Intake manifold gasket sealant???

[duped]

Hi, I am in the process of replacing intake manifold gaskets on merc 230 v8. What type of sealant is best to use, and where, how much, etc...bought Mallory marine gasket kit.

Been getting water in the oil past two trips. Can't be a crack, I winterized properly (drains pulled completely and holes chased with nails, all hoses removed, stored dry) every year for the past 4 years I've owned it. Also been using the boat a lot this season and the problem just surfaced well after the weather has been warm. I am to understand this is the only other reasonable cause, and I have never done this job before. Hopefully the leak will be obvious to me once I get the manifold off.

Thank you!

 

[Bondo]

Re: Intake manifold gasket sealant???

Hi, I am in the process of replacing intake manifold gaskets on merc 230 v8. What type of sealant is best to use, and where, how much, etc...bought Mallory marine gasket kit.

Been getting water in the oil past two trips. Can't be a crack, I winterized properly (drains pulled completely and holes chased with nails, all hoses removed, stored dry) every year for the past 4 years I've owned it. Also been using the boat a lot this season and the problem just surfaced well after the weather has been warm. I am to understand this is the only other reasonable cause, and I have never done this job before. Hopefully the leak will be obvious to me once I get the manifold off.

Thank you!

Ayuh,..... How Much water,..??

I'm not familiar with that gasket set,... The 1s I use have a tracin' of sealant on 'em,...

I toss the end pieces with any of 'em, 'n use silicone sealant,...
I run a nice bead from side to side, 'n let it skin up abit, Then plant the manifold,...

Wipe up any oozin's, 'n torque 'er down,...

Clean gasket surfaces are the Most important link to Success,....

 

[duped]

Re: Intake manifold gasket sealant???

Doesn't look like the original gaskets used any but I will put a light dab of silicone on them. Any color preference? I have some ultra black here now.

Here's photos of the tear down...conclusive evidence of gasket failure. One port had a break in the ring of black around the gasket, and had rust spot where the water was going in on both the manifold and head. Also note the "cheese" around the failed port is about 2X thicker than around the rear side where the gasket was presumably sealed. Always good to find evidence!






Couple other questions...how do I clean this junk out of the motor? I shopvacced the lifter valley, and sprayed oil down it, but I'm sure this cheese is everywhere. I've been told to change oil with a quart of kerosene then change oil again?

Also, what are the torque specs and pattern for manifold bolts? I have never even used a torque wrench so I hope it dont give me grief.

 

[Bt Doctur]

Re: Intake manifold gasket sealant???

NO SILLYCONE ON THE GASKET
Remove as much of the oil mix as possable.2 qts diesel, 2 qts of oil. run it for 10 minutes and drain it.
Replace oil and filter and run it some more.You cant remove all the moisture untill you run it at normal operating temp on the water, not idle temp.
Black rtv front and back, some Permatex Aviation around the water jacket holes, install manifold and bolts DO NOT TORQUE YET. Let rtv cure first, then torque to final spec.
Check the underside of the manifold under the Thermostat for cracking .