Sweating intake manifold gasket.

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Ben A...

Ben A...

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Hey there,
I just finished my first engine build and did the break in -- I'll probably make a different post about that experience... many questions. Everything looks good, I want to now move on to dialling in the idle, but I have one concern.

At the coolant ports around all sides of the intake manifold I noticed it the gasket looks wet and overnight as temperatures change it will sweat some coolant... Just a few drops. The coolant level hasn't been affected, oil looks fine and I have no indication it's a severe leak internally. I notice this every morning and it has been a few days since I ran the engine.

All manifold bolts are torqued to 35ft/lbs. They needed to be retorqued after break in. And I put thread sealer on the bolts when building.

I suspect this isn't normal and folks recommend I re do it, but I really don't want to... Am I boned?

Thank you for your time,
Ben

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I doubt that is wicking out of the gasket. Maybe it is if you have alignment issues or the manifold isn’t flat.

Just because it’s new doesn’t mean it’s flat.
 
yellow rose said:
I doubt that is wicking out of the gasket. Maybe it is if you have alignment issues or the manifold isn’t flat.

Just because it’s new doesn’t mean it’s flat.
Click to expand...
Do these Fel-Pro gaskets wick? It's certainly possible I have an alignment issue because I did struggle to get the bolts lined up properly when I put it in.
 
Ben Ainsworth said:
Do these Fel-Pro gaskets wick? It's certainly possible I have an alignment issue because I did struggle to get the bolts lined up properly when I put it in.
Click to expand...
One thing comes to mind- when you installed the manifold, did you remove the locating pins on the china walls, or drill the manifold ends to accept the pins? If not, that could explain your "struggle to get the bolts lined up properly", and the resulting mismatch in mating surfaces that could lead to the gaskets weeping...
 
Professor Fate said:
One thing comes to mind- when you installed the manifold, did you remove the locating pins on the china walls, or drill the manifold ends to accept the pins? If not, that could explain your "struggle to get the bolts lined up properly", and the resulting mismatch in mating surfaces that could lead to the gaskets weeping...
Click to expand...

Well that explains what those little holes in the end rails are... I guess a previous owner removed those locating pins. Good to know. I've only done the intake manifold a few times, usually without issues, but this time it was a little stubborn to line up... I guess I just screwed it up. I imagine it's advised I replace the gaskets before running the engine again?
 
Ben Ainsworth said:
Well that explains what those little holes in the end rails are... I guess a previous owner removed those locating pins. Good to know. I've only done the intake manifold a few times, usually without issues, but this time it was a little stubborn to line up... I guess I just screwed it up. I imagine it's advised I replace the gaskets before running the engine again?
Click to expand...
Don't worry about the pins not being there, people run without them all the time. The problem I was referring to is because new manifolds generally aren't drilled to clear these pins (which locate/retain the manifold end seals), so if you don't remove them or drill the manifold for clearance, the manifold can "rock" on top of the pins and not sit down where it belongs- which could cause a sealing issue. But if your pins were removed, that probably eliminates that possibility.
 
If you do end up replacing the gaskets, a light wipe of high temp RTV on the gasket around the coolant passages isn't a bad idea.
 
Thank you Professor Fate.
I guess I'll just accept that it's best I fix it now before I test drive. I was eager and hoping someone would say 'that's totally normal' -- pipe dreaming
 
Did you use sealer around the water jackets? I wouldn't run it till I pulled the intake, inspected it for the possible cause (could be heads or intake have been cut a lot), re-sealed with new gaskets and a RTV around the ports on both sides of the gaskets. Also, I use Indian head Shellac around the intake ports and RTV around the water jackets and china walls (thick bead across the china walls and a heavy dose in all 4 corners)
 
Ben Ainsworth said:
Hey there,
I just finished my first engine build and did the break in -- I'll probably make a different post about that experience... many questions. Everything looks good, I want to now move on to dialling in the idle, but I have one concern.

