Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner

101 - 120 of 121 Posts

·
Registered
2008 chevy trailblazer_lt
Joined
·
6 Posts
Only 55,000 miles, but I think it cracked from a dose of cold water when I went through 18-20" Coyote Creek a couple of weekends ago in the desert with Only1Balto. Sigh...

So I took it off today. Even if I pay my trusted independent GM mechanic to put it back on, I was curious. Maybe too curious.

Yep. big fat crack:







Looking pretty empty in here:



Far rear:



Oops.



Final tally of siezed and torqued off manifold bolts in the head = 3.

:duh: :hissy: :ugh: :sadcry: :sadcry: :sadcry: :sadcry:

Of 11 bolts (8mmX1.25), the ones that broke are the farthest forward and the two farthest rearward. Almost impossible to see without a mirror. I even took off the power steering pump to see if the access got any better - still miserable. Even with a very short right angle drill, I have very little hope that anybody could get a screw extractor in there straight.

So - what's the betting that there's no way to fix this except remove the head and take it to a shop? I could drill and put in helicoils in the machine shop at work, but I'm really not looking forward to removing the head working in the dark after work every night. So I'll probably tow it to the mechanic tomorrow, take my lumps from him for being a dumb butt, and open my wallet. Sigh... :)


In my opinion..
You have to wonder when there are so many complaints about one part, and such a major part at that.
I love my 2008 trail blazer, but it also has a cracked manifold .
Now this is not the only site where the manifolds from the same engines are a constant complaint,.
Being as there are so many complaints about these manifolds it leads me to believe that it is a manufacturing problem and should be addressed as such.
As for tie rods and any moving parts I agree they break or ware out just as your tire do and often but the manifold is different.
I’ve always owned used vehicles all my life and NEVER have I had a manifold crack on me once this is a part that is suppose to last a lifetime, its not just a cost issue but also an environmental one.
I’m taking my trailblazer into the dealer Monday and I have copied some of these comments about the manifold problem, its being looked at by some sort of head mechanic, whose decision is apparently final .
After his inspection I’m going to let him see all these comments for its evident to me his decision well be swayed if they do not cover at least the part of the cost .
Let you know how things go if it dose not go well there’s always W5 lol
Tim Holden.
 

·
Registered
2008 chevy trailblazer_ltz
Joined
·
12 Posts
Does anyone think it might be worth putting header wrap around the new manifold (when i get it replaced)?? Just curious cuz this would be a royal PITA if it happened again. * I do plan on doing some off roading (probably wet condtions) and am wondering whether header wrap would benefit the manifold or not.:undecided
 

·
Registered
2008 chevy trailblazer_lt
Joined
·
6 Posts
Does anyone think it might be worth putting header wrap around the new manifold (when i get it replaced)?? Just curious cuz this would be a royal PITA if it happened again. * I do plan on doing some off roading (probably wet condtions) and am wondering whether header wrap would benefit the manifold or not.:undecided
there is kits you can buy things like skid plates to stop the water splashing upward into the motor compartment, works for keeping snow and ice build up to.
my 83 jimmy had them if you use your truck for off road you should have an ofroad kit intsald with the jimmy it was 1/4 alunimum plates one under the motor front end and grill area the other over the tranny i dont think there all that expsive to have made iether.:thumbsup:
 

