Check your intake manifold bolts

[crackerjack1957]

I would not trust a ft.lb torque wrench to go that low either...........definitely use in.lb

 

[HEMIMANN]

I check them every oil change,i just use a 5/16" nutdriver ,if i can move them with it,out come the tools to tighten the bolts properly.

Yeah but getting an old fat guy on top of a tall truck in the middle isn't exactly easy. Never did get an engine creeper.

btw, i got a 2500, not a 1500. Ever look into using a nylock nut?

 

[danielmid]

Yeah but getting an old fat guy on top of a tall truck in the middle isn't exactly easy. Never did get an engine creeper.

btw, i got a 2500, not a 1500. Ever look into using a nylock nut?

They're bolts, not studs, so I don't see a way to make that work.

 

[HEMIMANN]

They're bolts, not studs, so I don't see a way to make that work.

High temp Loctite? (567)

LOCTITE® 567

LOCTITE® 567 is a white, 1-part thread sealant designed for the locking and sealing of tapered metal pipe threads and fittings. As an anaerobic-curing thread sealant, it cures when confined in the absence of air between close fitting metal surfaces and prevents loosening and leakage from shock...

www.henkel-adhesives.com

 

[danielmid]

High temp Loctite? (567)

LOCTITE® 567

LOCTITE® 567 is a white, 1-part thread sealant designed for the locking and sealing of tapered metal pipe threads and fittings. As an anaerobic-curing thread sealant, it cures when confined in the absence of air between close fitting metal surfaces and prevents loosening and leakage from shock...

www.henkel-adhesives.com

The factory bolts come with thread sealer on the threads as far as I remember.

 

[HEMIMANN]

The factory bolts come with thread sealer on the threads as far as I remember.

Well that's weird - if it's not high temp, maybe it's melting and allowing bolts to back out from vibration?

Otherwise the plastic molding is taking on a compression set for the bolt to loosen. Either way the design $ucks. Probably some junior engineer with no oversight (ask me how I can say that).

 

[Wild one]

Yeah but getting an old fat guy on top of a tall truck in the middle isn't exactly easy. Never did get an engine creeper.

btw, i got a 2500, not a 1500. Ever look into using a nylock nut?

I usually check them when the trucks up on ramps while the oil is draining,and a small 3 step stool/mini stepladder is what i use to reach the intake bolts,i even use it when i'm checking the cars bolts,just don't need the top step for the cars is the differance.
A stud might not be a bad idea though.
I've heard of guys going to 120 inch-lbs of torque on the bolts,but whether that'll lock them in better i can't comment on,as i kind of lean towards the manifold changing shape as the majority of the problem, not the bolts stretching.
Whether loctite would keep them from loosening off is a good question,but the issue with loctite is you use heat to loosen it,and the bolts run into the heads,so they are subject to enough heat to keep loctite softened up.

 

[HEMIMANN]

I usually check them when the trucks up on ramps while the oil is draining,and a small 3 step stool/mini stepladder is what i use to reach the intake bolts,i even use it when i'm checking the cars bolts,just don't need the top step for the cars is the differance.
A stud might not be a bad idea though.
I've heard of guys going to 120 inch-lbs of torque on the bolts,but whether that'll lock them in better i can't comment on,as i kind of lean towards the manifold changing shape as the majority of the problem, not the bolts stretching.
Whether loctite would keep them from loosening off is a good question,but the issue with loctite is you use heat to loosen it,and the bolts run into the heads,so they are subject to enough heat to keep loctite softened up.

The 567 is 'rated to' 400 F, whatever that means.

I wouldn't think top of aluminum intake head on liquid cooled engine would get hotter.

 

[Wild one]

The 567 is 'rated to' 400 F, whatever that means.

I wouldn't think top of aluminum intake head on liquid cooled engine would get hotter.

If you try it,let us know how it pans out. I have a habit of removing intakes every once inawhile,so i'm leaving the bolts alone,but i am curious if it will keep the intake bolts from loosening off,and if the bolts maintain enough torque to prevent leaks and codes from eventually popping up

 

[HEMIMANN]

If you try it,let us know how it pans out. I have a habit of removing intakes every once inawhile,so i'm leaving the bolts alone,but i am curious if it will keep the intake bolts from loosening off,and if the bolts maintain enough torque to prevent leaks and codes from eventually popping up

Will do. I have 567 Loctite for engine screws anyway. It's expensive.

