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I noticed a portion of my front intake gasket is missing and it popped out in another spot. It's a 73 455 with stock intake-no smog. I don't see any oil leaking. I spoke with a guy that said it might cause a vacuum issue, although I don't notice the car not functioning properly. He said to spray soapy water on the area to see if the idle rpms change which he said would indicate a vacuum leak. I tried it and there was no audible change. What exactly does this gasket seal? What issues can I expect if I don't do anything about it? I have the aluminum pan installed which prevents oil from splashing onto the underside of the intake which may explain the lack of oil at the problem area.
As stated above it keeps oil from leaking out of the lifter galley area. If your not leaking oil, then clean the area well with brakeclean, let dry completely, and pack some RTV into that area as presentable as you can get it. Let it cure and hopefully will last some time before you really need yo pull the intake and fix it properly.
Most throw the rubber or cork ends away and use RTV in their place. Your gasket is steel not aluminum.
It is quite possible a portion of the front intake gasket "may" have dislodged - "if" it truly is the intake gasket itself. There's a good (better?) chance it may be some RTV sealant compound which has worked its way loose and appears to be missing. The intake gasket seals the intake manifold so as to form a tight seal to maintain both vacuum (1°) and keep oil from extruding out of the intake manifold (2°). If you have a vacuum gauge measure your vacuum. The soapy water test can be hit or miss - a vacuum gauge is a better test. Often times RTV sealant (used especially in fairly large amounts on the front and rear areas of the intake manifold) might break-away without any harmful effects. If the engine runs fine, no oil emanating from the front of the intake manifold, and you can validate you have a good vacuum, there's no reason to consider changing the gasket (if it is the gasket) - good chance it's RTV sealant, instead.
It seals the lifter galley…You don’t have ANY oil leaking out?
Thats bizarre if you don’t. Are you sure it popped out?
This is what it looks like under your intake manifold.
-peter
I'm pretty sure It's the gasket and not RRV. This picture helps. I didn't see any out leaking from the gap and down the front of the block,but there was a bit of oil at the base of the connection for the oil pressure gauge and around the block I'd number which is close. I tightened the connection nut and cleaned the area up after spraying the soapy water. I'll take it for a drive an see if oil is coming from the gap.
I would try packing some silicon, You have nothing to loose. I had a small leak with silicon years ago, did that to mine and still good, at least 15 years ago.
Keep in mind that the end rail seal is kinda U shaped, so it’s possible the outer part of the seal broke off, but there is still seal material between the rail and the intake.
Keep in mind that the end rail seal is kinda U shaped, so it’s possible the outer part of the seal broke off, but there is still seal material between the rail and the intake.
that may be the case. I took the car for a 120 mile drive and no oil was present.
It ain't broke don't fix it.
If you decide to monkey with it. Clean with "real" brake cleaner apply the "Right Stuff" RTV.
Mask the block and intake about a millimeter or two on either side of the gap using blue painter's tape. Work in the RTV into the gap then finger smooth it out.
Remove tape before the RTV sets up. It will look much neater this way.
Secondly, get rid of the plastic oil pressure gauge line. Repace with copper with a vibration dampening loop just before it enters the firewall.
Pic is just an example It can be round vs oval.
My car is a non ac car so yours may be different but there should be a rubber groomet on the upper passenger side firewall near the heater box. I bent the line in a 90 and ran it to the passenger side. Another 90 and followed the valve cover all the way back to the firewall. Then it gets bent upward and at an angle towards that hole. I put a loop inside the car behind the dash and then went to my guage cluster. Works pretty well. Around me,, they sell the lines at Orielly Auto Parts. Grab 2 the first time. About 30 bucks.
Originally Posted by droldsmorland
It ain't broke don't fix it.
If you decide to monkey with it. Clean with "real" brake cleaner apply the "Right Stuff" RTV.
Mask the block and intake about a millimeter or two on either side of the gap using blue painter's tape. Work in the RTV into the gap then finger smooth it out.
Remove tape before the RTV sets up. It will look much neater this way.
Secondly, get rid of the plastic oil pressure gauge line. Repace with copper with a vibration dampening loop just before it enters the firewall.
Pic is just an example It can be round vs oval.
When I was 16, back in 69, I helped a friend swap his 2b intake for a 4b and the rear gasket had slipped out. We were baffled as to why the car had no power. We took it to the corner mechanic and he sprayed starter fluid around the manifold and sure enough when he got to the rear the rpm went up. But, it sounds like you car drives fine and probably is fine.