·
Registered
2008 chevy trailblazer_lt
Joined
·
6 Posts
In my opinion..
You have to wonder when there are so many complaints about one part, and such a major part at that.
I love my 2008 trail blazer, but it also has a cracked manifold .
Now this is not the only site where the manifolds from the same engines are a constant complaint,.
Being as there are so many complaints about these manifolds it leads me to believe that it is a manufacturing problem and should be addressed as such.
As for tie rods and any moving parts I agree they break or ware out just as your tire do and often but the manifold is different.
I’ve always owned used vehicles all my life and NEVER have I had a manifold crack on me once this is a part that is suppose to last a lifetime, its not just a cost issue but also an environmental one.
I’m taking my trailblazer into the dealer Monday and I have copied some of these comments about the manifold problem, its being looked at by some sort of head mechanic, whose decision is apparently final .
After his inspection I’m going to let him see all these comments for its evident to me his decision well be swayed if they do not cover at least the part of the cost .
Let you know how things go if it dose not go well there’s always W5 lol
Tim Holden.
First post :
In my opinion..
You have to wonder when there are so many complaints about one part, and such a major part at that.
I love my 2008 trail blazer, but it also has a cracked manifold .
Now this is not the only site where the manifolds from the same engines are a constant complaint,.
Being as there are so many complaints about these manifolds it leads me to believe that it is a manufacturing problem and should be addressed as such.
As for tie rods and any moving parts I agree they break or ware out just as your tire do and often but the manifold is different.
I’ve always owned used vehicles all my life and NEVER have I had a manifold crack on me once this is a part that is suppose to last a lifetime, its not just a cost issue but also an environmental one.
I’m taking my trailblazer into the dealer Monday and I have copied some of these comments about the manifold problem, its being looked at by some sort of head mechanic, whose decision is apparently final .
After his inspection I’m going to let him see all these comments for its evident to me his decision well be swayed if they do not cover at least the part of the cost .
Let you know how things go if it dose not go well there’s always W5 lol
Tim Holden.

2nd post:
I have to say Chevy dealer looked after me.
As it turns out the manifold is covered under the drive train warranty witch is 160.000 I’m at 84000 was replaced no charge, immediately with no delay as soon as he saw that it was cracked.
My brother and I walked around town for 3 ½ hours then they came and picked us up to reclaim my trailblazer. Lol I still have 76000 might get one more out of them lmao.
 

·
Registered
2008 chevy trailblazer_ltz
Joined
·
12 Posts
Took my TB to the dealer yesterday morning. Got it back this afternoon purring like a kitten again. Its nice driving a vehicle that sound luxurious rather than like an 80's diesel. Once again, thank God for warranty.
 

·
Banned
2004 gmc
Joined
·
26,181 Posts
Discussion Starter · #106 ·
... if you use your truck for off road you should have an ofroad kit intsald ...
Um, yes. :yes: I am a bit familiar with offroading and fabricating skid plates. ;) Perhaps a very small bit. :tiphat

They didn't help. Not 20" of water at a particular speed (not too fast).







 

·
Registered
2005 gmc envoy_sle_xl
Joined
·
4 Posts
Cracked Manifold Club

As luck would have it my manifold crack turned up just before I was leaving on a week long camping trip. The trip includes pulling my 1996 22 ft. Gulfstream Conquest trailer, and a second trip to bring up my 1984 18 ft. Chris Craft Scorpion. I couldn't source a Dorman replacement locally, so I had to use GM parts. I picked up the manifold, gasket, dougnut, and bolts from a local dealer for a little less than $270. We did the work with the truck still hot from being driven in and after a thorough soaking with PB Blaster. All bolts came out luckily, and I believe a technique of tapping the bolts with a hammer and backing and tightening was key in accomplishing this. The job took about 4.5 hours. The next day I was hooked up and headed for the lake. Nothing like the sound of the l6 loaded down leaning into the mountain.
 

·
Registered
2005 gmc envoy_sle_xl
Joined
·
1,029 Posts

·
Registered
2008 chevy trailblazer_ls
Joined
·
105 Posts
Mine sounded like an unmuffled Harley for the first 2-3 miles, then the noise got softer until it was only about twice as loud as the Flowmaster 70 exhaust. I concluded it was an manifold crack rather than a exhaust gasket problem because it got quieter as it warmed up.
Love the info digging back gives you.

Sounds like what I am hearing now on my "08 TB, @ 50,000 miles. I called the dealer and said at start up I was idling at 1,000 RPM, he said TB’s are set for high idle at start.
I also mention at high idle start the car was loud as heck, like when I ran straight pipe out the back of my winter beater, “67” Michigan rust bucket Impala when I was a kid. He said bring it in we’ll take a look. Now I recall a few months back getting a letter from GM about manifold defects, leaks/cracks. I wonder!
 

