Engine trouble: Cylinder one

[SDH3]

I did a search and read the other comments from Av1ator, pacey, etc., here's my story. First of all, let me preface this with I really love driving this truck, I usually alternate vehicles to break up the mileage for daily driving. However, I just realized I put 7K miles on the H3 in the past 3 months. OK, I'm 2 1/2 hours from home on a business trip, and the check engine light comes on. Called Onstar for a diagnostic, they said the engine is misfiring, and they told me to reduce speed, no rapid accelaration, and no inclines. Luckily, I was less than 10 miles from a Hummer dealer, and they said bring it on in, and in less than a half hour the tech had a read on it. He said the number one cylinder is bad, and the parts are on order and should have them in 5 days. No more details than that. When I get the repair ticket I'll post exactly what was done. They put me in a Caddy CTS and sent me on my way, that was Friday. This little caddy is fast, but a car just isn't the same. I'm standing by GM on this and believe it will go smooth.

[f5fstop]

Starting to see a few of these on this forum, at least three or four. Guess it is time for me to contact someone in engine engineering and see what the problem is; calibration or engine mechanical. (I'm nosy.)
I know in Feb, I ran the top 200 warranty hits, and engine was not there (other than engine re-calibrations). So at that time, it was not a problem; especially since number 200 was less than .5 IPTV (or close to that).
I am trying to figure out why parts take five days or longer? This engine is used in other applications and parts should be readably available.

[SDH3]

Thanks f5fstop! I'm curious too, and look forward to what you find out.

[Av1ator]

My dealer told me since they started working on mine they have had 'Several" in with the same problem.(Low Compression)

If you really get the parts in 5 days that will be great! However, it did take a month to get the parts for mine and it is still in the shop..The dealer told me and it was confirmed by the Hummer owners assistance line that the parts were backordered. Maybe the delivery problem is just in the Southeast??

[f5fstop]

Makes no difference where the parts are, they will be shipped, if available from another warehouse.
When you say low compression, what is the problem, valves, head, rings, pistons? I can run a check tomorrow, if I can get the time, to see what is available.
Then again, Black Tuesday is just around the corner, and who knows, I might not be a GM employee come Wed.

After working very closely with the Saturn assistance center in TN, as an engineering consultant (one of a three), not sure how customer assistance would check for parts. Most of them have no idea where the piston goes.
If mine was out for more than two weeks, I would hit them up for a complete new engine, head or short block, depending on what is actually wrong.

[Av1ator]

They are telling me the problem is with the valve seats. They are replacing my head with a new one.

As far as the new engine...I asked them to put a new engine in my H3..They said the ONLY WAY GM would replace the engine was if all attempts to fix my engine had failed..That was from the General Manager of the dealership..Are they telling the truth???

[f5fstop]

Wow, that long for a cylinder head? I'll have to check on that. I can't understand why it would take so long, this engine has been around for a while.
I wonder, if they had a production problem with some heads, and that could be the problem.
Only engine I know of that was replaced was at the dealer I purchased my H3 from, and it was due to an oil shop forgetting to install the oil pan plug, before sending the customer off on their merry way. Needless to say, they didn't get too far, and this replacement did not show up under warranty, since the oil change shop paid the bill. The SM told me it only took a few days for an engine.

[SDH3]

Well, it's been five business days, seven calendar days and no parts WTF!. Dealer says the parts are coming from the factory. What am I in a third world country with no overnight delivery? Starting to feel Av1ators dilemna. What's up GM? I'm trying to keep the faith.

[f5fstop]

I posted on the discussion forum, that GM is looking into this issue with the intake valve.
Could not get a confirmation, but I do know it is not at technical bulletin status, just a preliminary investigation, and no one would confirm, but after working in plant engineering, it sounds to me like a quality spill. In other words, X-numer of head made it past quality and testing, probably due to one of the milling machines not set-up properly.

[Planohummer]

For what it's worth, the head has been on intergalactic backorder for about 3 months. You can look at 2 possibilities:
1)Too many going into production
2)GM making damn sure replacement parts are good.

[SDH3]

Thanks for your input guys! I'm driving in the direction of the dealer today so I'll be making a pit stop.

[Pacey]

Well, SDH3 hope your case get's settled quickly. As for mine, after 7 weeks and a lot of fighting with the dealer he agreed to replace mine with a new one. He simply was unable to get the parts together. As far as I know, the car is still parked in a corner in the garage of my dealer - unrepaired. This whole case made be a bit uneasy about Hummer handling warranty claims but I simply could not find an alternative car for me Anyway I'm cruising now for a month with my new baby and so far everything goes well. I have to admit though that I have not gone on the freeway yet and have kept him below 55mph for now 600 miles. So I think the engine should be broken in by now. I've to hit the freeway this weekend,so let's see...

[SDH3]

Good News!, it's done, and 13 days total, but damn it felt like a month. I can't pick it up for a couple of days, but when I do I'll post the repair.

[Jim Williams]

Hi Folks, Same problem here at 9k miles. Cylinder # 1 low compression, dealer takes weeks to get parts, full head, intake valves, lifters, springs, gaskets, etc. It now has foul odor when parked in the garage. Got it back from Weseloh Hummer, Carlsbad today, they can't find source of the burning rubber smell. They said 3 others with same failed engine problem, what gives?

[f5fstop]

Not sure why the dealers are saying there are "x-number" of other vehicle waiting for cylinder heads. It seems like everyone who has had problems with the heads make this type of statement, and with the number of reported replacements, I'm having a problem believing the dealers.
There is a problem happening with some of the cylinder heads (valves), and parts are hard to come by at this time due to the supplier. However, as of last Monday, there were only 157 cylinder heads replaced out of approximately 35K H3's produced.
For some reason, Colorado/Canyons do not have as many replaced, but that could be it is an optional engine on that truck.
GM is looking at the problem very seriously, but at this time, there is no root cause for these valves to fail.
Supplier is in the process of booting up production, and to produce a full head assembly for replacement. At this time, the head is bare, and the dealer has to build it up with valves, springs, retainers, etc.
I can tell you this, to replace a cylinder head on the I-5 is about a two day process. The oil pan must be removed to remove the front cover, which means the front axle has to be moved, and I believe on the H3 the steering gear has to be removed too.
Won't help those with parts on order at this time, but in the future, parts will be more readily available in the future.

[SDH3]

The REPAIR: Scan for codes P0300 - Missfire graph shows no. 1 cylinder missfire - Perform compression test no. 1 has 175 psi, and nos. 2-5 has 225 psi - Perform leak down test on no. 1 cyl. - 20% leak down on no. 1 cyl. at 100 psi leaking through intake intake valves.
Replace cyl. head, replace all valves, replace all valve springs, reinstall cyl. head, test drive.
The PARTs: One Head # 88984229, Ten Valves # 24576974, Ten Valves # 24576975, Ten springs # 12596078, Gasket # 88984219, and various bolts, seal, coolant, oil.
I have driven 1k plus miles since the repair, and took it off road to see if there would be any rough idle, hesitation, or stalling at these lower speeds and conditions, and NO PROBLEMS so far, so good, running very smooth. The problem and repair is pretty much the way f5fstop described it in these engine problem posts. BTW f5fstop, the dealer and I had a total miscommunication and everything is OK!, Cool.