H3 Bad cylinder head ;(

[SC_Hummer_Guy]

I rolled in on my 50K warranty with 49999 on the truck I actually called them and told them I might go over but I wanted it covered! Haha now that's cutting it close.

 

[poncho1965]

and Last 6 of VIN Less than 287591...........

Not sure how I missed this thread, but my VIN is 163***, no worries since I only have 35k on my H3?

 

[06 H3]

mine was 108XXX I was way under that #...

 

[alrock]

Poncho, plenty of trucks outside that VIN range have had head issues, including mine. Just keep an eye on your truck and don't ignore the CELs that come up. I think think in those trucks in the problem VIN range many head issues appeared early. For other trucks, they've just appeared whenever, including with much higher mileage on the odometer.

 

[atvspeed4]

My light has come on and off for a while. They said they are not allowed to do the work unless the light stays on constantly and when they clear it, it comes right back on. I was on my way back from vacation yesterday and my fuel economy dropped off, the light came on and I still do not think they will fix it.

 

[alrock]

Have them run a compression test. It sounds like bull on the CEL. I had a bad head for a long time and the CEL would come on for about a day, disappear for a while, and come back.

My dealer didn't worry about codes staying on. The kept it overnight, ran compression tests on warm and cold engines, and then replaced the head. My guess is the CEL policy belongs to the dealer and not GM.

 

[H32NV]

It is in the dealer as of today with 99640 miles. lol. had to take it camping just once more this weekend.

 

[alrock]

Good luck!

 

[Dennis]

I rolled in on my 50K warranty with 49999 on the truck I actually called them and told them I might go over but I wanted it covered! Haha now that's cutting it close.

You lucked out on that one...You should've played the Lottery that day too..:thumbs:

 

[atvspeed4]

Have them run a compression test. It sounds like bull on the CEL. I had a bad head for a long time and the CEL would come on for about a day, disappear for a while, and come back.

My dealer didn't worry about codes staying on. The kept it overnight, ran compression tests on warm and cold engines, and then replaced the head. My guess is the CEL policy belongs to the dealer and not GM.

They ran the compression test and said that there was a slight leak by but not enough to warrant the work.

 

[06 H3]

I've searched far and wide and can't find the Vin #s for the H3s with this problem. Does anyone have it?

 

[f5moab]

I believe it is 287591 and older....

 

[H32NV]

cylinder 3 misfire detected today, started idling rough and about five minutes later threw the code. really hoping its the coil and not this, but the way ive been going through oil lately(and never see smoke?) its got me wondering.....

Back when I had the compression check earlier in the year, everything checked out at the dealer, and they said a leak-down was good as well.

at 115k now.

 

[Bigunit]

OWow, H32NV where and how the hell have you been? Talk about random posts! I'm beginning to feel used and abused. Glad to see you're back and still around. Moab this April?

Sent from my XT1080 using Tapataint

 

[H32NV]

I'm hoping so. its my dirty thirty. We know how to throw a party right?

 

[Bigunit]

You got that right! I'll bring some good Scotch for you!

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[Zach]

If it is a bad head. Push GM on it. They may do a participation on it, but you won't pay the full replacement cost.

 

[H32NV]

So i replaced all the plugs with OEM ACDelco Iridium type, moved the coil from cylinder 3 to cylinder 4, and vsvsa. Problem code went from P0303 to P0304 - so it followed the coil. Put a new coil in it, drove for a few days perfectly. Now I've got P0304 again. Plugs in general looked pretty good, they had about 50k on them, and were Bosch Pt/Ir Fusion plugs, which they have since discontinued, or so im told. Suspect of this, I put OEM's back in it. Cyl 3 plug had a ::hint:: of brown on it indicating water. All other plugs looked normal with no excessive ash, carbon, oil, or brown deposits. Ran a compression check, all cylinders 110psi within 3psi of each other.

So Now I'm going to pull the new coil and maybe swap it with cylinder 1, and see if the new coil was just a dud and went bad right away.

 

[Bigunit]

Interested to hear what you find out.

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[06 H3]

Hope it's not the head. If its not dont take no for an answer when it comes to the bull**** of a dealer

 

[H32NV]

well, changed the coils around, and put the new one on cyl 1. noticed that some of the wire loom on the ignition harness had been cracking, probably due to heat cycles, and so i replaced all of that and sealed the ends with electrical tape. fired right up and purrs even better now. I noticed quite a bit of wear on the top of the motor, on the rail where all of those individual coil wires come out of the main harness, 5 locations total. Looked like maybe some arc'ing had been going on near cylinder 4. So I doubled up the loom and electrical tape in those locations, put it all back together, and now we'll see in the next few days if the symptoms come back....

 

[alrock]

Fingers crossed!

 

[H32NV]

P0304 is back, although its slightly less noticeable than before. New coil is now on cyl #1, so thats probably not it. Thinking its an injector($25 on RockAuto), Cam Sensor(intake or exhaust, $13-24), or the crank sensor. The only last thing it could be is the cam shaft actuator, or its finally a bad head. for $60, im throwing darts in the dark! Whos with me!?

 

[H32NV]

UPDATE: Ordered new Exhaust Cam Sensor, Intake Cam Sensor and Crank Sensor from RockAuto. Installed both Cam Sensors, and right away the idle RPM went from 680 nominal to 740. (ScanguageII). engine sounds super smooth.

UPDATE2: Installed new Crank sensor, old one was covered in copious amounts of oil?? main seal leak?

 

[alrock]

Glad update1 worked for you. Can't offer any input on update2.