oil leak, anyone had any luck with

malc350 · 05-09-04, 08:10 AM

patching the leak up with RTV from the outside (i.e. without removing the intake)?

I posted a previous thread about intake gasket replacement and thought I did a real good job with cleaning the surfaces and bought another tube of RTV to make sure the front and back of the block are well sealed.

I still had a huge oil leak but that turned out to be the oil pressure sender and I also replaced the oil pressure switch for in surance.

I cannot believe that I have noticed a slight leak from the back of the intake again - it's very slight - on the passenger side where the intake meets the block and easily accessible if I remove the distributor.

Question is, has anyone had any success with repairing a leak like this by cleaning the external surfaces and sealing with RTV?

I don't really want to remove the intake again as I've actually done this twice and had a diiferent leak each time! Chances are I'll remove the intake to repair this leak and then have another leak elsewhere!!!

I find theis hard to understand. Is this an L98 thing, having to do the job over and over (and it's not a nice job!) I have only ever had to do this job once whenever I've done it, including on an LT1 where it was leak-free, first time!

Moonunit 451 · 05-09-04, 05:21 PM

Quote:

Originally Posted by malc350

patching the leak up with RTV from the outside (i.e. without removing the intake)?

I posted a previous thread about intake gasket replacement and thought I did a real good job with cleaning the surfaces and bought another tube of RTV to make sure the front and back of the block are well sealed.

I still had a huge oil leak but that turned out to be the oil pressure sender and I also replaced the oil pressure switch for in surance.

I cannot believe that I have noticed a slight leak from the back of the intake again - it's very slight - on the passenger side where the intake meets the block and easily accessible if I remove the distributor.

Question is, has anyone had any success with repairing a leak like this by cleaning the external surfaces and sealing with RTV?

I don't really want to remove the intake again as I've actually done this twice and had a diiferent leak each time! Chances are I'll remove the intake to repair this leak and then have another leak elsewhere!!!

I find theis hard to understand. Is this an L98 thing, having to do the job over and over (and it's not a nice job!) I have only ever had to do this job once whenever I've done it, including on an LT1 where it was leak-free, first time!

I kida doubt you'll have any luck with that approach. I'm sure it's a whole lotta fun doing this job on the TT

If you haven't tried it, people have great results with The Right Stuff. It's a black RTV available at many parts stores and is dispensed under pressure. A nice approx. 3/8's" bead forward and aft did the trick in one shot for me. Ya, it's an L98 thing

malc350 · 05-09-04, 05:55 PM

I just tried it today and I'm leaving it 24 hours to cure. Don't think we have "the right stuff" over here though I did get a tube of thick black RTV.

This is my last attempt before doing the intake thing again

Then I'll use a tube of RTV at each end

CKA_Racing · 05-09-04, 10:24 PM

Puttin RTV on the outside will not work. If it does, I'll be shocked if it last very long at all.

I use the "Right Stuff" RTV. I also dimpled the block and intake at the rear, this gives the RTV something to grab and hold on to. Let it cure for at least 24 hrs.
you think maybe your intake is warped?

malc350 · 05-10-04, 04:47 AM

What surprises me is that I used a lot of RTV and it looked well covered. Not sure if I left it 24 hours to cure.

Maybe it's ok to start the engine before the 24 hours is up to help the RTV cure (?) as I saw no leaks at all for a while with the car running. Maybe it's the forward motion of driving that causes the oil to splash against the back of the manifold?

The leak is actually very small. When I used a mirror (!) to look at the join between manifold and block I could see the gap was filled with RTV. I was just hoping that adding some from the outside might help.

Weird, I've never had to do this job more than once before...

86PACER · 05-12-04, 05:04 AM

I had to pull mine off again beacuse I used RTV the first time arround. I would highly recommend Permatex "The Right Stuff" Napa and PepBoys carry it. Also follow these techniques to the T and you will guarantee a leak free install. I've been absolutely leak free for about 4 months now. Having to pull the intake off again and again is not fun. Good luck.

http://corvetteforum.com/techtips/vi...=266&TopicID=5

malc350 · 05-13-04, 04:40 PM

Just had to bite the bullett and do the job again today. Still took a few hours. When I pulled the intake the reason was painfully obvious - I just didn't use enough RTV

After studying that brilliant link in the previous reply, this time I:

Scraped the head and intake surfaces with a blade
Cleaned the surfaces with carb cleaner more than once
Dimpled the front and back areas of the block and intake to give the RTV something to grip
Used a BIG bead of RTV front and back overlapping the gasket slightly
Put an extra bead behind the first bead (paranoia)
Put a thin coat of RTV around all port holes in gasket + thicker bead around water holes in gaskets
Only used FelPro blue gaskets (what else)
Torqued the intake gradually to proper value
Used semi-hardening sealer on bolts
said a prayer!

If this doesn't work nothing will. Just leaving the car to sit for 24 hours before driving. Actually I'm that paranoid that I might not drive it again!!!

malc350 · 05-13-04, 04:57 PM

add to list above:

also roughed up the surfaces with fine wet 'n dry paper too.

Hopefully this will all do the trick!

rrubel · 05-13-04, 05:18 PM

Whew. That article made me paranoid enough that I'm going to pull everything off the intake and redo it NOW, while it's still accessible. I *know* I moved mine when putting it on the block. Plus I probably used too thin a bead on the front and rear.
[RICHR]

86PACER · 05-14-04, 01:31 AM

I know for sure I moved my intake a little to align the bolt holes after it seated the first time arround. Perhaps that was my key mistake. I got it seated perfect this time without moving it. I found that the easiest way for me was to stradle over the motor with one foot on each front wheel, bend down at the waist, and lower the intake while looking at the bolt holes for proper alignment as I lower it. This gave me a view of both sides of the intake at the same time.