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Do not use ARP thread sealant on SBF head bolts

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I just found out the hard way, if you're bolting heads onto a late model 5.0, with the block whose outer head bolts penetrate the water jacket, DO NOT USE ARP THREAD SEALANT. I did, and the result is a big mess with coolant leaking from the rear bolts on both sides. Google popped up some on-line article on the SBF which advise to use Permatex No. 2. I hope they're right!
arp%20thread%20sealer.jpg
 
I'd like a little more info, please. Seems to me all one would have to do is clean the bolts (which you should do anyway) and it would work fine. They are not made of some alien metal to which silicone sealer cannot adhere. It's likely the oil on the bolt causing the problem. No?
 
What I've read on line is that RTV silicone will work but not if you need to retorque the head bolts, as some aluminum head manufacturers recommend. Permatex No. 2 is gooey brown stuff that does not harden, so the bolts can be retorqued without breaking the seal. ARP thread sealer is white runny stuff that does not harden either, but it also does not seal.

Another tip I got from my web search is that Stop Leak or similar products will fix a leaky SBF head bolt problem. Maybe if I spring a leak while on the road I would do this, but it seems half-assed when the car's in the garage and I can do it right.

Also be aware that it's only later 5.0 blocks that need the sealant. Don't know what model year the cutoff is, but I figure you can test your block with a compressed air nozzle in a bolt hole. If the nozzle pops out you've got a blind hole, if the air goes in no problem you've got a water jacket hole.
 
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Thanks for clarification. Now it makes perfect sense. It's more about bolts that require a second torquing than the product. The original post was kind of misleading.
 
No, not misleading. Do not use ARP thread sealer, period. My 5.0 has iron heads and I never retorqued the head bolts and they leak. ARP is not RTV silicone. I don't know what it is, chemically, and I don't know why they call it "thread sealer." It's runny white stuff that doesn't harden and doesn't seal. I am not sure why I'm not getting through on this, and I'm tired of trying.
 
I understood what you were saying. I wonder if it doesn't seal because of a reaction with the antifreeze?

From infinity and beyond.

Never argue with a Moron, they'll just drag you down to their level and beat you with experience.

If the women don't find you handsome, they should at least find you handy.
 
I use the ARP thread sealer all .the time, and it has never leaked with me. I use it on the screw in rocker arm studs in my 289 HiPo engines which definitely screw into the water jacket. A few times I've used it when the stud hole has been cracked due to an improper (chevy) stud being used, they don't have a flat base like the Ford ones do. Using them will often crack the hole slightly. Anyway it didn't even leak then. In my experience there has proved to be nothing wrong with the ARP thread sealer.

my 2 cents.

Z

PS. of course rocker studs are not head bolts, but you get the idea; antifreeze does not impact the ARP when the threads of the are good and clean. It's very important to chase the thread in the block, or heads in my case, and blow out the hole of the resulting debris.
 
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