Vortec 5.7 Intake Manifold Sealing Recommendations

[BamaBowrider 208]

I pulled the intake manifold off of this replacement engine because there was an oil leak on the rear which I traced to the seal between the manifold and the block. Once it was off there was about an 1/8" gap between the bead of silicone and the gasket. Pretty sure that is my culprit as the other three "corners" were sealed up and dry.

Anyway, reading the manual it calls for Loctite 5900 for the bead of sealant front and back, will Permatex Ultra Black or Orange (oil and gas resistant) do the trick? Also, it calls for Perfect Seal around the water jackets on the gaskets, the ones I removed had nothing at those locations....the engine was always dry there during last season.

Suggestions and recommendations please.

 

[alldodge]

Always best to tell us which 5.7

Loctite 5900 is just silicone and yes Permatex will do fine

If your using a Felpro marine intake gasket I would just use the gasket and no perfect seal. Manual does list to use quicksilver rtv in a bead across the ends

 

[alldodge]

Oh, can use perfect seal on the intake bolts

 

[BamaBowrider 208]

Always best to tell us which 5.7

Loctite 5900 is just silicone and yes Permatex will do fine

If your using a Felpro marine intake gasket I would just use the gasket and no perfect seal. Manual does list to use quicksilver rtv in a bead across the ends

Only info I have for the engine is that it's a 95-00 Vortec Gen 1, 880 casting.
Left side bell housing casting:
GM 5.7L
SMCO
B069
Right side bell housing casting:
10243880

Felpro gaskets were on the motor, I purchased the equivalent Sierra brand

 

[BamaBowrider 208]

Oh, can use perfect seal on the intake bolts

There was some sort of white sealant on the bolts, still somewhat soft

 

[alldodge]

The best way is with the motor serial number. If not on top the motor, look above the starter for a plate.

The white stuff is thread sealant

 

[BamaBowrider 208]

The best way is with the motor serial number. If not on top the motor, look above the starter for a plate.

The white stuff is thread sealant

I went down this rabbit hole when I first purchased this boat.....there is no tag on the engine above the starter. I was able to get in touch with the shop that supplied the rebuilt engine........this is the line out of their engine serial ID numbers from their website:
the 2 or 4 is in the main cap column and the one piece is in the rear seal column

 

[alldodge]

All good for what were doing now

 

[BamaBowrider 208]

I knew the white stuff on the threads was sealant, just didn't know what type/brand. The Seloc manual that I have says to use loctite on the threads. These bolts clearly had sealant and not loctite.....so wondering which way to go??

 

[alldodge]

Loctite is the name of the manufacture, they thread sealant and lots of other stuff. The white might be Permatex 59214 high temp

 

[Lou C]

When I did mine (Pre Vortec) I used Fel Pro intake gaskets & a bit of Permatex Aviation on the water ports and Permatex Ultra Grey on the China wall. No leaks 5 years later. BTW on the pre Vortec there are no locating pins to hold the gasket in place so the Permatex on the water port areas holds the gaskets in place while lowering the manifold down on the gaskets.

 

[BamaBowrider 208]

Loctite is the name of the manufacture, they thread sealant and lots of other stuff. The white might be Permatex 59214 high temp

Yes, understood.....I have some of the #242 blue threadlocker on hand. So is it better to seal or lock the threads?

 

[BamaBowrider 208]

When I did mine (Pre Vortec) I used Fel Pro intake gaskets & a bit of Permatex Aviation on the water ports and Permatex Ultra Grey on the China wall. No leaks 5 years later. BTW on the pre Vortec there are no locating pins to hold the gasket in place so the Permatex on the water port areas holds the gaskets in place while lowering the manifold down on the gaskets.

These gaskets/cylinder heads have the locating pins.....I did see a post where someone suggested making guide pins out of bolts to help install the manifold, might try that.
Searching around for Quick-Silver Perfect Seal, several sites say out of stock or superseded by the Permatex Aviation Form-a-gasket, is that why you went that route?

 

[alldodge]

Yes, understood.....I have some of the #242 blue threadlocker on hand. So is it better to seal or lock the threads?

You want thread sealer. Some the bolts ho into water jackets. Blue is only used in certain spots and there not many, and none on intake or heads

Use which ever you can find, perfect seal is not a must have

 

[Lou C]

You can use Perfect Seal, Permatex Aviation or Evinrude gasket sealer. I like the Evinrude stuff the best, but I don't think it really matters. When I replaced the cyl heads 5 years ago I used the Permatex and it was fine, also used it on the intake bolts, no leaks, no water in the oil.
Remember that the torque specs on the Vortec intake is different and a lot lower than on the Pre Vortec, the gaskets are kind of fragile vs the older Pre Vortec ones.

BTW as a salt water boater who keeps his boat on a rotating mooring 6 months out of the year, I can say that the Evinrude stuff is just great on lower unit bolts. I use it on everything on the lower unit, the impeller bolts, anode bolts etc and they do not seize up. The sealer keeps out the salt water and prevents corrosion. I also used it on thermostat housing bolts as well. The engine except for the heads is original, 34 years old, used in salt water over 20 years.

 

[BamaBowrider 208]

Thank you both for all of your info......one last question is torque spec. My manual says start at 26 inch pounds, increase to 106 and then finish at 216 inch pounds, does this sound correct??

I do have a picture of the tightening sequence.

 

[alldodge]

Correct
18 FT LB = 216 Inch LB