At the coolant ports around all sides of the intake manifold I noticed it the gasket looks wet and overnight as temperatures change it will sweat some coolant... Just a few drops. The coolant level hasn't been affected, oil looks fine and I have no indication it's a severe leak internally. I notice this every morning and it has been a few days since I ran the engine.

All manifold bolts are torqued to 35ft/lbs. They needed to be retorqued after break in. And I put thread sealer on the bolts when building.

I suspect this isn't normal and folks recommend I re do it, but I really don't want to... Am I boned?

Thank you for your time,
Ben

View attachment 1715554444

View attachment 1715554445
Click to expand...
When you built this engine did you have the heads and/or block deck milled?
If so how much?
 
318willrun said:
Did you use sealer around the water jackets? I wouldn't run it till I pulled the intake, inspected it for the possible cause, re-sealed with new gaskets and a RTV around the ports on both sides of the gaskets. Also, I use Indian head Shellac around the intake ports and RTV around the water jackets and china walls (thick bead across the china walls and a heavy dose in all 4 corners)
Click to expand...
Go to 9:50 of this video and you can see the RTV/gaskets right before I set the intake on. I don't use the cork end gaskets with aluminum intakes.
 
My intake manifold sealing process...
1213 Fel-Pro gaskets....
Gasket cinch by Edelbrock...
"The Right stuff" Black by permatex...
I coat both the heads and the manifold with gasket cinch. Then hang both of the gasket and coat both sides of those with gasket cinch.. I put a double stacked bead of the right stuff on both China walls with extra in all four corners. I put one bead in the same area across the manifold on both ends with a little extra in the corner. I smear a thin coat of the the right stuff around the water ports on the head and the water ports on the manifold.. never a problem.. (knock on wood)
Before I do any of this and everything's clean I will lay the gaskets down with the manifold and make sure all the bolts fit in nicely...
My-2..
 
has your block been shaved?

if you take enough of the block, then that basically brings the heads closer together, which in turn lifts the intake up, and away from proper sealing

there is a formula to calculate how much to mill of the mating surfaces of the intake to make up for this
 
Ugh. That’s a bit of sweating. As others have said, use some RTV around the coolant passage perimeter on the gaskets (front and and back). Did you use RTV on the coolant passages on the first install?

Do you also have a vacuum leak (whistling sound) once the engine is warmed up? I had one after installing my intake and had to re install it with new gaskets. I had troubles fitting the intake the original time (lining up the bolts to the threads) so sanded some of the gasket down (side that didn’t have the rubber printing on it). Clearly I sanded down too much which created a small vacuum leak once the engine was hot. I didn’t have coolant leak though.
 
A lot of help here! Thank you everyone.
I'll do everything again and follow directions.
The block has not been decked and the heads and intake manifold are almost new--I've sealed this system before I did the rebuild, so I'm fairly sure its not that. :/
I think I must have rushed the process in excitement to finish the build...

Most likely I screwed up the torque sequence as well as I cant access the middle bolts with my torque wrench.

Is it safe to re-use gaskets that look wet? I have the day off kinda want to dive into this now...
 
Ben Ainsworth said:
A lot of help here! Thank you everyone.
I'll do everything again and follow directions.
The block has not been decked and the heads and intake manifold are almost new--I've sealed this system before I did the rebuild, so I'm fairly sure its not that. :/
I think I must have rushed the process in excitement to finish the build...

Most likely I screwed up the torque sequence as well as I cant access the middle bolts with my torque wrench.

Is it safe to re-use gaskets that look wet? I have the day off kinda want to dive into this now...
Click to expand...
Some might, but I wouldn't reuse the gaskets. I'd spend the 17 bucks for the over the counter fel pro at your local parts store. Also, I just tighten them up - I've never used the torque wrench on a intake. Just tighten them kind of like a tire - circle around side to side starting with the middle bolts.
 
Ben Ainsworth said:
A lot of help here! Thank you everyone.
I'll do everything again and follow directions.
The block has not been decked and the heads and intake manifold are almost new--I've sealed this system before I did the rebuild, so I'm fairly sure its not that. :/
I think I must have rushed the process in excitement to finish the build...

