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2002 kia sportage
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Discussion Starter #1
Got a new one for you guys. About a year ago , when I bought the sporty, One of the first things to do on my fix it list was a cracked ex manifold.
Got a new code last week. P0422. Started checking and found the manifold cracked in half again.
First question- Would a bad cat cause this? Extreme heat?
2nd- How do I diagnose a cat problem?
3rd- If it is the cat, where do I get a CA legal replacement? Do I really need one

I work mostly on diesels and 2 stroke engines. I'm getting a little better with OBD engines, but I still need some pointers. Any help is appreciated. Thanks
 

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Caribou, Otter, Buffalo
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2,694 Posts
Most common causes of cracked manifold,

  • uneven torque,
  • non parallel mating surface,
  • hot/cold cycling,
  • Illegal air before CAT, causing rich burn.
...... Philip
 

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2000 Sportage 4x4 , 1998 Saturn SC2
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65 Posts
Where on the Ex Man did it crack ? Over Torque and Torqueing too much at a time will break it over time, I usually go thru the sequence in 7 steps to gradually bring it to spec in small increments.
 

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With the exhaust manifold off, you should be able to see the top of the ceramic honeycomb chamber in the pre-Cat easily.. If cracked or suspect, consider removing the front pipe @ the main Cat. converter & unbolting the pre-Cat. to physically inspect the condition of the ceramic chamber both top and bottom..

If the pre-Cat is damaged, consider unbolting the main Cat. and try to remove the ceramic material from the pre-Cat. -> that now resides in the main Cat. ..

* If issue started after a timing belt change, would recommend re-verifying static mechanical timing of the motor: if the timing is off even (1) or (2) notches on the Intake/Exhaust cams, the motor will still run, but will use extra fuel / and affect the life of any replacement Cat.

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*If you (reused) the double walled metallic gasket on the last exhaust manifold change, consider using a (new) gasket on this replacement.

*The front pipe should secured to the motor bracket / move as a unit - if the clamp is not present it will flex the front pipe and place torque on the exhaust manifold - make sure that clamp is present and bolted up..

If you have a lot of carbon in the ports where the exhaust manifold bolts up, consider using a dremel tool w/ wire wheel attachment to clean it up: if the head port casting is irregular (not uncommon), may want to consider using a fine stone attachment to smooth out the ports -> make them symmetrical ..

Regards,
GottaCruise
 

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2002 kia sportage
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Discussion Starter #5
Thanks for the replies. The manifold is cracked vertically, in between the 2 center ports. The flange up against the head is not cracked. Doesn't look like an uneven torque prob to me.
I did reuse the upper cat gasket last time, so maybe it was leaking pre-cat.
Inside of the upper cat doesn't look too terrible. I can see small chips around the outside edges, but its not torched or broken. Does it sound useable?

I do not see a clamp on the connecting pipe between the cats. I can see where they meet, and I can move it around. I knew it didn't look right, but thought it was a slip joint without a clamp. I'll have to find one this week.

Thanks again guys for the help. I'll check back to see what you think.
 

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Greetings Brian,

Without knowing the condition of the (entire) honeycomb in the pre-Cat, it is difficult for me to say if the condition of the pre-Cat is good or bad..

(If it was my ride), I would be verifying the condition of the pre-Cat by physical inspection, both top and bottom, given that the front pipe clamp was missing.

Here is a link to kiacarparts diagram of the correct install, item (4) front pipe clamp is what you probably need:

2002 KIA SPORTAGE Parts - Kia Car Parts has the Largest Inventory of Kia Parts in the USA!

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If you pull the (entire) pre-Cat., and front pipe off from the Main Cat., maybe you can direct a light source from the bottom of the front pipe far enough to visually verify the condition of the Pre-Cat chamber from the top, I dunno.

* I ended up unbolting the pre-Cat. from the front pipe, but I knew the honeycomb chamber on the '00 Sporty was bad when I had to do this: it was visibly cracked at the top, with the bottom half of the chamber in broken pieces, blocking the bottom pre-Cat outlet.

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This may be review, but hopefully these tips will help for a trouble-free install:

The mating surface on the block must be completely clean and free of material, this means getting the surface completely clean. I ended up using a mixture of PB Blaster, some WD40, and some Honing Oil, an extra-fine steel wool pad & alot of elbow grease :) to get it cleaned, then went over it with Carb cleaner & wiped down to remove any residue. ( *I did not use any 'mechanical' method of removal on the block, mainly because I did not trust having enough room to safely work w/o worrying about a mishap scoring the head. )

The mating surface of the exhaust manifold needs to be the same, but if you are installing a 'used' (yard-pull) exhaust manifold, chances are the mating surface has been 'impressioned' by the previous gasket: I ended up using the same mixture with a Dremel tool and fine wire wheel attachment to clean most of it up,

and ended up using the Dremel w/ fine conical stone & light touch to score up / smooth out remove the remainder of the surface to smooth.

The casting on the exhaust manifold ports seemed to be 'hit-or-miss', at least on the manifolds I pulled here..

For example, on the replacement manifold, there was an irregular piece of casting tailing in one corner that impeded about 3/8" of the cylinder #1 port on one side, it was definitely impeding exhaust flow.. :huh:

I ended up using the same Dremel tool w/ fine conical stone to remove the casting tailing(s) and 'smooth out' the ports here.

I also ended up doing some very minor porting on the exhaust side of the block to make sure everything matched up correctly, after using painters tape square up the ports, and putting a few extra layers on for good measure to prevent any accidental scoring of the mating surface.

Above took a full afternoon to get done, but turned out better than I hoped for, and has been issue free for a few years now.

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Another area to check is the manifold studs & nuts - if any are 'loose' or any thread issues, would recommend getting new replacement hardware to ensure a trouble-free install,

IIRC the toruqe spec. is (31) ft. lbs final, did the torque in several stages as cncman recommended above using a 'x' pattern from inside -> out, and slightly under-torqued to (30) ft. lbs here.

Hope this helps,
GottaCruise
 

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2002 kia sportage
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Discussion Starter #7
GottaCruise, Thanks for the info and parts link. Wish I found that site a while back.
Got it back together today. Inspected both cats, no sign of major trauma. Put new gaskets on the manifold and precat. I even stress relieved the manifold and did some clean up porting. Torqued everything to spec.

I'll let you guys know if anything happens in the near future. Thanks again for all the help
 

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Glad to hear the pre-Cat was ok and the site link helped - congrats on the repair,
GottaCruise
 
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