Oil leak coming from intake manifold 4.3 Mercruiser

[easyloader]

I installed the intake manifold of my 4.3 mercruiser. After I ran the motor for twenty minutes the a oil appeared from the rear gasket which the one where you have to use rtv silicone to from the gasket. I also noticed that the bolts where loose. I tightened them up and still had the leak. So I the then removed and reinstalled the manifold. Cleaning off all the surfaces and reforming the front and rear gaskets. Everything seemed ok until I took it out on the water and was running around three grand when the leaks appeared from the front and rear formed gaskets. The manifold bolts needed some tightening. I'm using permatex ultra blue gasket maker.
What am I doing wrong.

 

[dubs283]

Re: Oil leak coming from intake manifold 4.3 Mercruiser

did you install the gaskets on the valley ends or just rtv??

did you torque the bolts to spec?? in the proper torque sequence??

 

[Bt Doctur]

Re: Oil leak coming from intake manifold 4.3 Mercruiser

Try the Black , heres the secret to RTV gaskets. clean the block surfaces with alcohol, install manifold gaskets with Perma-Tex aviation around the water ports. Now pay attention!!!!!!!!!!!!!!!!!!!
squeeze a 1/4 inch bead on the front and rear surfaces
carefully set manifold down on engine
install all the bolts finger tight.
Go to bed, let stand 24 hours

Silicone has cured into a 3/16ths thick solid bead
torque bolts to correct specs
Your all done.

 

[wrench 3]

Re: Oil leak coming from intake manifold 4.3 Mercruiser

Permatex Right Stuff has a thicker consistency and works well on wider gaps. The manufacturer says that you can squeeze it on, bolt it up and fire it up rite away.

 

[GaJeff]

Re: Oil leak coming from intake manifold 4.3 Mercruiser

X2 on waiting 24hr before torque. I was told that years ago when i had similar problems with V engines. The hardest part is being patient enough to let it cure. I always want to start it right up or only wait a few hours. Just remember.... There is nothing better than doing a job twice unless it's the third time.

 

[easyloader]

Re: Oil leak coming from intake manifold 4.3 Mercruiser

I'll switch to the avaition and follow you instructions.
Couple of questions I want to get it right this time.
When I lay don the bead I squeeze it out of the tube then smooth it out with my finger. Is this the right way to do it?
I also coat the manifold bolts thread with teflon paste?
What would cause the bolts to loosen?
Thanks

 

[old islander]

Re: Oil leak coming from intake manifold 4.3 Mercruiser

DO NOT smooth out with your finger. Lay a standing 1/4" bead and set the manifold in place. Then 24 hours later, torque the bolts in the proper order. Go around the first time and tighten to half the torque value. Then go around a second time and torque to full value. If you do this properly and in order you should not have any further problems. If done in proper order your bolts should stay tight.

 

[achris]

Re: Oil leak coming from intake manifold 4.3 Mercruiser

Which 4.3? There have been 3 generations of the 4.3 engine. The first was without a balance shaft, the second has a balance shaft but still the old heads, the third has the new (Vortec) heads. The torque for the manifold bolts is different according to which engine you have... Original, Gen II or Gen +... If you are unsure, post the engine serial number....

Chris.......

 

[easyloader]

Re: Oil leak coming from intake manifold 4.3 Mercruiser

It has a balancing shaft and vortex heads.

 

[achris]

Re: Oil leak coming from intake manifold 4.3 Mercruiser

It has a balancing shaft and vortex heads.

http://www.boatfix.com/merc/bullet/97/97_01.PDF

 

[easyloader]

Re: Oil leak coming from intake manifold 4.3 Mercruiser

thanks to everyone. I'll let everyone know how I make out. Hopefully I'll be test driving it this coming weekend

 

[easyloader]

Re: Oil leak coming from intake manifold 4.3 Mercruiser

Never made it it the water yet. I just need to finish a few things then run it on the muffs then head for the lake. Mothers Day will set me back.
One last questuon wthe manifold gasket kit recomended that I coat the bolt threard with thread locker. I already torque them down but should I remove one at a time and coat the threads with










I'm 90 percent ready to go just have to do a few things then run it on muffs then head to the lake. ck a day.Mother Day will set be ba I have one question,
when I bought the gaskets, they are plastic with rubber around the edges. The instructions on the package recommend using thread locker on the manifold bolts. Should I do this? If so, since the bolts are torqued sown I;ll remove one at at time coat them and torqued them down.
Anybody got any thought on using thread locker?

 

[wrench 3]

Re: Oil leak coming from intake manifold 4.3 Mercruiser

Never made it it the water yet. I just need to finish a few things then run it on the muffs then head for the lake. Mothers Day will set me back.
One last questuon wthe manifold gasket kit recomended that I coat the bolt threard with thread locker. I already torque them down but should I remove one at a time and coat the threads with










I'm 90 percent ready to go just have to do a few things then run it on muffs then head to the lake. ck a day.Mother Day will set be ba I have one question,
when I bought the gaskets, they are plastic with rubber around the edges. The instructions on the package recommend using thread locker on the manifold bolts. Should I do this? If so, since the bolts are torqued sown I;ll remove one at at time coat them and torqued them down.
Anybody got any thought on using thread locker?

I'm not sure what to make of the post. I'll assume it was computer problems.
Thread locker sounds like a good idea and not much extra work.

 

[achris]

Re: Oil leak coming from intake manifold 4.3 Mercruiser

I'm not sure what to make of the post. I'll assume it was computer problems.
Thread locker sounds like a good idea and not much extra work.

Looks like the cat






stood on the 'Enter' key for a while....

Chris....

 

[easyloader]

Re: Oil leak coming from intake manifold 4.3 Mercruiser

Ran the boat today and no oil leaks. Thanks everyone for your advice.