Most likely I screwed up the torque sequence as well as I cant access the middle bolts with my torque wrench.

Is it safe to re-use gaskets that look wet? I have the day off kinda want to dive into this now...
Click to expand...
I wouldn't re-use them, if nothing else there's the off chance that it's a gasket flaw. Get new gaskets. Wouldn't it just ruin your day to redo it and still have it leak?
 
Ben Ainsworth said:
A lot of help here! Thank you everyone.
I'll do everything again and follow directions.
The block has not been decked and the heads and intake manifold are almost new--I've sealed this system before I did the rebuild, so I'm fairly sure its not that. :/
I think I must have rushed the process in excitement to finish the build...

Most likely I screwed up the torque sequence as well as I cant access the middle bolts with my torque wrench.

Is it safe to re-use gaskets that look wet? I have the day off kinda want to dive into this now...
Click to expand...
I have never re-used any gasket it's just not worth the chance, again!...
you'll be into most of your day getting it off and getting everything re scraped and re cleaned up...
I've never used a torque wrench on an intake manifold. Just a 9/16 wrench...
Let all the RTV and all dry overnight at the very least refill the water and start it up drive it let it get completely cold and retighten the intake manifold...
 
Ben Ainsworth said:
Most likely I screwed up the torque sequence as well as I cant access the middle bolts with my torque wrench.

Is it safe to re-use gaskets that look wet? I have the day off kinda want to dive into this now...
Click to expand...

Yeah Canada Day means you’ve got the day off! Although it would be exciting to fix it today, letting the RTV set overnight would be best.
 
Ben Ainsworth said:
A lot of help here! Thank you everyone.
I'll do everything again and follow directions.
The block has not been decked and the heads and intake manifold are almost new--I've sealed this system before I did the rebuild, so I'm fairly sure its not that. :/
I think I must have rushed the process in excitement to finish the build...

Most likely I screwed up the torque sequence as well as I cant access the middle bolts with my torque wrench.

Is it safe to re-use gaskets that look wet? I have the day off kinda want to dive into this now...
Click to expand...


Before you take it apart, just give a good Re-tightening of the bolts.

As long as you went inside out and side to side, there is no magic torque “sequence”.
 
Also, to properly torque the 4 manifold bolts around the base of the carb plenum, purchase a 3/8” drive 9/16” torque adaptor (Proto 5118). It also prevented me from removing the distributor as I used it to remove/install the intake manifold bolt closest to the firewall that also holds the throttle cable bracket.
 
j par said:
I have never re-used any gasket it's just not worth the chance, again!...
you'll be into most of your day getting it off and getting everything re scraped and re cleaned up...
I've never used a torque wrench on an intake manifold. Just a 9/16 wrench...
Let all the RTV and all dry overnight at the very least refill the water and start it up drive it let it get completely cold and retighten the intake manifold...
Click to expand...
Between the aluminum manifold and the aluminum heads, all the factory torque values are out the window anyways- I'm sure the head manufacturer has some recommended values to use, but like many others, I tend to use the "FAR" method ("Feels About Right").
 
Last edited:
H22A4 said:
Also, to properly torque the 4 manifold bolts around the base of the carb plenum, purchase a 3/8” drive 9/16” torque adaptor (Proto 5118). It also prevented me from removing the distributor as I used it to remove/install the intake manifold bolt closest to the firewall that also holds the throttle cable bracket.
Click to expand...
Great tip! Will do this. Thank you.

As H22A4 pointed out its Canada Day so all the shops are closed. Dang!!

Ugh, this is so sad... Finished the build, broke in the engine and now I cant get the gasket in time before I have to hit the road for work for three weeks!

Thank you everyone. You always save the Duster from myself.
 
how does this happen? Is it that coolant is sneaking under the gasket because the seal is bad or it's misaligned? is it normal for a gasket to get wet like that?
 
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