Small Block Head Bolt Leaks
Thread Starter
Intermediate
Joined: Mar 2003
Posts: 37
Likes: 0
From: Youngstown OH
Small Block Head Bolt Leaks
Just replaced heads on my 71 LT-1. Both rear (lower) head bolts are leaking (through the threads). Any helpful hints or methods to ensure these bolts won't leak? I've been told that these bolts commonly leak on older chevy small blocks. I just pulled both bolts, coated thoroughly with Permatex and re-torqed.
Thanks
Thanks
Drifting
Joined: Oct 2000
Posts: 1,825
Likes: 56
From: Shawano WI
Re: Small Block Head Bolt Leaks (SC71LT1)
All the head bolts on any stock block small block go into the water jackets and require sealer. Sometimes they will not leak with out sealer if you are lucky. Any good quality sealer will work (permatex, silicone, ect).
Drain the coolant out of the block, remove the bolt , apply sealer and retorque. Make sure that you look at all the bolts under the valve covers also because if they leak it will put coolant into your oil.
Drain the coolant out of the block, remove the bolt , apply sealer and retorque. Make sure that you look at all the bolts under the valve covers also because if they leak it will put coolant into your oil.
Melting Slicks
Joined: Jun 2001
Posts: 2,429
Likes: 14
From: CA
Re: Small Block Head Bolt Leaks (SC71LT1)
I've found what works best on head bolt threads is Permatex Thread Sealant with Teflon, part no: 14A.
I had bad luck with Felpro Gray bolt prep p/n GRA2, & Felpro "tight", p/n 604. Both of the Felpro sealers were recomended to me, but they both leaked. They also harden up which makes a big mess with pieces of hardened sealant getting everywhere when you remove the bolts - the Permatex dosen't harden.
I had bad luck with Felpro Gray bolt prep p/n GRA2, & Felpro "tight", p/n 604. Both of the Felpro sealers were recomended to me, but they both leaked. They also harden up which makes a big mess with pieces of hardened sealant getting everywhere when you remove the bolts - the Permatex dosen't harden.
Le Mans Master
Joined: Jul 1999
Posts: 9,206
Likes: 17
From: Sewell NJ
Re: Small Block Head Bolt Leaks (71coupe)
I've found what works best on head bolt threads is Permatex Thread Sealant with Teflon, part no: 14A.
I had bad luck with Felpro Gray bolt prep p/n GRA2, & Felpro "tight", p/n 604. Both of the Felpro sealers were recomended to me, but they both leaked. They also harden up which makes a big mess with pieces of hardened sealant getting everywhere when you remove the bolts - the Permatex dosen't harden.
I had bad luck with Felpro Gray bolt prep p/n GRA2, & Felpro "tight", p/n 604. Both of the Felpro sealers were recomended to me, but they both leaked. They also harden up which makes a big mess with pieces of hardened sealant getting everywhere when you remove the bolts - the Permatex dosen't harden.
