How to evaluate a used '99-06 1500 for purchasing... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

bradleyheathhays · 12-26-2025, 06:42 AM

Hey everybody. I'm about to purchase my first truck (so happy), and I need to get some advice on what kind of mechanical inspection I should go through before handing over my $$$. Keeping my eye on a number of listings, but my first choice is a '06 Sierra with the 4.8L, auto trans, and 140k miles. I know to crawl over the entire thing looking for leaks and rust (I'm only searching in the South and West to avoid rust altogether), as well as jacking the wheels up to push on the wheel at 12 and 6, and 3 and 9 to look for play. Check cylinder compression for sure...but what else? Thanks.

Greg58 · 12-26-2025, 07:30 PM

I trust the seat of the pants feel. Ride, steering, brakes. Check for unusual engine sounds, power should be smooth, trans needs to shift smoothly. Roll down the windows and listen for noises from the wheels, driveshaft, rear end, etc. Many noises will change with steering input, on or off throttle. You are smart to avoid the rust belt, I have bought several trucks from Texas to avoid rust.
Greg

Accelo · 12-26-2025, 08:11 PM

Confirm the cab heater and defrost are working correctly. It's A known issue on these trucks. The whole dash has to be removed to change out the cores, and it's expensive.

**70cst** · 12-27-2025, 11:45 AM

Some of this will be repeat...

Double check the frame for deep rust ... I think the frame is the weak link in these trucks.

As been said ... if its got power windows - door locks - check them out good. Any lights lit on the dash?

Check Fenders and rockers for hidden rust.

AC working well.

Car-Fax

Best wishes for you.

LS short box · 12-28-2025, 06:44 PM

Keep in mind the years you are looking at may have spent a bunch of years up in the rust belt.
I always recommend taking the truck to a mechanical/body shop and have it inspected by the pros.
Be really wary of new paint and drive train work that don't have the receipts to back up the work.

67swb72klb · 12-28-2025, 09:39 PM

Give a good look at the rockers that seems to be one of the first to rust along with above the rear wheel openings..

**WorldsCrappiestTruck** · 12-29-2025, 12:29 AM

Check to see if there are any broken off exhaust manifold bolts. Very common. Repair is a hassle, but not a showstopper. I have done many, all by welding to the broken bolt and eventually backing it out, but it is a pretty terrible job when they are broken off below the height of the aluminum head.

Accelo · 12-30-2025, 01:29 AM

Purchase a west coast truck. I have never seen one with rusting issues. I have owned the same Silverado for over 20 years. The original seats were really bad. I updated the radio to aftermarket so I have a back up camera and hands off phone abilities. I also replaced the seat with one from a newer Silverado. My truck may be worth more than I paid for it.. Been a great truck.

EVRLET · 12-30-2025, 02:03 AM

Dash clusters are swapped on these all the time for low mileage readings. Mileage is stored in the cluster, not the pcm.

If you don’t run a carfax, you risk paying top dollar for what you think is low mileage but a 250k+ junk.

Also like past C10s, parts are swapped from various years. Learn how to read VINs and RPO codes

12-26-2025, 06:42 AM	#1
bradleyheathhays Registered User Join Date: Aug 2017 Location: Lexington, Ky Posts: 54	How to evaluate a used '99-06 1500 for purchasing... Hey everybody. I'm about to purchase my first truck (so happy), and I need to get some advice on what kind of mechanical inspection I should go through before handing over my $$$. Keeping my eye on a number of listings, but my first choice is a '06 Sierra with the 4.8L, auto trans, and 140k miles. I know to crawl over the entire thing looking for leaks and rust (I'm only searching in the South and West to avoid rust altogether), as well as jacking the wheels up to push on the wheel at 12 and 6, and 3 and 9 to look for play. Check cylinder compression for sure...but what else? Thanks. __________________ 'If the end of the world ever comes move to Kentucky, because everything there happens 20 years later.' ~ Mark Twain

12-26-2025, 07:30 PM	#2
Greg58 Registered User Join Date: Jan 2017 Location: Valley, NE. Posts: 1,064	Re: How to evaluate a used '99-06 1500 for purchasing... I trust the seat of the pants feel. Ride, steering, brakes. Check for unusual engine sounds, power should be smooth, trans needs to shift smoothly. Roll down the windows and listen for noises from the wheels, driveshaft, rear end, etc. Many noises will change with steering input, on or off throttle. You are smart to avoid the rust belt, I have bought several trucks from Texas to avoid rust. Greg __________________ ________________ 1970 GMC Sierra Grande, 2500 133" wb, 402, 4spd. 2007 GMC 3500 SRW 4x4, Crew cab, Duramax/Allison. (Sold} 1987 Chevy Suburban 2500, Silverado, 2wd, 454, t-400 2023 Chevy Silverado LT 3500, crew cab, longbox, 4x4 Z-71 Duramax.

