helicoil sealing problems

[roughidle]

I rebuilt my motor about 3 years ago (6 bolt) I did it on a really tight budget, so now since I can afford to have the car down for a little while, I have re-done the rebuild on the motor top to bottom. The only issue that I have left to sort out before starting to re assemble everything is an exhaust manifold stud. The top stud location on #1 cylinder was helicoiled by the machine shop the first time around 3 years ago when I had my valve job done. The problem with this that I have had since the first rebuild is I always had a slight oil leak from that stud even after using loctite thread sealer (high temp) on it. Is there any way to seal this stud up? Can I remove the helicoil, seal between the head and the coil, and re-install the same coil, or do I have to buy a new coil? Anyone that has had experience with this type of issue, please help me out. I want to start re-assembly as soon as possible, but I don't want to start until I get this last problem straightened out.....

 

[LiquidX]

I would try taking out the stud and then putting RTV into the thread and reinstalling the stud to see if it stops the leak before trying anything else first. That's of course if no one says that you can take out a helicoil and reinstall a new one. I personally have never use a helicoil so I can't give any info on that.

 

[rlacasse1]

I had the same issue and i used silicone and it sealed it right up. no leaking.

 

[rdejardin777]

+1 on the silicone

 

[dsmpat95]

Arp makes a teflon sealer for stuff like that. There are other brands, but dont remember off hand.

 

[Benshooter]

+1 for RTV. Go with the copper for that one, I'm pretty sure the copper has the best heat resistance. It's never let me down

Oh and as long as it's installed correctly, heli-coils are just as strong or stronger than stock threads, especially on aluminum parts. I've never heard of re-using a helicoil, I would just put a new one in.

 

[roughidle]

is using rtv silicone or the copper sealer going to do anything that the locktite thread sealer (high temp) I already used couldn't do? I guess my question would really be: is it possible for the area between the aluminum head and the helicoil be the problem and if it is, is there any way to seal that up without taking the helicoil out....

 

[BogusSVO]

the loctite is a thin sealer.... like stated above.... use RTV, ultra copper by permatex, 750* temp rating.

remove your stud... spray the hole with some brake clean, blow out with compressed air
put a small amount of RTV around the stud, install the stud, then let the RTV dry for several hours.

als NO you can not reuse a heilcoil (spring style) you will distroy it when you remove it... it dose not un-screw.

 

[Benshooter]

is using rtv silicone or the copper sealer going to do anything that the locktite thread sealer (high temp) I already used couldn't do? I guess my question would really be: is it possible for the area between the aluminum head and the helicoil be the problem and if it is, is there any way to seal that up without taking the helicoil out....

RTV is far better than locktite for leaks, and if you squirt a bunch in that stud hole and thread the stud in, you'll get every nook and crannie coated.

 

[rlacasse1]

Helicoils can be re-used as long as you don't try to take them out. I used them on rocker arms studs before and they work fine.