·
Registered
2008 chevy trailblazer_lt
Joined
·
2 Posts
Another Manfold Cracked

Hi All
I just joined the forum and this is my first post.
The manifold crack on my 2008 Trailblazer last week.
Its going in to the dealership am 11/16. I usually work on the stuff myself, as over the year when I take something in to a dealership it comes back with more broke then fixed . And thats been my experience with this one too.

Took it in for and ignition problem ( it would start when the key hit the on position instead of turning to the start position ) got it back with the problem not fixed and a broken bezel around the switch .
The only reason its in the dealership I got a e-mail saying they had extended the warranty to cover this cracked manifold . But now I can't fined the e_mail.:duh:
Does anyone know where I can fined that bulletin ?
THX
Mike
 

·
Registered
2008 chevy trailblazer_ls
Joined
·
105 Posts
Love the info digging back gives you.

Sounds like what I am hearing now on my "08 TB, @ 50,000 miles. I called the dealer and said at start up I was idling at 1,000 RPM, he said TB’s are set for high idle at start.
I also mention at high idle start the car was loud as heck, like when I ran straight pipe out the back of my winter beater, “67” Michigan rust bucket Impala when I was a kid. He said bring it in we’ll take a look. Now I recall a few months back getting a letter from GM about manifold defects, leaks/cracks. I wonder!

Update: fixed free of charge last Friday at the dealer.
 

·
Registered
2008 chevy trailblazer_lt
Joined
·
2 Posts
Hi All
I just joined the forum and this is my first post.
The manifold crack on my 2008 Trailblazer last week.
Its going in to the dealership am 11/16. I usually work on the stuff myself, as over the year when I take something in to a dealership it comes back with more broke then fixed . And thats been my experience with this one too.

Took it in for and ignition problem ( it would start when the key hit the on position instead of turning to the start position ) got it back with the problem not fixed and a broken bezel around the switch .
The only reason its in the dealership I got a e-mail saying they had extended the warranty to cover this cracked manifold . But now I can't fined the e_mail.:duh:
Does anyone know where I can fined that bulletin ?
THX
Mike
Update, it's covered under warrenty. The manifold is on order at dealership. The mechanic that inspected it didn't have anything good to say about Trailblazer and pointed out a couple of problems that will be next. He has repaired several transfer case and halfshaft. He recomended not using the (Auto) on the transfer case it,s just a matter of time before you will be rebuilding the Tcase. By the way 11 hr. flatrate laber just to replace front diff 5$ gasket if it goes. This rig is going up for sale SOOON !!!!:mad:
 

·
Registered
2002 chevy trailblazer_ls
Joined
·
1,433 Posts
Glad the manifold is covered under the warranty. Weird that it went bad a second time :confused:

If you use A4WD all the time you'll wear the case out relatively quickly, but there are loads of people on here alone that have their original transfer case with high miles. Heck, I have nearly 150k on mine, original case, the previous owner didn't even change the fluid at the correct 50K mile intervals, and it works flawlessly in all modes. And the CV half shafts, yes, those can go bad, but that's the same with ANY vehicle. Again, I have nearly 150k on my truck and my driver side half shaft is still original. Passenger side has been replaced, but a brand new one only costs $60-75 or so and it is easy enough to replace. And the front diff gasket, yes it can go bad, but it isn't common for it to randomly go bad.

If you're getting all angry and ready to sell the truck over what 1 guy said, well, that's entirely up to you. I just think you're overreacting :no: :chillpill:
 

·
Registered
2003 chevy trailblazer_lt_ext
Joined
·
10 Posts
Broken Exhaust Manifold screw into Cylinder Head

I replaced the leaking Exhaust manifold for a friend of mine, saturday, on his 2003 Trailblazer , 4.2 I6... I had 4 of the 11 screws break. Two of them broke below the surface of the cylinder head. The other two had enough thread exposed that I easily welded a nut to them and screwed them out.

