chevy exhaust manifold/heads

[red bandit]

99 Silverado 5.3L aluminum heads. Exhaust manifolds leak due to a couple exhaust manifold bolts have the heads broke off. Of course it's the farthest rearward bolts on both sides. I can't get at it good enough to drill them out so I am pulling both heads and do it right. I will be replacing the bolts with Dorman exhaust manifold replacement bolts. I got out the rest of the bolts, they don't appear to have anything like anti-seize on them. Should I put anti-seize on the new bolts?

The torque specs I find for torqueing the heads say torque to 90 deg. Do you have to have the special tool or can you get away with torqueing them with just a torque wrench? Torque to how many lbs?

How do you remove the wire on the knock sensor that is under the intake manifold? Do you need a special tool? Any and all help is greatly appreciated.

[jetmechmarty]

If you use anti seize on those bolts, you'll overtorque them with a torque wrench unless the anti seize was specified. I think turning them 90 degrees after seated, you can use anti-seize without worry.

Maybe this will help with the sensor. http://youtu.be/cGQ5VATlrgE

[IanDMacDonald]

I personally use assembly lube instead of anti-seize when re-installing "new" head bolts.

[crazy steve]

I'm pretty sure he's referring to the head bolts when he talks about '90 degrees'. You don't need a special wrench, but I'll bet those are one-time-use head bolts and they'll need to be replaced. You might look at ARP for reusable replacements, they may be as cheap or cheaper than new OEM.

And most antiseize doesn't work all that well on very high heat. Believe it or not, liquid Pepto Bismo works pretty good.

[motoman]

I'm pretty sure he's referring to the head bolts when he talks about '90 degrees'. You don't need a special wrench, but I'll bet those are one-time-use head bolts and they'll need to be replaced. You might look at ARP for reusable replacements, they may be as cheap or cheaper than new OEM.

And most antiseize doesn't work all that well on very high heat. Believe it or not, liquid Pepto Bismo works pretty good.

Hmmmm........I understood he was talking about the exhaust manifold studs.

edit: Re-read......maybe was referencing to both cases. Agree, the '90degree' thing is reference to the 'torque to yield' head bolts.

[red bandit]

Just to make sure I understand it.... start with new bolts. Tighten first pass of the head bolts, torque to 22 ft/lbs. Second pass turn the bolt 90 Deg. except the medium length ones turn 50 deg.



Cylinder Head Bolts First Pass all M11 Bolts in Sequenc 22 ft.lb
Second Pass all M11 Bolts in Sequence 90 deg.
Final Pass all M11 Bolts in Sequence
Note: Excluding the Medium Length Bolts at the Front and Rear of Each Cylinder Head 90 deg.
Final Pass M11 Medium Length Bolts at the Front and Rear of Each Cylinder Head in Sequence 50 deg.
M8 Inner Bolts in Sequence 22 ft.lb

[IanDMacDonald]

I believe those are dry bolt specs, so u'd want to torque less if the bolts are lubed.

[MPittma100]

Bolts

I would suggest buying or borrowing or finding someone who has a Chevrolet service manual for your application. Otherwise, you could end up doing this job a second time.

I have assembled a lot of engines and ALL of the head bolts require either a lubricant or sealant on the bolt threads. Typically, a "blind" bolt hole will require a (specific) lubricant whereas a bolt hole that goes into the water jacket will require a sealant. The service manual will tell you what lubricant to use on each fastener. This will include exhaust manifold bolts.

Specific lubricants will be engine oil or a moly based grease (ARP 100-9909). The best thread sealant for head bolts is made by ARP (100-9904). It works!

http://www.summitracing.com/search/b...t&autoview=SKU

The "torque angle" method has been used by GM since the early 2000s. This method requires a pre (lb ft) torque and a special tool to complete the required torque angle. These special tools vary in price - some are inexpensive. Not using this tool will leave you with an incorrect torque value. Proper cylinder head bolt torque is CRITICAL.

http://www.autozone.com/test-scan-an...que-angle-tool

[red bandit]

Thanks for the info.