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2.4 Exhaust Manifold Crack - do I even bother?

46K views 18 replies 12 participants last post by  laydeebugs.amc 
#1 ·
Tearing into my 2.4 ecocrap to replace the front catalytic converter. I discover the exhaust manifold is cracked in the familiar place, next to the 02 sensor. I can replace it now... do I even bother with it? It does not seem to be causing any problems and from what I see, the replacement will eventually crack as well.
 
#2 · (Edited)
If you have a small crack in your manifold now it probably will get worse.
For me it would depend on how long you are going to keep the vehicle.
If you plan to keep it for a couple of years, do it now while you are in there and be done with it.
My $0.02
 
#4 ·
If you leave it, it will get worse and you'll start sucking fumes in when the AC or heat is on.

Replace it with OEM not aftermarket and make sure it gets torqued properly when it's installed. You'll be fine for years.
 
#5 ·
What is with these exhaust manifolds cracking on the early terrain/equinoxs? Mine was also cracked at 89,000, and I've seen lots of people online with the crack in the exact same place. I wonder if the newer OEM manifolds are better built or is some sort of design flaw with the engine?
 
#7 · (Edited)
One thing you can do to help is take off the heat shield.
The reason the manifold is cracking in the same spot is the heat shield is holding the heat in close to the manifold.
The heat needs to radiate out and dissipate.
Think back to the old V-8's like the fat block 454 or 460, the manifold with the heat shield was always the side that cracked.


Then you will have to deal with the added heat in the engine compartment.
Will the extra heat be centered in a bad spot??
 
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#9 ·
I've been following this and other similar threads on the 2.4 cracked exhaust manifolds with some interest as my wife drives a 17 Nox LT with the 2.4 engine and I'm wondering if this is something I will have to deal with in the future. I've been wondering if this problem is exacerbated in the northern winter climes where you would have thermal expansion of the manifold and then a very rapid cooling during cold weather, especially if the car isn't garage kept. Would be interesting to hear from the folks that have had this problem, where they live, recent ambient air temps before they discovered the cracked manifold, garage kept or not, etc., at least it would be interesting to me, but maybe I over think things.
 
#10 ·
I like your approach. I'm all for collecting data and trying to piece together the puzzle, but given the failure history of these 2.4L Equinoxes and Terrains, graphed against the success history of exhaust manifolds in general, I'm willing to bet this is just another failure attributed to bad design and/or defective parts.

Is this something you will have to deal with in the future? The answer to that question would be very interesting to know, too, as it would tell us if GM did anything at all to rectify the problem for 8 years!

How many miles currently on your '17? And how long before you reach, say, 80,000 miles?
 
#11 ·
Colt, wife's Equinox currently has 11,000+ miles on it, purchased new in Feb. '17 so roughly about 10,000 miles/yr, not that many compared to others. Made the purchase of the 2.4 eyes wide open because I had researched the earlier 2.4 GDI oil consumption and timing chain issues thoroughly before making the purchase, but the wife had her heart set on a crossover and with the GM card earnings plus the incentives at time of purchase AND the fact that my wife is to cheap to buy anything other than 87 octane, the 2.4 it was. I however was unaware of the exhaust manifold cracks. Another thing that got me to wonder about the thermal expansion/rapid cooling of the cast iron exhaust manifold was that the Nox doesn't retain the underhood temperature anywhere near as long as the wife's previous DD, an 04 Bonneville SLE, but that had an iron block 3800 and you had iron block/iron exhaust manifold whereas with the 2.4 you have aluminum block/iron exhaust manifold. That make a difference? I suppose it's possible, but I have a 5.3 aluminum block Silverado and frequent those forums too and haven't seen any mention of exhaust manifold problems on that particular motor.
 
#12 ·
All the 2.4 exhaust manifolds are prone to cracking. My '09 Malibu 2.4 has a cracked one right now. Been cracked for a while also but at 173k it's gonna stay that way unless it gets too bad.
 
#14 ·
My father has an ‘08 Malibu. I’ll have to remember to check his when I’m home next. He bought it used as his 2nd car and it has 60,000+ miles on it. Gotta be cracked by now, right?
 
#15 ·
I had my manifold replaced at 90,000 miles, today 62,000 miles later and it is cracked again. I doubt that the dealership will be able to warranty the parts. I plan on buying after market this time. And maybe having the heat shield removed? Any other tips?
 
#16 ·
I wonder - if these things keep cracking in the same spot - if you could fortify that particular area with an added weld joint (??) prior to installation? Since I always drive my vehicles well over 200,000 miles, if I had this problem, that's what I'd be looking into.
 
#18 ·
In the Malibu group the 2.4 factory manifold or the only aftermarket one which is Dorman will crack sooner or later. I drove my 'bu over 100k miles with it cracked without any issues other than a wiff of exhaust once and a while when stopped idling.
 
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