The two that were broken off below the surface... Were A LOT more work. But, I was eventually successful building up, the broken screw, with many tack welds to extend the broken stud to where I could weld a nut to it. I was being very careful not to damage the Cylinder Head. So several attempts resulted in twisting off the weld leaving me back where I started. But, after a while, a lot of patience, and perseverance, I did eventually get a weld to bite into the broken screw stud I was able to screw it out...

To make it a little easier to see into the hole. I did file the chamfer A LITTLE larger removing the first thread or so into the cylinder head. I did also attempt to drill them out using a 1/8 carbide drill in my 90deg die grinder... So, there was a small pilot hole for the weld to bite into (not sure it that helped or not)

I was using a Miller180 with Argon-75% and CO2-25% shielding gas using settings for welding 3/16" steel and stacking short small tack welds on top of each other... Then weld a hex nut to the exposed post...

I think this was a lot easier than removing the Cylinder Head... Or, even drilling them out...
 

·
Registered
2003 chevy trailblazer_ltz
Joined
·
193 Posts
Yes, I know this thread is fairly elderly. The existing photos are good, and I can add fresh info regarding the inexpensive Dorman replacement manifold kit. My 2003 Trailblazer was getting loud, and I could feel exhaust escaping from under the heat shield around the opening for the O2 sensor.

I got my replacement manifold kit from Amazon for $123 shipped to my home. It is packaged poorly.


The new exhaust donut was damaged in transit. The existing donut looked fine, I re-used it after bending the little tiny spring tabs that keep it secure in the exhaust manifold while the pipe is getting bolted-up. The Dorman-supplied donut doesn't even have these spring tabs.


The Dorman manifold is very similar--but not identical--to the original GM item. In general, the casting is of lesser detail and quality, all the GM foundry marks are MIA as I'd expect; and the machining is rougher.


Note the poor casting and rough machining. (It looks like the Chinese "machined" it by kicking it across a concrete floor.) The casting flaw doesn't actually matter as long as it doesn't promote cracking. The rough machining is a disappointment. If I had been better prepared, and with more time, I'd have had this Dorman manifold planed for straightness and surface finish. This manifold was about .006 out-of-true. It's borderline for acceptably flat, and probably rougher-than-acceptable to boot.





Even internally, the casting and the machining is not up to GM standards. The internal vanes are not shaped as nicely as GM; and the machining for the donut is missing the chamfer. Neither is a deal-breaker.


Another source of cost-cutting is the heat shield. The original GM shield has the inner layer trapped by the outer layer by folding the outer layer around the whole circumference of the inner layer, as seen on the lower shield. The Dorman shield has just a few tabs on the outer layer folded over to secure the inner, as seen on the upper shield. I also had problems getting the Dorman shield to clear the casting projections on the cylinder head above the two rows of bolts. Nothing some prying and bending with pliers couldn't fix--but I shouldn't have to.


While I'm peeved that the new manifold is .006 out-of-true, the old one is many times worse. You can see daylight between the bottom of the straightedge and the manifold at both the #1 and #6 (pictured) runner. I suspect that these manifolds move around a lot due to heat expansion, and eventually they warp and crack from the temperature changes. This also explains why all but one of the bolt-holes are so huge--so the manifold can slide back and forth under the bolt heads as it heats and cools.


Of course, of the eleven bolts holding the manifold to the head, only nine came out without breaking. Perhaps I'm lucky--others have had more broken bolts than I did. The broken bolts had nuts welded to them, and then they turned out. You can also see the Lang re-threading tap I used to assure that the holes in the head still had usable threads. This tap isn't long enough to go to the bottom of the holes--but it would thread in readily, and didn't pull any metal out. The threaded holes were just fine.


One bolt broke leaving about 1/4"--3/8" of stud sticking out of the casting. I turned a 5/16 nut onto those threads, welded the nut to the stud, and it turned out with some effort. The other bolt actually screwed out just as far, but broke flush with the casting--in the rearmost bolt hole, so it was moderately difficult to get at! I had to add weld material to the stud so I had something to hang the nut on. I welded almost a dozen 5/16 nuts to that stud, and they all broke off. I welded a 3/8 nut to it, and it held. Again, the bolt turned right out, but took a lot of torque to do so.








