My intake manifold leaks like a sieve

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d100clubcab

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So I filled up the radiator yesterday and my intake leaks exactly like this video.
It is leaking from the rear drivers side
I guess I have to reinstall the gasket but who makes the best one that doesn't leak?
I have a 360 with knock off air gap intake.

 
Did you use a little silicone around the water ports? Felpro makes a better quality performance gasket that has a silicone rubber bead around the intake and cooling ports.
 
d55dave said:
Here you go. 30 seconds of internet search yields this.

Fel-Pro Performance Intake Manifold Gasket Sets SFL1213S3
Click to expand...

Thanks but multiple brands with multiple levels of quality of gaskets I wanted to get the tried and true FABO consensus on gaskets work great and which ones are trash.

I think I even installed this gasket set Yolo linked
Maybe I needed more silicone or a different type (I used the blue rtv)

Even to use the cork gasket at the front and rear vs rtv causes great discussions on here.
 
That's a bad leak! Like you did not know LOL. I am suspecting something other than just gaskets.

Question #1: Were there alignment pins in the front and back end rails? If so, and you did not pull them out, or drill matching recesses in the new intake, then the rear of the manifold may simply be jacked up and not sealing at all.
 
Any parts supplier can bring the better felpro in for you and yes, it does work better, especially when the alignment isn't perfect. As others have said you probably have bigger issues, possibly with the Chinese manifold.
 
The knockoff I used leaked almost that quickly. But it was sealed. The coolant was coming from casting porosity. Pull it and make sure the intake
Actually fits- then you can choose a gaskets that should work.
 
moper said:
The knockoff I used leaked almost that quickly. But it was sealed. The coolant was coming from casting porosity. Pull it and make sure the intake
Actually fits- then you can choose a gaskets that should work.
Click to expand...

This Knockoff ran fine on my engine for about 3 yrs and 50k of daily driven miles.
No leaks.
I replaced the heads and thats when the leak started.
 
If a new gasket doesn't fix it- it means you have a warped manifold and will need to re-surface it.
 
so, the intake was fine for 3 years
you replaced the heads (and from the looks of it, with junkyard heads?)
and now it leaks and we are blaming the intake?

who installed the intake 3 years ago?
and who installed it this time?

because if that is the same person, i would find it suspicious if he got it right the first time, but not the second

what has been done to the heads?
have we done anything to verify the intake mounting surfaces are clean and straight?
 
As Scooby-Doo would say... 'Ruh-roh' LOL

As said in post #8, time to back up and do some test fitting to see why the gaps are wrong at the back. With that size of leak, the coolant probably never got up high enough to show similar bad leaks up in the front.

Q2: Are the new heads re-manufactured or j-yard pulls or ???
Q3: Were the alignment sleeves in place on the head surfaces of the block to properly align the heads?
 
Operator error

I had the engine professionally built and it ran fine for 50k miles

Decided to put on some new heads so I grabbed a set from junkyard and had machine shop work them over.

Then I installed the fresh heads and now I have this leak.
So the leak is my fault.

There were no alignment pins in the block or manifold when I removed the manifold initially.

I guess I need to go back and ensure I install the alignment sleeves correctly
 
I suspected as much. This seems weird, but aluminum manifolds can be working fine on a running motor. Now you work on the motor and you remove the intake. When you re-install the manifold it leaks- usually in one of the four corners. It is warped! This has happened to me twice. It seems they warp after they are removed. A machine shop can re-surface the manifold (hard to find around here). Or replace the manifold.
 
d100clubcab said:
I guess I need to go back and ensure I install the alignment sleeves correctly
Click to expand...
I told you wrong.... alignment PINS, not alignment sleeves. They align the heads and head gaskets, which effects the intake surface positions. Those pins are in the block on the deck surface where the heads bolt on and should have been obvious; the head gaskets would have wanted to slip off! So if you laid the gaskets on and they just laid on the block, then then pins had to be there, unless you glued or RTV'd them in place. I can't tell you for sure HOW much of a difference it will make, but it is just another factor where thing can shift off a bit and be a part of a tolerance stack up that gets out of control.

Any small pins in the front or rear of the block walls above the valley should be removed... sound like they were before..

Did the heads get milled/surfaced when they were re-worked?

