Intake manifold bolt sealer

pablon2

Registered User
So I'm curious as to what people use to seal the manifold bolt threads. I know some use RTV. In the past I have used ARP thread sealer (white). When removing the manifold this time I noticed the bolts had loosened to about 3ft/lbs. When I installed the manifold last spring I followed the recommended torque procedure and torqued the bolts to about 17lbs. I retorqued them several times including a retorque the following day. Perhaps the thread sealer is the cause? Maybe I used too much? Maybe the heat cycles loosened the bolts over the course of a season?
 
I would say Yes, and Yes. The bolts will loosen on their own ... but the thread sealer probably contributed. Maybe it's just not right for this application, with such a low-torque fastener.

You could try RTV, or maybe even "aircraft sealant" or shellac.

I forget what I used last time ... Either RTV or some Permatex thread sealant, I think...
 
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I use Ultra Blue on any bolt I need to "SEAL".
I assume we are talking about bolt holes that are THROUGH to a water jacket or oil area not a blind hole?
 
Sealing, all I did was some rtv near the shoulder of the bolt at the top. I'll see how much the loosened in a week or so. I don't know that there is anything you could really do considering all the aluminum involved, the heat cycling and the stresses that the intake manifold sees. The only think I can think of is some self locking bolt like Stage 8 fasteners.
 
Sealing, all I did was some rtv near the shoulder of the bolt at the top. I'll see how much the loosened in a week or so. I don't know that there is anything you could really do considering all the aluminum involved, the heat cycling and the stresses that the intake manifold sees. The only think I can think of is some self locking bolt like Stage 8 fasteners.

I put the sealer on the threads.
IF it is though hole into water jacket you want to keep the water from coming up past the threads. Sealing the head to the mating surface is not the way to "SEAL"
 
I use teflon paste on the threads after cleaning the bolts with a wire wheel. It also helps to prevent them from corroding in the hole. Fel-pro makes a product but I just get the bottle of stuff from home depot.
Alan
 
I think the "Wizard of Whoosh" would tell you that if you have a problem holding torque your threads may be compromised. And, if memory serves, you should never use a compound to lock your threads unless the application specifically calls for it. This information is contained in a number of tech threads. Probably should consider new bolts.
 
I always use sealer on intake bolts that could leak coolant as well as water pump bolts. The factory used it. Just don't go using loctite or anything like that. Silicone doesn't work either. It likes to get into the coolant.
Alan
 
LOCTITE!? NO!!

Loctite ONLY on bolts that require it...Intake bolts do not require it.
That would be VERY bad on intake bolts.

BUT as I was corrected below if it is JUST a sealer and not have a locking characteristic... ok
 
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Boy, lots of sarcasm in this thread. :rolleyes: The Ford factory service manual calls for thread sealant but does not specify the type. I believe this is because when the bolts were new they had sealant pre-applied as do many OE bolts.

However, to answer the original poster's question, the correct sealant is Permatex High Temperature thread sealant. This is a hardening sealant. Other brands are acceptable as well.

Wizard of Whoosh. :D That's a good one.
 
"Wizard of Whoosh"

Just tryin to help. Maybe the good folks at the Ohio Dept of Motor Vehicles could grant you an exception for additional letters on the license plate.
 
Boy, lots of sarcasm in this thread. :rolleyes: The Ford factory service manual calls for thread sealant but does not specify the type. I believe this is because when the bolts were new they had sealant pre-applied as do many OE bolts.

However, to answer the original poster's question, the correct sealant is Permatex High Temperature thread sealant. This is a hardening sealant. Other brands are acceptable as well.

Wizard of Whoosh. :D That's a good one.

Dave,

While we are on the intake manifold topic....What is your current thinking on the torque specs for the SC intake manifold and can you explain why the 3.8 NA lower intake specifies the same bolts being torqued considerably more ?

David
 
i remember reading a thread on intake torque value's about 2 years ago. i cant remember exactly why, i think it had to due with the intake temps being higher in combination with boost that the intake could warp if the bolts had to much toque.

as for the loss of torque on the bolts after a year! well thats easy to explain. what happens if you take a hammer and smack a bud can once? you get a crumpled bud can
now if you take the same hammer and smack a bud can 500,000 times what do you get? a thin bud sheet of aluminum.
this holds true for the gasket, intake bolt surfaces, and the bolts. after so many times of heat/cold, expansion and the retraction of all properties, vac to boost shifting torque pressures, and vibrations the torque values applied to the bolts will change over time. this holds true for all torque values of pretty much everything. more noticeable however in applications like ours.
 
as for the loss of torque on the bolts after a year! well thats easy to explain. what happens if you take a hammer and smack a bud can once? you get a crumpled bud can
now if you take the same hammer and smack a bud can 500,000 times what do you get? a thin bud sheet of aluminum.
this holds true for the gasket, intake bolt surfaces, and the bolts. after so many times of heat/cold, expansion and the retraction of all properties, vac to boost shifting torque pressures, and vibrations the torque values applied to the bolts will change over time. this holds true for all torque values of pretty much everything. more noticeable however in applications like ours.

This is entirely not true for multiple reasons.

The last few times I have swapped intakes, it took several times waiting about an hour between, and a full day after to check again before they would retain the torque value using no sealer. I double checked the bolts the last time I had the AR off and all the bolts were still tight.
 
This is entirely not true for multiple reasons.

The last few times I have swapped intakes, it took several times waiting about an hour between, and a full day after to check again before they would retain the torque value using no sealer. I double checked the bolts the last time I had the AR off and all the bolts were still tight.

Ryan,

How many foot pounds ?

David
 
I believe is was 22-25 ft. lbs., I know it wasn't the 11 that the manual calls for. These were also newer metric grade 10.9 black oxide coated bolts some with and some without washers due to the AR fitment. I may also have used some ARP lube but I can't remember for sure
 
I believe is was 22-25 ft. lbs., I know it wasn't the 11 that the manual calls for. These were also newer metric grade 10.9 black oxide coated bolts some with and some without washers due to the AR fitment. I may also have used some ARP lube but I can't remember for sure

That's pushing the upper limit of what you can torque an M8x1.25 grade 10.9 fastener to. I think the maximum rating is about 19 ft-lbs for dry threads, and less for lubed threads. So the bolts will stretch a little at that torque, and they aren't far from breaking.
 
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