I have a 2008 H3 Alpha with 109,000 miles. I love my Hummer, it will be painful if I have to sell it. I was at 92K miles when ran out of oil while driving. I drove the car (while was knocking) for about 30 miles. I had gotten an oil change and the place messed up the oil change. YES, It was not smart to drive when the engine was knocking but I'll blame that part on the fact I'm a woman and had NO idea what that noise was.

There were NO immediate problems after the oil issue. At 102K my transmission went out (completely). I put in a new transmission ($2400) and the engine light went on at 106K. The code is P0430 and the dealer said I need a new catalytic converter the total cost would be $3000. So, I took my Hummer to a mechanic that had good reviews. At the end of the day, he told me that it would be a huge pain to put a new catalytic converter in because the location was too difficult. He said, he wouldn't even want to do it but if he did it would be 6 hours labor and like $5K. I live in Southern California and I will need to smog my car eventually.

Did I really do major damage that just didnt show up right away? Does anyone think my Hummer will need new pistons? I don't want to get rid of my Hummer but at 109K, how many more miles can it get if I spend the money? If it was YOU what would you do?

 

The catalytic converter(s) on the 5.3 V8 ARE a pain. There's 2, and they bolt up directly to the manifold, and on the Tahoe are actually part of a one piece Y shaped assembly. I replaced them on my wife's '06 Tahoe a while back (maybe 2 years). I called around to find the part (was going to install myself). Found a good price at a dealership in Riverside, CA of $900 for the part. I then called my local dealership (Banning, CA) to see if what they would charge me for install. They said $135, AND they would also match the price on the part if I bought it from them. So, $1100 later, it was done.

Call around for the part (California, has to be OEM, aftermarket is not legal), and THEN call around to see how much a dealer will install it for (labor only). A quick google search (right side 258444505, left side 25982292) shows about $600-$700 each (right and left), and my parts manual shows 1.7 hours labor per side. Based on that, you should be able to get them both replaced for under $2000 if you're willing to do a little leg work.

 

How did you know what side you needed?

 

On my Tahoe, it didn't matter; they were both part of a 1-piece unit, so they both had to be replaced even though only one had gone bad (the material inside broke up and was clogging the exhaust and rattling around). Since the H3 has 2 individual units, you could actually replace only one, for about half the price I posted above. However, the P0430 code is for the catalytic converter "bank 2", and I don't know which side bank 2 refers to. Maybe someone else on here knows? The other thing to consider is that if one is bad, the other is probably getting ready to fail also since they are both the same age and have been subject to the exact same conditions.

 

Call Tustin Buick, GMC. Ask for Mike Sabarrese. They used to be a great Hummer dealer and still service them. Mike works on H1s only but will make sure you get treated fairly. Tell him David M referred you.
The 5.3 is a pretty hardy motor. While you didn't do your engine any favors if it is running fine now your are probably ok. I would address the issue with the oil change place. The chains basically all suck. If you don't have someone that can do it for you go to a dealership. They usually aren't much more and you can make an appointment so you don't wait long.

 

Do you think I would need new pistons as a result of the driving without oil? Can they check that since the engine will be apart?

 

Not nearly enough info to answer your question, but if you did run it dry, and scored the cylinder walls and toasted the rings, then yeah it could. New pistons is an oversimplification, as you have to pull the motor and rebuild it to hone out to oversize the bore to remove the "scratches" and install larger dia. pistons and rings.

No, they cannot check your pistons when doing exhaust work, replacing CATs does not require taking the engine apart.

It may not if you are not having issues now and it does not burn oil?

 

Actually, the Alpha has Three, two mini cats (Pup Cats) in the Y Pipes (2 piece) directly off the exhaust Manifolds, and a third Cat in the exhaust behind the Y Pipe. The third Cat is not monitored. Yes, they are a PITA.

 

OK, so it's at the dealership. They gave me a price breakdown. I got them to do the Catalytic Converter for $1100 (per 650Hawks price). New spark plugs and wires $500 (seems high), new front brakes and pads $275, and the "clunking" noise was because it needed new transfer case bolts $80. It's going to take 4 days because they cant get the cat converter for 2 days.

 

Way to negotiate, except for the plugs and wires. $500 is ridiculous; what are they installing, gold plated plug wires?