exhaust valve

[H3mainer]

my rig is in the shop have a sticking exhaust valve in the cylinder head requiring them to replace the cylinder head. anyone else have the problem. just to let you know my symtoms were rig a bit sluggish fuel economy went in the toilet like 12-14mpg and finally the engine light did go on. i didnt experience any stuttering or stalling that occurs sometimes with this problem. id be interested to hear if anyone else has had this problem

[HummerNewbie]

Sorry to hear about the troubles. Hope they get it fixed up real quick for you.

Originally posted by H3mainer:
...fuel economy went in the toilet like 12-14mpg...

In the toilet? That is what I am getting on a regular basis http://www.elcova.com/infopop/emoticons/icon_mad.gif

[lotus4s]

Originally posted by HummerNewbie:

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by H3mainer:
...fuel economy went in the toilet like 12-14mpg...

In the toilet? That is what I am getting on a regular basis http://www.elcova.com/infopop/emoticons/icon_mad.gif </div></BLOCKQUOTE>

Yeah, me too. I'd be smiling if I got 14. Must be a Florida thing... http://www.elcova.com/infopop/emoticons/icon_redface.gif

[HummerNewbie]

Originally posted by lotus4s:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by HummerNewbie:

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by H3mainer:
...fuel economy went in the toilet like 12-14mpg...

In the toilet? That is what I am getting on a regular basis http://www.elcova.com/infopop/emoticons/icon_mad.gif </div></BLOCKQUOTE>

Yeah, me too. I'd be smiling if I got 14. Must be a Florida thing... http://www.elcova.com/infopop/emoticons/icon_redface.gif </div></BLOCKQUOTE>

It's those damn FL speed bumps I tell you! http://www.elcova.com/infopop/emoticons/icon_razz.gif

[Av1ator]

It looks like they had a bad run of heads. I just had mine replaced.(In the shop a little over a month waiting for parts)
The Service Manager told they have had several H3'S with cylinder head problems. He also told the replacement head had a new part number meaning they had upgrading the head.

[Steve - SanJose]

Lowest I've seen is 14.2 mpg, highest 18 mpg. If my mpg starts dropping like a rock, I'll consider the head problem discussed.

S.

[f5fstop]

Have become aware of an Intake valve problem in cylinder one. Heads are sometimes are returned in whole at request of engineering for root cause analysis.
New cylinder head and all new valves are installed at the dealer. No statement about a new cylinder head part number, so I have to assume it is the same.
Sounds like this may be a quality spill at the cylinder head plant. A small number made it past testing and quality and go installed on th engine.
Condition will eventually cause a misfire, and a code P0300, tech does a leakdown test and determines the cylinder is bad.
It is NOT a bulletin, since so far, the numbers are low. This COULD change as vehicles get more miles.
That's all I could find out.

[Holliday]

Originally posted by f5fstop:
It is NOT a bulletin, since so far, the numbers are low.

It is for the Colorado/Canyon.
Been documented back to '04 models.
#04-06-04-081A (11/12/04) (http://www.coloradofans.com/viewtopic.php?p=98556)

[Av1ator]

No statement about a new cylinder head part number, so I have to assume it is the same.

I reported that the Service Manager told me that the cylinder head number had chanaged...I don't know it to be fact as I did not check the number myself..just reporting what the SM told me, I'll try to get more info on this.

[Av1ator]

TOTAL B.S. from the Service Manager. FStop is right they have not changed the part number. The one they installed on mine has the same part number as the one removed.

[f5fstop]

Originally posted by Holliday:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by f5fstop:
It is NOT a bulletin, since so far, the numbers are low.

It is for the Colorado/Canyon.
Been documented back to '04 models.
#04-06-04-081A (11/12/04) (http://www.coloradofans.com/viewtopic.php?p=98556) </div></BLOCKQUOTE>

I'll repost, "IT IS NOT A BULLETIN FOR THE H3."
I have access to all bulletins for any GM vehicle, and there is NO bulletin issued for the H3.
The problem the PI is looking at is the intake valve. Does not mean, that an exhaust valve can't go, it can go on any vehicle. But the numbers they are seeing at analysis is the intake valve, and it is still in the very low numbers.
Five or six on this site, tens of thousands on the road, make for a very small number at this time. If that number jumps, then an actual bulletin is processed and sent to dealers.
The p0300 misfire code can be set for many reason, bad valves, bad springs, warped head, bad injector, bad wiring, bad fuel, etc.
Examples of P0300 codes problems....
Subject: Info - Misfire DTCs P0300, P1380, P1381 and Catalytic Converter Damage Due to Installation of Alarm Systems #02-06-05-004b - (02/14/2006)
Models: 2006 and Prior GM Passenger Cars and Light Duty Trucks
2006 and Prior HUMMER H2, H3
2006 and Prior Isuzu Light Duty Trucks

Subject: P0300 Due to Random Misfires Not Felt - Possible Accessory Pulley - keywords belt CEL controls engine feel light MIL miss no SES #PIP3614A - (12/13/2005)
2006 Hummer H3
NOTE: The first one was an INFORMATIONAL bulletin, not a technical bulletin, the second was a PI.

[Holliday]

Originally posted by f5fstop:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Holliday:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by f5fstop:
It is NOT a bulletin, since so far, the numbers are low.

It is for the Colorado/Canyon.
Been documented back to '04 models.
#04-06-04-081A (11/12/04) (http://www.coloradofans.com/viewtopic.php?p=98556) </div></BLOCKQUOTE>

I'll repost, "IT IS NOT A BULLETIN FOR THE H3." </div></BLOCKQUOTE>

Nobody said it was. But the fact that GM hasn’t issued a TSB for the H3 doesn’t mean it’s not the problem described in TSB #04-06-04-081A. The I5 3500 is the same across the GMT355 platform and a TSB has been issued for the Colorado/Canyon for the very problem that the thread originator described. Since this issue has been documented on the ’04 & ‘05’s, it’s a safe bet that it will occur on the ’06 H3’s…being that it’s really an ’05-1/2. Having personally experienced the same symptoms as originally described in this thread on my Colorado, TSB #04-06-04-081A was applied and apparently solved the problem. However, there are more than a “few” reports of cylinder head replacements needed to solve the I5 valve train issues. BTW, the problem typically emerges around 12k to 18k miles. I haven’t seen any reports of this issue on the ’06 Colorado/Canyons as of yet, so maybe GM figures it will only occur in a few early H3’s and will quietly go away so they don’t have to issue an H3 TSB. My guess is that there’s been a random recurring problem in the I5 valve train, since there’s no VIN break referenced in the TSB and the problem has occurred across 2 MY’s.

Anyway, I believe it would be useful for an H3 owner that experiences these symptoms to mention to the dealer that a TSB covering the same symptoms has been issued for the Colorado/Canyon I5. It may save the problem from being misdiagnosed, since a Hummer/Caddy dealer probably wouldn’t check Chevy/GMC TSB’s to diagnose an H3 problem. That was my point.

Update: found some new info, break point is Build Date prior to 4/13/05...so that may include some early H3's.