Original bolts are grade 9.8. I bought replacement bolts of a superior strength. The new bolts are probably as Chinese as the manifold, so there's no guarantee that they were made to spec. My local hardware store didn't have eleven of either kind, so I took all nine of the regular bolts, and added two flange-heads to make eleven. One potential problem if this ever has to come apart, is that the regular bolts use a 13mm socket, while the flange-head bolts use a 12mm socket. I hope I remember that a hundred-thousand miles from now! Each 35mm-long replacement bolt was just slightly longer than the originals, so I added a hardened ("Grade 8") 5/16 flat washer of sufficient thickness to make up the difference. The new bolts were all installed with Permatex copper-based anti-seize. GM specifies a thread-locking compound. The thread-locker will prevent the bolts from corroding, but the anti-seize should make removal easier since the bolts won't be locked in place. I torqued the manifold-to-head bolts to the GM spec of 15 ft/lbs. GM says to make three passes, each at 15 ft/lbs. I made a first pass at about 10 ft/lbs, and then three at 15. Before I put the heat-shield on, I ran the engine for ten minutes, let it cool and then made a final pass at 15 ft/lbs. Only a few of the bolts turned, and none turned very much.


The Dorman kit comes with exhaust pipe studs and steel nuts. I simply refuse to install steel nuts on exhaust flanges, so I bought two packages of studs and brass nuts just to get three metric brass nuts. Brass won't corrode to steel, so removal later is all but assured.


Other manifold replacement notes:

I really believe that the biggest reason the manifold bolt heads sometimes have popped off before even putting a wrench to them, is because the manifold moves around a lot due to expansion and contraction. As the manifold expands, it puts sideways pressure on the bolts, and I don't think the original bolts have acceptable fatigue strength.

All of my bolts still had the heads on them, and in fact even the ones that broke, didn't break until I'd turned them out about 1/4" or more. I think that if I'd used a swivel-socket so that no side-pressure went on the bolt from the excess force needed to turn them, that they might not have broken at all. SUPPORT YOUR RATCHET HEADS, don't let the ratchet or wrench push the bolt sideways as you turn them out.

Be sure to install the manifold gasket properly. The manifold has one hole that is just the size of the bolt. The gasket has one hole that is similarly small. Put the small hole in the gasket so it's aligned with the small hole in the manifold.

There's an air conditioning pipe-and-hose that goes across the engine. I held it up and somewhat out-of-the-way with a 4x4 chunk of lumber under the pipe, and on top of the engine plenum. It won't go much higher due to the way it's bolted to the air conditioning accumulator.

I removed the air cleaner and the windshield washer fluid reservoir. Easy enough to do, and it opens up a lot of area under the hood.

I used anti seize when I re-installed all the threaded hardware on this project, including the heat-shield studs and nuts, and the studs and nuts that secure the dipstick tubes. The heat-shield hardware seemed very weak. I did NOT torque the heat shield studs and nuts to the GM spec, because they got "rubbery" at about half the torque GM wanted. More cost-cutting by Dorman.

Short Story: The Dorman exhaust manifold kit has certain issues; poor machining being the most important. I have no idea how long the Dorman manifold may last. Maybe it's better than the GM manifold, maybe it's worse. On the other hand, considering how common this problem is; and how many of us have broken bolts in addition to cracked manifolds, even GM screwed the pooch--I can't recommend spending double or triple (or more) for Genuine GM parts in this situation since we know the GM failure rate is sky-high. The Dorman part is supposedly "Lifetime Warranty"; but that's for the parts--not the labor. When bolts break, the labor is the lion's share of the expense and headache.
 

·
Registered
2003 chevy trailblazer_ltz
Joined
·
193 Posts

·
Registered
2004 chevy trailblazer_ls
Joined
·
402 Posts
Yes, I know this thread is fairly elderly. The existing photos are good, and I can add fresh info regarding the inexpensive Dorman replacement manifold kit. My 2003 Trailblazer was getting loud, and I could feel exhaust escaping from under the heat shield around the opening for the O2 sensor.

