Replacing Intake Manifold Bolts

[willtel]

I've been messing around under the hood to clean up some things I don't like the look of and I want to replace the bolts for the intake manifold with stainless ARP fasteners.

I ordered a bolt kit and thought it would be easy enough to replace one bolt at a time. As soon as I touched the first bolt with a wrench water started to seep out so I tightened it back up and stopped.

If I drain the coolant is it safe to replace these bolts one by one or am I asking for trouble? The engine is a 302 with an Eldelbrock aluminum intake.

IMG_5520 by willtel, on Flickr

 

[centex77]

You can do it one at a time. Done it plenty with head studs. Just be sure to put a sealer on the bolts going through the water jackets. I also replace them in the pattern of the torque sequence. Don’t know if it matters but it can’t hurt.

 

[Steve83]

None of the bolts go into the coolant journals. Yours are leaking coolant because the intake manifold gaskets are leaking. The bolt heads are NOT intended to be part of the coolant system, and leaving them that way will cause them to rust away. It may also result in the engine hydraulic'ing - even at high speed, which wouldn't be funny. For the cost of new intake gaskets & a little coolant (you can catch & reuse what's in there now), you could fix it right. This & the NEXT few captions explain one way:


(phone app link)

 

[willtel]

Thanks for the insight Steve. Just to clarify nothing is leaking currently, oil is clean. I just want to swap the bolts out because the stainless ones will look better than the corroded mild steel ones in there now.

I started with the bolt closest to the thermostat and as soon as I loosened it coolant started to seep out. I think I'll drain the coolant as it needs to be flushed anyway and proceed with caution using the torque sequence you mentioned.

 

[blubuckaroo]

Willtel...
Did you use Fel Pro 1250 intake gaskets or a knock-off to that with no steel lamination in it? Those are known to fail like that when using an aluminum intake.
Those bolt holes are blind and what you're describing is an indication that the gasket is starting to fail.

 

[willtel]

Willtel...
Did you use Fel Pro 1250 intake gaskets or a knock-off to that with no steel lamination in it? Those are known to fail like that when using an aluminum intake.
Those bolt holes are blind and what you're describing is an indication that the gasket is starting to fail.

I didn't build the engine so I'm not really sure what is in there. It was built by a local dirt track engine guy who knows his stuff but it was assembled nearly 20 years ago now.

https://www.facebook.com/DA-Machine-Shop-173990479409431/

 

[Steve83]

...nothing is leaking currently, oil is clean.

Actually, yes: coolant is leaking from the coolant journal through the intake gasket into the bolt journal. But you're lucky it's not leaking past the bolt head or threads, or the other direction into an air journal, or down into the valley, or out the top of the gasket.


...YET.

...the stainless ones will look better than the corroded mild steel ones in there now.

Even stainless will rust (inside the manifold, where you can't see it) if exposed to hot stagnant coolant long enough.

 

[willtel]

Ok, I think I have it now. As always something simple turns into a bigger project.

 

[blubuckaroo]

It's just an easy repair that could become worse.

 

[KeithKinPhx]

I just pulled my aluminum intake today. Ordered a set of Edelbrock gaskets. Mistake. They have a clip in piece for the center water jacket. I threw them away and put in a Felpro set. I could see how a beginner might put that Edlebrock set in and leave the center bolts exposed to the coolant. Definitely need to drain coolant, pull intake and install new seals. Regardless of which brand you use you need to put a small bead of RTV around each water jacket. I did both sides of the gasket to be sure.
Good luck

 

[blubuckaroo]

That center port isn't a water port. It's the heat riser port. It's connected to the EGR exhaust rail in the head. It's purpose is to pass exhaust heat under the carb to atomize the air/fuel mixture.
Those inserts are made from a heat resistant material and give you a choice to use the heat riser or to block it.
If you look closely at this photo, you'll see that the end intake bolt holes are very close to the edge of the water ports. That's probably the point of your leak.

But again, I'd advise against using any of these intake gaskets that haven't got a steel lamination.
I prefer the Felpro 1250 S3. It has the same properties but has a steel reinforcement.
https://www.summitracing.com/parts/fel-1250s3/overview/

 

[willtel]

I got everything swapped out over the weekend. The old gaskets were Felpro but didn't seem to have a steel core because it took me hours to clean the old ones off. Everything seems to have sealed up well and I don't have any water in the oil. I have to flush the cooling system a few more times and I'll call this done.
Slippery slope by willtel, on Flickr

 

[Steve83]

All that rust in the coolant journals says you're not changing the coolant on-schedule. That will eat up the WP impeller, heater core, and radiator. MotorCraft VC-5 plus cheap grocery-store distilled water is best. Change it every 2 years regardless of miles.

 

[blubuckaroo]

Looks like you're going with the same Felpro 1250 gasket set.
Good luck with that.

 

[willtel]

All that rust in the coolant journals says you're not changing the coolant on-schedule. That will eat up the WP impeller, heater core, and radiator. MotorCraft VC-5 plus cheap grocery-store distilled water is best. Change it every 2 years regardless of miles.

I'm on it.

Looks like you're going with the same Felpro 1250 gasket set.
Good luck with that.

I replaced them with the ones you recommended. The picture is of the old gaskets right after I pulled the intake off.