Murray said:
I suspected as much. This seems weird, but aluminum manifolds can be working fine on a running motor. Now you work on the motor and you remove the intake. When you re-install the manifold it leaks- usually in one of the four corners. It is warped! This has happened to me twice. It seems they warp after they are removed. A machine shop can re-surface the manifold (hard to find around here). Or replace the manifold.
Click to expand...
Interesting observations and experience!
 
Last edited:
Not attacking anybody - just saying what I had for experience with the imported ones.
So the new heads - were they milled? Back to my other question - did you make sure the intake fit the new heads properly, or did you just get the bolts in and go?
 
moper said:
Not attacking anybody - just saying what I had for experience with the imported ones.
So the new heads - were they milled? Back to my other question - did you make sure the intake fit the new heads properly, or did you just get the bolts in and go?
Click to expand...

I think I just fumbled the install
I don't think the manifold is warped
I doubt they milled that much as it was a $300 "go through p&p job"
I just bolted the intake on and started it up

The first time I had really high revs like I had leak in my intake gasket

No water was leaking then
I then reinstalled so now I have no high revs or intake leak but I'm leaking water out the back

3rd times the charm????


No guide pins were in this block
I used the intake aluminium guide sleeves and put rtv around the water ports but I guess I need to try again
 
nm9stheham said:
That's a bad leak! Like you did not know LOL. I am suspecting something other than just gaskets.

Question #1: Were there alignment pins in the front and back end rails? If so, and you did not pull them out, or drill matching recesses in the new intake, then the rear of the manifold may simply be jacked up and not sealing at all.
Click to expand...
I broke a cast iron 273/4 intake because I didnt notice the dowels in the 318 block I was bolting it down onto. I think it would crack under 35 ft/lbs torque on the bolts?>
 
pishta said:
I broke a cast iron 273/4 intake because I didnt notice the dowels in the 318 block I was bolting it down onto. I think it would crack under 35 ft/lbs torque on the bolts?>
Click to expand...

Not here.
The heads were off the engine for well over a year. I even posted pics here. I need to find them on my Google drive.
I know I have the pics showing no pins were installed.

I guess I need to rip this thing apart again and start over
 
d100clubcab said:
No guide pins were in this block
I used the intake aluminium guide sleeves and put rtv around the water ports but I guess I need to try again
Click to expand...
OK if you mean by guide pins, they are 2 pins on each side, 1/4" diameter IIRC, that are in the decks of the block, and stick up maybe 1/4" or 5/16". If they were gone, then you woulda known as you woulda had to do something to hold the head gasket in place while you dropped the heads in place (like glue them in place or put a couple of head bolt through the head and gasket to line them up). Maybe the pins pulled out with the old heads? Others ought to comment (so you don't pull the heads for no good reason!) but I would not expect any guarantee for the heads to align properly; the head bolts can't be counted on alone for proper alignment IMHO.

But hold on a minute: If you did install it 1st time with no coolant leaks, then I am starting to doubt that this is the issue. What engine is this? If you have a vacuum leak on a carburated engine, a high idle is not what you would get so that is perplexing too.

FWIW, I am not following what are the intake aluminum guide sleeves....???
 
nm9stheham said:
OK if you mean by guide pins, they are 2 pins on each side, 1/4" diameter IIRC, that are in the decks of the block, and stick up maybe 1/4" or 5/16". If they were gone, then you woulda known as you woulda had to do something to hold the head gasket in place while you dropped the heads in place (like glue them in place or put a couple of head bolt through the head and gasket to line them up). Maybe the pins pulled out with the old heads? Others ought to comment (so you don't pull the heads for no good reason!) but I would not expect any guarantee for the heads to align properly; the head bolts can't be counted on alone for proper alignment IMHO.

But hold on a minute: If you did install it 1st time with no coolant leaks, then I am starting to doubt that this is the issue. What engine is this? If you have a vacuum leak on a carburated engine, a high idle is not what you would get so that is perplexing too.

FWIW, I am not following what are the intake aluminum guide sleeves....???
Click to expand...

I'm headed to advance auto now to pick up a new set of FL1213 gaskets then rip it apart tonight and I'll take pics of the aluminum guide plates
 
I actually had steel gaskets installed
Seems like a lot of blue rtv was missing from this drivers so read water hole
I used the fl1213 today (which are felt)
I'll let it cure overnight before I test it out

---https://i.imgur.com/cgzTtBq.png


cgzTtBq.png
 
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