I got my replacement manifold kit from Amazon for $123 shipped to my home. It is packaged poorly.


The new exhaust donut was damaged in transit. The existing donut looked fine, I re-used it after bending the little tiny spring tabs that keep it secure in the exhaust manifold while the pipe is getting bolted-up. The Dorman-supplied donut doesn't even have these spring tabs.

http://hbassociates.us/Trailblazer_Exhaust_Manifold_003.jpg[/IMG


The Dorman manifold is very similar--but not identical--to the original GM item. In general, the casting is of lesser detail and quality, all the GM foundry marks are MIA as I'd expect; and the machining is rougher.

[IMG]http://hbassociates.us/Trailblazer_Exhaust_Manifold_006.jpg
Note the poor casting and rough machining. (It looks like the Chinese "machined" it by kicking it across a concrete floor.) The casting flaw doesn't actually matter as long as it doesn't promote cracking. The rough machining is a disappointment. If I had been better prepared, and with more time, I'd have had this Dorman manifold planed for straightness and surface finish. This manifold was about .006 out-of-true. It's borderline for acceptably flat, and probably rougher-than-acceptable to boot.





Even internally, the casting and the machining is not up to GM standards. The internal vanes are not shaped as nicely as GM; and the machining for the donut is missing the chamfer. Neither is a deal-breaker.


Another source of cost-cutting is the heat shield. The original GM shield has the inner layer trapped by the outer layer by folding the outer layer around the whole circumference of the inner layer, as seen on the lower shield. The Dorman shield has just a few tabs on the outer layer folded over to secure the inner, as seen on the upper shield. I also had problems getting the Dorman shield to clear the casting projections on the cylinder head above the two rows of bolts. Nothing some prying and bending with pliers couldn't fix--but I shouldn't have to.


While I'm peeved that the new manifold is .006 out-of-true, the old one is many times worse. You can see daylight between the bottom of the straightedge and the manifold at both the #1 and #6 (pictured) runner. I suspect that these manifolds move around a lot due to heat expansion, and eventually they warp and crack from the temperature changes. This also explains why all but one of the bolt-holes are so huge--so the manifold can slide back and forth under the bolt heads as it heats and cools.


Of course, of the eleven bolts holding the manifold to the head, only nine came out without breaking. Perhaps I'm lucky--others have had more broken bolts than I did. The broken bolts had nuts welded to them, and then they turned out. You can also see the Lang re-threading tap I used to assure that the holes in the head still had usable threads. This tap isn't long enough to go to the bottom of the holes--but it would thread in readily, and didn't pull any metal out. The threaded holes were just fine.


One bolt broke leaving about 1/4"--3/8" of stud sticking out of the casting. I turned a 5/16 nut onto those threads, welded the nut to the stud, and it turned out with some effort. The other bolt actually screwed out just as far, but broke flush with the casting--in the rearmost bolt hole, so it was moderately difficult to get at! I had to add weld material to the stud so I had something to hang the nut on. I welded almost a dozen 5/16 nuts to that stud, and they all broke off. I welded a 3/8 nut to it, and it held. Again, the bolt turned right out, but took a lot of torque to do so.








Original bolts are grade 9.8. I bought replacement bolts of a superior strength. The new bolts are probably as Chinese as the manifold, so there's no guarantee that they were made to spec. My local hardware store didn't have eleven of either kind, so I took all nine of the regular bolts, and added two flange-heads to make eleven. One potential problem if this ever has to come apart, is that the regular bolts use a 13mm socket, while the flange-head bolts use a 12mm socket. I hope I remember that a hundred-thousand miles from now! Each 35mm-long replacement bolt was just slightly longer than the originals, so I added a hardened ("Grade 8") 5/16 flat washer of sufficient thickness to make up the difference. The new bolts were all installed with Permatex copper-based anti-seize. GM specifies a thread-locking compound. The thread-locker will prevent the bolts from corroding, but the anti-seize should make removal easier since the bolts won't be locked in place. I torqued the manifold-to-head bolts to the GM spec of 15 ft/lbs. GM says to make three passes, each at 15 ft/lbs. I made a first pass at about 10 ft/lbs, and then three at 15. Before I put the heat-shield on, I ran the engine for ten minutes, let it cool and then made a final pass at 15 ft/lbs. Only a few of the bolts turned, and none turned very much.


