Best Thread Sealer?

[eriefeelin]

I have a 1990 MerCruiser 260 (350 Chevy).Is there something better than Permatex #2 to seal the intake manifold bolts?I seem to always get some oil bypassing the threads on the bolts and then the oil pools up between the intake runners.It's alway the same bolt too.I've resealed the bolts using the Permatex,but it might last one season at best.

 

[Robj]

Re: Best Thread Sealer?

I like to use the white paste thread sealer. Some like to use the teflon tape, but I think the other stuff works better. However you can load up the threads with the teflon tape and see how that works for you. Unfortunately bolt threads are not really designed for sealing.

Good luck and have a great day,

Rob.

 

[Manipulator]

Re: Best Thread Sealer?

what about using 3M 5200, would that work?

 

[Flukinicehole]

Re: Best Thread Sealer?

How about loctite thread sealer. It works great to keep bolts tight just dont use the press fit assist or you could have trouble getting the bolt out at a later date. I`v always used teflon paste and never had a problem, try this first.

 

[Robj]

Re: Best Thread Sealer?

I dont think 5200 is oil or high temperature resistant. I would put many wraps of teflon tape and see how that works. One drawback of teflon is you cannot let any pieces of tape fall off and get into your engine. Maybe use both the thread sealant and then some teflon tape?

Good luck

Rob.

 

[Bonus]

Re: Best Thread Sealer?

Teflon tape is not appropriate for intake bolts. I used Permatex, Ultra Black Maximum Oil Resistance RTV Silicone Gasket Maker on these and other critical area with great results.

"Fast-curing formula. Sensor safe, low odor, noncorrosive. Meets performance specs of OE silicone gaskets. Retains high flexibility, oil resistance properties through use of a patented adhesion system. Temperature range -65?F to 500?F (-54?C to 260?C) intermittent; resists auto and shop fluids and vibration.

Suggested Applications: Valve covers, oil pans, intake manifold end seals, timing covers, transmission pans"

Current engine (5.7L) is bone dry, no leaks.

Bob in CO

 

[Robj]

Re: Best Thread Sealer?

My experience with RTV is it more for sealing gasket surfaces, not threads. For sealing threads teflon tape or thread sealer paste are generally used. However, it doesn't hurt to give RTV a try.

Have a great day,

Rob.

 

[Bondo]

Re: Best Thread Sealer?

I'd think that Form-a-Gasket #2(Permatex #2) should work Just Fine........
But,......
I think you might be chasing the Wrong Gremlin.......
To the best of My recollection,..... Those bolts Don't intrude on any Oil Cavities.......

I'd Sooner Think your Valve Cover Gaskets are Leaking down onto the Intake manifold...........

 

[John_S]

Re: Best Thread Sealer?

The Merc service manual say to use Loctite Pipe Thread Sealer on the intake bolts. The RTV is used on the front and back of engine block.

The thread sealer is for the four inner intake bolts on a vortec engine. I'll have to check my other manual (its in the boat) for the earlier sbc. For some reason, I didn't think they required any sealant. I'll post back latter today.

Check the engine vent hoses. They look like PVC hoses. Are you getting allot of blow-by and oil dripping from the hoses?

 

[eriefeelin]

Re: Best Thread Sealer?

Hello and thanks for the comments.I went to my marine dealer to buy a couple new belts.I asked about what to use on those bolts and right away he knew it was the two center intake bolts that were leaking a bit.It is a common occurrence.He said to use Permatex High-Temp Red RTV Silicone gasket maker.I bought a tube of this to try.