12-26-2025, 08:11 PM	#3
Accelo Registered User Join Date: Mar 2015 Location: washington Posts: 2,426	Re: How to evaluate a used '99-06 1500 for purchasing... Confirm the cab heater and defrost are working correctly. It's A known issue on these trucks. The whole dash has to be removed to change out the cores, and it's expensive.

12-27-2025, 11:45 AM	#4
70cst Senior Member Join Date: Feb 2001 Location: New Madison, Ohio Posts: 21,400	Re: How to evaluate a used '99-06 1500 for purchasing... Some of this will be repeat... Double check the frame for deep rust ... I think the frame is the weak link in these trucks. As been said ... if its got power windows - door locks - check them out good. Any lights lit on the dash? Check Fenders and rockers for hidden rust. AC working well. Car-Fax Best wishes for you. __________________ A husband can be right...or...A husband can be happy. 67-72 Chevy and GMC Trucks...The Classic Truck for the Classic Folk. 1970 CST Two tone green, 402BB, 400 Automatic, Tach, Buckets, AC, AM-FM, Tilt, GM CB, GM 8 Tract, LWB, etc JOHN 17:3...The better side of "LIFE" Remember: Everyday is a good day...Some are just gooder!

12-28-2025, 06:44 PM	#5
LS short box Registered User Join Date: Jun 2015 Location: Carlos MN Posts: 2,591	Re: How to evaluate a used '99-06 1500 for purchasing... Keep in mind the years you are looking at may have spent a bunch of years up in the rust belt. I always recommend taking the truck to a mechanical/body shop and have it inspected by the pros. Be really wary of new paint and drive train work that don't have the receipts to back up the work.

12-28-2025, 09:39 PM	#6
67swb72klb Registered User Join Date: Dec 2010 Location: livingston co.mi Posts: 2,559	Re: How to evaluate a used '99-06 1500 for purchasing... Give a good look at the rockers that seems to be one of the first to rust along with above the rear wheel openings.. __________________ California 65 GTO---Texas 64 burb 283 ---Oklahoma 67 CST SWB BBW wood bed 327 2004r---New Mexico 72 k10 350 350 auto---Georga 72 short step project

12-29-2025, 12:29 AM	#7
WorldsCrappiestTruck Senior Member Join Date: Mar 2022 Location: Hinesburg Vermont Posts: 350	Re: How to evaluate a used '99-06 1500 for purchasing... Check to see if there are any broken off exhaust manifold bolts. Very common. Repair is a hassle, but not a showstopper. I have done many, all by welding to the broken bolt and eventually backing it out, but it is a pretty terrible job when they are broken off below the height of the aluminum head.

12-30-2025, 01:29 AM	#8
Accelo Registered User Join Date: Mar 2015 Location: washington Posts: 2,426	Re: How to evaluate a used '99-06 1500 for purchasing... Purchase a west coast truck. I have never seen one with rusting issues. I have owned the same Silverado for over 20 years. The original seats were really bad. I updated the radio to aftermarket so I have a back up camera and hands off phone abilities. I also replaced the seat with one from a newer Silverado. My truck may be worth more than I paid for it.. Been a great truck.

12-30-2025, 02:03 AM	#9
EVRLET Registered User Join Date: Aug 2015 Location: Las Vegas NV Posts: 380	Re: How to evaluate a used '99-06 1500 for purchasing... Dash clusters are swapped on these all the time for low mileage readings. Mileage is stored in the cluster, not the pcm. If you don’t run a carfax, you risk paying top dollar for what you think is low mileage but a 250k+ junk. Also like past C10s, parts are swapped from various years. Learn how to read VINs and RPO codes __________________ Customization is what you want it to look like -- not what other people think it should look like



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