The Dorman kit comes with exhaust pipe studs and steel nuts. I simply refuse to install steel nuts on exhaust flanges, so I bought two packages of studs and brass nuts just to get three metric brass nuts. Brass won't corrode to steel, so removal later is all but assured.


Other manifold replacement notes:

I really believe that the biggest reason the manifold bolt heads sometimes have popped off before even putting a wrench to them, is because the manifold moves around a lot due to expansion and contraction. As the manifold expands, it puts sideways pressure on the bolts, and I don't think the original bolts have acceptable fatigue strength.

All of my bolts still had the heads on them, and in fact even the ones that broke, didn't break until I'd turned them out about 1/4" or more. I think that if I'd used a swivel-socket so that no side-pressure went on the bolt from the excess force needed to turn them, that they might not have broken at all. SUPPORT YOUR RATCHET HEADS, don't let the ratchet or wrench push the bolt sideways as you turn them out.

Be sure to install the manifold gasket properly. The manifold has one hole that is just the size of the bolt. The gasket has one hole that is similarly small. Put the small hole in the gasket so it's aligned with the small hole in the manifold.

There's an air conditioning pipe-and-hose that goes across the engine. I held it up and somewhat out-of-the-way with a 4x4 chunk of lumber under the pipe, and on top of the engine plenum. It won't go much higher due to the way it's bolted to the air conditioning accumulator.

I removed the air cleaner and the windshield washer fluid reservoir. Easy enough to do, and it opens up a lot of area under the hood.

I used anti seize when I re-installed all the threaded hardware on this project, including the heat-shield studs and nuts, and the studs and nuts that secure the dipstick tubes. The heat-shield hardware seemed very weak. I did NOT torque the heat shield studs and nuts to the GM spec, because they got "rubbery" at about half the torque GM wanted. More cost-cutting by Dorman.

Short Story: The Dorman exhaust manifold kit has certain issues; poor machining being the most important. I have no idea how long the Dorman manifold may last. Maybe it's better than the GM manifold, maybe it's worse. On the other hand, considering how common this problem is; and how many of us have broken bolts in addition to cracked manifolds, even GM screwed the pooch--I can't recommend spending double or triple (or more) for Genuine GM parts in this situation since we know the GM failure rate is sky-high. The Dorman part is supposedly "Lifetime Warranty"; but that's for the parts--not the labor. When bolts break, the labor is the lion's share of the expense and headache.


I just did the same job with the same results you had.
The only difference is I used the supplied exhaust donut and it leaked, although this may have been my fault (alignment on assembly). The collar won't pull the exhaust pipe up and seated when tightened.
Replaced it with the original donut (making sure it was seated before tightening the bolts) and alls well.
I did use the nuts supplied with the kit, now I'm thinking.....
 

·
Registered
2003 chevy trailblazer_ltz
Joined
·
193 Posts
The matching Dorman manifold-to-head bolt kit:
http://www.amazon.com/Dorman-03413B-...s=03413+Dorman

The larger photo shows them to be Grade 10.9, similar to the ones I bought. Less expensive, too. I'd have bought them, if I'd known they existed before I replaced my manifold.

Unlike the GM bolts, these appear to have no threadlocking compound.
 

·
Registered
2008 chevy trailblazer_ls
Joined
·
9 Posts
Trailblazer I6 cracked manifold

For what it's worth my 08 Trailblazer manifold cracked at around 45,000 miles. I took it to a local family owned auto repair. Cost $511.00 When I contacted the dealership I purchased it from they said send in the receipts and GM would reimburse. There is some type of extended repair warranty, not a recall but it covers the manifold for 10 years or 100,000 miles. Doesn't even have to be the original owner. I had a check from GM in 3 weeks. Good luck!
 
101 - 120 of 121 Posts
Top