I was once expert in design and analysis of bolted joints in fatique, I'll try to talk sons into doing the grunt work. Gotta remove bolts, wire brush threads, put goo on, hand tighten, then torque. X 10

I'm a good parts specifier and runner late in life!

Watching NHRA Nationals in Indy today.

 

[Wild one]

Will do. I have 567 Loctite for engine screws anyway. It's expensive.

I was once expert in design and analysis of bolted joints in fatique, I'll try to talk sons into doing the grunt work. Gotta remove bolts, wire brush threads, put goo on, hand tighten, then torque. X 10

I'm a good parts specifier and runner late in life!

Watching NHRA Nationals in Indy today.

Damn that sounds better then what i'm doing,lol. I haven't paste waxed our 300C since last spring,so it's getting some loving today with a hand carressed paste wax. The older i get,the more work it becomes to maintain a cars finish

 

[HEMIMANN]

Sheeeit, I finally got around to getting pine sap off the seats from a year ago woods work!

Pine sap makes good preservative, btw.

 

[Wild one]

it was a warning, not a quote that I broke a bolt all you guys assume, but that is not what was written so I really don't give a flying crap about what anyone has to say. First, learn how to read and don't assume something that was not said. simple, I've been working on cars and trucks for over 45 years and I don't like when some backyard grease monkey says smack about something I did not say.

If you didn't break a bolt,why are you saying it's a tendancy,and bringing it up. You're the only one who's claiming they break. Plus you're spreading false info,with saying the torque spec is 12 ft-lbs,when it's only 9 ft-lbs.That's a full 33% past what the factory torque spec calls for

 

[crackerjack1957]

Use a paint marker & make a small line on the head of the bolt & intake to see if they are actually loosening.
More likely bolts are stretching or seals/intake are compressing.

 

[pacofortacos]

My bolts were all very snug from the factory.

 

[HEMIMANN]

Geezus - ALL 10 of my intake manifold bolts were under-torqued by about half the spec 108 inch-lbs. The rearmost bolts (nearest the firewall) were very under-torqued.

Don't be fooled - there is red Loctite on all the bolt's threads. Red Loctite used to be their "permanent" high strength adhesive for assemblies not meant to be disassembled for routine maintenance. I attached a pic below for you to see one of my factory bolts. They FEEL 'snug' all the way out until the Loctite comes out of the threaded bore! They are NOT 'snug'!

The only way to tell is with a torque wrench, once the thread adhesive has hardened. We removed all 10 bolts (one at a time in spec'd order), I wire-brushed the original hardened Loctite out of the threads, then applied Loctite 567 Hi Temp adhesive, advertised for up to 250 C (482 F). If memory services, the regular temp Loctites are only recommended up to 150 C (300 F). I suppose liquid cooled aluminum cylinder heads don't get hotter than 300 F, but I use Hi Temp Loctite on all my engine joints - I got air cooled engines too.

Re-installed and torqued one bolt at a time in order, so as not to allow the seal between the manifold and head to release. Once all bolts reinstalled, retorqued them all in order. Used calibrated CDI (half Snap On) Torque Wrench. Then the rubber test....

Took truck out for a drive. Maybe it's psychosomatic, but I didn't feel the engine stumble or sputter at idle. Hmmm. So, did bolts loosen due to heat age-hardening of the Loctite? Did the plastic manifold deform under the bolt clamp load? Did both happen?

Don't know, but that intake manifold sure doesn't look glass-filled to me. I looks like a cheapo polypropylene blow mold with near zero compressive strength. To me, it's an improper (cheap) choice for an important sealing surface.

<end report / rant>

 

[danielmid]

Geezus - ALL 10 of my intake manifold bolts were under-torqued by about half the spec 108 inch-lbs. The rearmost bolts (nearest the firewall) were very under-torqued.

