I just bought a 07 suburban ltz 5.3l with 84k miles. I'm reading all the horror stories about the engines and transmissions. I am having a tough time enjoying my new car, I wanted one so bad and now that I got it I'm very worried about it, any advise or info to help ease my mind or did I step in poop by buying this car.
Thank you guys in advanced

 

Why are you worried? Are you having problems? Enjoy the vehicle. Most are great vehicles with little or no problems. If they have been well cared for, you can have a trouble free vehicle for 300,000 miles or so. Enjoy it while it is running good and don't worry about anything until something does happen. I take care of mine. Change the oil regularly and don't drive like a mad man and get trouble free service out of my vehicles.

 

As an original and still current owner of a 2007 Yukon XL that has about 80k miles, I understand where you are coming from. I love my Yukon, but am concerned about the common issues that seem to come up, most notably oil consumption and lifter failures. I have had the oil consumption issue, and solved it using the approach below. As a side note, I have been towing an 8,000lb loaded travel trailer since new and have not had a single transmission issue. It is been a completely reliable ride during the time I have had it, just regular maintenance outside of this oil consumption issue.

If working well you are off to a good start, but I would still recommend a few things.
- turn off AFM. This can be done by using the Range Delete plugin (which I use, works great) or by getting a tune. I have not seen any noticeable change in mpg, and have seen lots of benefit in throttle response and engine braking, plus reduced oil consumption.
- get a catch can. This will stop the motor from ingesting all the gunk from the PCV. See my posts around pg 15 on the GM Active Fuel Management Woes thread.
- keep the oil clean. The AFM lifters run on oil pressure, any sludge buildup can lead to failure. Consider an oil additive to flush the sludge.
- keep the top end clean. Use Techron or similar in the gas to clean the valves, pistons and combustion chamber in general.
- let the engine run. Our trucks are low mileage for the year, probably a lot of short runs. Try to give it a good run every so often if this is the case.

Here is what I think happens. I think AFM starts a cycle where oil gums up the rings causing blowby. The blowby causes excess vapors in the PCV which end up getting ingested back into the intake, causing further buildup on the valves, pistons and rings. If not caught, the rings deteriorate and cylinder walls get damaged. And it just keeps getting worse unchecked. The 3 or 4 things I did seemed to take care of the problem, hopefully it helps the engine stay healthy for several more years.

The other thing is that although there are some common issues, there are posts where folks have 200k+ trouble free miles with these years. So, not every one will fail. Consider my suggestions, sit back and enjoy a great machine.

Congrats on your Suburban! I hope this helps!

 

I had the lifter/cam issue on my 07 Tahoe back at 35k miles. Had the lifters and cam replaced and had the AFM turned off when i got it tuned by Black Bear. I'm at 170k miles now and keep all my fluids clean. Trouble free!!! Enjoy it.

 

The 5.3ltr is a great engine. To put your mind at ease I would flush the engine and run synthetic 5-30 oil, do a complete fluid change on all components and run full synthetic products in everything. Differential, transmission, radiator, make sure there is no metal in anything and stay on top of the maintenance. You will love the car.