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Cracked Exhaust Manifold?!?

17K views 25 replies 12 participants last post by  colemanw  
#1 ·
So, my 07 3.7 is turning 10 in August and I thought I'd take it to the dealership for a full fluid swap.. every last drop in the truck using synthetics where applicable. The dealership also preformed a general inspection and found two issues, my radiator is experiencing the beginnings of a leak (not yet dripping) which I expect is normal for a 10 year old radiator... What really has me burned is an exhaust manifold crack. And they say it's a $1500 fix! I expect an exhaust manifold to last the life of an engine.. My truck only has 44,500 miles on it and has been garaged and pampered since day one! Am I wrong thinking this is unacceptable? The nice lady at the service department agreed that it wasn't right and gave me contact info for the Upper GM people who I will call on Monday.. At the very least I would expect them to meet me part way and cover labor. School me if I'm out of my mind.

My big question to you fine 355 folk is what should I do about a radiator and exhaust manifold?

Should I go OEM (Why would I want another crappy manifold?)

Or are there higher quality replacement radiators and manifolds out there? I don't mind spending a little more for something that will do the job better and longer... but I don't need a crazy "cat delete high performance" manifold, just sturdy with maybe a little big better flow..?..

Any input is welcomed. Thanks!
 
#3 ·
Radiator -> get another OEM one and be done. BUT pictures of said possible leak. (NOTE) I've owned my truck since new in 2004 and I'm still on my original radiator and 116,378 miles strong

Exhaust Manifold -> poor design on GM's part. The drain for the AC drips on to the hot cast iron exhaust manifold. Hot + cold = cracks. I had a local shop weld mine up; its a special process to weld cast iron, but it only cost me $150. I removed the exhaust manifold and dropped it off at the shop; it only took them a couple hours
 
#16 ·
Cool, I'll order an OEM radiator.. wish the H3 two-core was a drop in part.. still haven't been able to find the leak with my own eyes yet...
 
#10 ·
This not only lists headers but a few manifold/header type pieces with cats as well. Covers all the bases and will definitely be cheaper than 1500 by far.
 
#7 · (Edited)
I think cracked manifold are common in this engine family. My 02 Envoy has a cracked manifold and that's the six-cylinder engine which the four- and five- cylinder Colorado/Canyon engines were based off. I found a non-OEM manifold on Amazon for $125, and was told online that it's about two hours shop labor. I'm just concerned about bolts breaking off in the head and driving up the cost of the repair. I'm not certain but I think the primary difference in price is that the Colorado/Canyon manifold has a catalytic converter combined with it while the Envoy doesn't, but don't quote me on that :)
 
#8 ·
What is the outcome on emissions and mixture control by using a cat delete header?
 
#11 ·
IIRC, I got a notice that I was covered for a cracked exhaust manifold until I hit something like 125,000 (exact number escapes me) for my 2009.

Too many minor recalls on the truck and car to keep track of them all.
 
#12 ·
Submitted my issue to GM yesterday. We shall see how it goes.

I like the header idea and read the thread that said you could do a cat delete header without screwing up emissions or the computer control systems. Is this in fact true? I don't want to be ending up with CEL lights and crap.
 
#13 ·
What year your truck is will change what you need to do in order to not have any CELs set but it is very simple to do for any year. Your secondary cat will clean up the rest.
 
#18 ·
I was just looking in the engine bay and couldn't see a second 02 sensor (maybe it is out of view underneath.)
 
#19 ·
it isn't too far after the first so you should have been able to see it. I believe the dual o2 sensor versions have one before the manifold cat and one after but the 07's i think were in between and still had only 1.
 
#20 ·
Well, GM gave me the middle finger. The dealership however stepped up in place and offered a reduced rate on parts and labor to the sum of a little over 400 bucks. I'm gonna take them up on the reduced labor but I think I'm gonna do an OBX header. Might weld and hold onto the old manifold too.

Wonder how much GM is going to loose the next time someone buys an F-150 instead of a Silverado because of my advice..
 
#22 ·
I was upset with mine, was extremely lucky the warranty was expiring in 9 DAYS!!! and was still covered. I have read of some do-it-yourselfers like me getting the OEM manifold and it being warped from the manufacturer, but still installing the part and pulling in the mating surfaces using the bolts. I would hope not too many people would use that as an option but the may be other circumstances. It seems headers are the way to go if you have to pay yourself.
 
#23 ·
Why pay the dealer to install the OBX header????

Its one of the easiest DIY mods out there...... unless you have more money then time :shrug:
 
#25 ·
I trust the mechanic at the dealer, I have been friends with the parts manager for a long time. I'm not so torqued that GM wouldn't do anything as I am that they designed such a crappy part. And yes, more money than time, and generally tools. My tool budgets over the years have been geared toward gunsmithing... not that a header requires much.. I don't even have a torq wrench though.. not to mention the finesse and nuance of experience.. I have seen some newbs do some pretty stupid shit to guns and I'd hate to do the same to the truck.