el es tu

A few weeks ago I found that one of the passenger side exhaust manifold bolts had no head - as far as I know, there has never been any work performed on the car that would require removing this exhaust manifold.

Apparently this is a common issue with Ls1s and ls2s...

Is this something that the emissions warranty would cover, or is it something easy/quick enough that I can diy? If I can just remove the broken bolt and put a new one in then no big deal (I read there is supposed to be a hex section between the bolt head and threading, and it looks like there is). Also what size/thread bolt would I need to replace it? I dont want to wait in order to get one bolt from the dealership.

Should I just upgrade all the bolts to arp and which part# would i use - they seem to have a few for ls engines?

Finally if Im going to do this (heres the slippery slope part), should I just say screw it and remove both exhaust manifolds and cats, portmatch and polish them (I have done this before on a turbocharged car and it helped significantly) and gut the cats (I can easily turn off DTCs for this with hptuners, am running stock mufflers so sound isnt an issue, and I dont mind the gasoline smell of no cats)? About how much more effort would it be to disconnect/ remove everything in that case?

Thanks!

glenB

It's not an emission component.

The bolts generally break because the manifold is warped, so I would check it with a level and send it to a machine shop for surfacing if needed.

ARP bolts won't hurt, LS exhaust bolts are the same

el es tu

It didnt looked warped compared to what Ive seen on other vehicles and I didnt see signs of exhaust leakage (black soot) however there is the ticking sound

Id like to just replace the one bolt, but if the manifold needs to come off its tempting to upgrade or modify the current parts

glenB

Bolt doesn't break on it's own. The uneven expansion/contraction is what snap the bolt. Some break evenly, others leave a *** to grap-a-hold of. Start spraying the bolts with some PB Blaster and start the car and let the heat wick the fluid into the threads.

Be advised that's it not uncommon to remove the head to have a machine shop remove the bolt. It all depends on how much bolt is sticking out.

4498

I had one break on mine. Passenger side rear bolt. When I installed my headers it was sticking out far enough I could get a small pipe wrench on it and it was tight, but came right out. If you do it yourself, do like glenb said and hose it down with some good penetrating oil.

cclive

Also, sometimes the bolts are weakened by overtightening at assembly, then age and heat cycles eventually cause the head to break.

el es tu

Picked up a replacement bolt and a few backups. Im going to attempt to remove the broken one without taking the manifold off. Should I check the torque on the others? I have seen 15 and 18 ftlb both quoted on this site.

btw the factory bolts came with what looks like a yellow threadlocker - so Im not sure where I want the torque value to be.

Thanks!



EDIT: For future reference here's the part number -

p# 11518860 - comes in packs of 5 but you purchase them individually - cost per bolt $1.21 from parts taxi and $1.84 msrp

cclive

That yellow stuff should be anti-seize compound. It contains tiny glass beads to keep the bolt removeable in the future...in spite of the numerous hot/cold cycles.