Don't be fooled - there is red Loctite on all the bolt's threads. Red Loctite used to be their "permanent" high strength adhesive for assemblies not meant to be disassembled for routine maintenance. I attached a pic below for you to see one of my factory bolts. They FEEL 'snug' all the way out until the Loctite comes out of the threaded bore! They are NOT 'snug'!

The only way to tell is with a torque wrench, once the thread adhesive has hardened. We removed all 10 bolts (one at a time in spec'd order), I wire-brushed the original hardened Loctite out of the threads, then applied Loctite 567 Hi Temp adhesive, advertised for up to 250 C (482 F). If memory services, the regular temp Loctites are only recommended up to 150 C (300 F). I suppose liquid cooled aluminum cylinder heads don't get hotter than 300 F, but I use Hi Temp Loctite on all my engine joints - I got air cooled engines too.

Re-installed and torqued one bolt at a time in order, so as not to allow the seal between the manifold and head to release. Once all bolts reinstalled, retorqued them all in order. Used calibrated CDI (half Snap On) Torque Wrench. Then the rubber test....

Took truck out for a drive. Maybe it's psychosomatic, but I didn't feel the engine stumble or sputter at idle. Hmmm. So, did bolts loosen due to heat age-hardening of the Loctite? Did the plastic manifold deform under the bolt clamp load? Did both happen?

Don't know, but that intake manifold sure doesn't look glass-filled to me. I looks like a cheapo polypropylene blow mold with near zero compressive strength. To me, it's an improper (cheap) choice for an important sealing surface.

<end report / rant>

View attachment 528030
View attachment 528031

Looking good, did you paint marker to see if the bolts are spinning?

 

[HEMIMANN]

Looking good, did you paint marker to see if the bolts are spinning?

Nah, I didn't go the full monty.

Getting old and didn't have any high temp marker paint. Wasn't doing a store run just for that.
Was glad I checked, but still disappointed with design. This should not be necessary.

 

[JHoward]

Geezus - ALL 10 of my intake manifold bolts were under-torqued by about half the spec 108 inch-lbs. The rearmost bolts (nearest the firewall) were very under-torqued.

Don't be fooled - there is red Loctite on all the bolt's threads. Red Loctite used to be their "permanent" high strength adhesive for assemblies not meant to be disassembled for routine maintenance. I attached a pic below for you to see one of my factory bolts. They FEEL 'snug' all the way out until the Loctite comes out of the threaded bore! They are NOT 'snug'!

The only way to tell is with a torque wrench, once the thread adhesive has hardened. We removed all 10 bolts (one at a time in spec'd order), I wire-brushed the original hardened Loctite out of the threads, then applied Loctite 567 Hi Temp adhesive, advertised for up to 250 C (482 F). If memory services, the regular temp Loctites are only recommended up to 150 C (300 F). I suppose liquid cooled aluminum cylinder heads don't get hotter than 300 F, but I use Hi Temp Loctite on all my engine joints - I got air cooled engines too.

Re-installed and torqued one bolt at a time in order, so as not to allow the seal between the manifold and head to release. Once all bolts reinstalled, retorqued them all in order. Used calibrated CDI (half Snap On) Torque Wrench. Then the rubber test....

Took truck out for a drive. Maybe it's psychosomatic, but I didn't feel the engine stumble or sputter at idle. Hmmm. So, did bolts loosen due to heat age-hardening of the Loctite? Did the plastic manifold deform under the bolt clamp load? Did both happen?

Don't know, but that intake manifold sure doesn't look glass-filled to me. I looks like a cheapo polypropylene blow mold with near zero compressive strength. To me, it's an improper (cheap) choice for an important sealing surface.

<end report / rant>

View attachment 528030
View attachment 528031

Good info, thanks for that.

 

[Wild one]

I'm not disputing your claims, it's just that I hadn't heard anything about this being an issue. I've owned quite a few vehicles with composite intakes and I haven't had any issues with the bolts needing to be retorqued. It could just be a case of not owning any of those vehicles long enough to have issues with them. It's a good suggestion and I'll definitely check ours when I do the next oil change in a couple months. Thanks for bringing it up.

Did you ever get around to checking the bolts on your truck Mikeru