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Discussion Starter · #1 ·
Greetings all. I have a 2007 TB LS 6cyl, 4wd, 93K. So far I have replaced both front wheel bearings, added a tranny cooler and electric brake controller, (I tow a 1600lb Aliner camper), new ignition switch and am getting ready to replace plugs and coils, and already cleaned throttle body due to low rpm code. Previous owner took good care of her, did all scheduled maintenance (had all receipts) until I bought her with 68K a year ago. Serp belt is good, no cracks, all hoses in good shape. As I am on a fixed income, I was hoping my fellow TB owners could give me some insight on what I should focus on. Thanks all for any help.
 

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Well, one of the most important maintenance items is the oil and filter change. At the very minimum, follow the Oil Life Monitor that is "built into" your TrailBlazer or do an annual oil change. Now, to save a few bucks, I would recommend that you go to Walmart and purchase their SuperTech Full synthetic 5W30 motor oil along with something like the Fram Ultra oil filter.

Walmart's SuperTech Full Synthetic motor oil is a premium full synthetic motor oil, and it meets all the latest oil specifications. The same ones that Mobil One, Pennzoil Platinum, and Valvoline meet.

The next thing I would add to the list is to change the transmission fluid and filter, and then change it every 2 to 3 years or 30000 miles since you tow. Use Dexron VI and you should not have any troubles.

Not knowing where you live, I seriously suggest you look at the power steering lines and see how rusted they are. The best place to check them is on top of the driver's side strut tower. If they are corroded, plan on changing them in the near future. If you can change them yourself, great! The job is a royal pain in the @$$, but is doable for the DIY-er. If you have to pay to have it done, expect it to cost somewhere between $500 - $1000 for labor because they are so difficult to do.

The antifreeze needs to be changed every 5 years or 100,000 miles, and you can use Dex-Cool without any problems. Yes, there are a lot of horror stories out there about Dex-Cool, but the vast majority of them are due to people not properly maintaining their cooling system, or in GM vehicles from the late 1990s through early 2000s where GM cheaped out and used intake gaskets that had polymer sealing areas that were incompatible with Dex-Cool. That was an engineering mistake for not testing the chemical compatibility of the polymer with the Dex-Cool. Replacement intake manifold gaskets went to a different sealing material and the were no more problems with them leaking.

Now for any parts you might be needing for repairs or maintenance, I would say stay away from ebay as there as a ton of counterfeit parts being sold there. If you purchase parts on Amazon, make sure the seller and the shipper are both Amazon if possible, or at the very least, the fulfillment part is Amazon. That way you have some recourse if you get a bad part. If possible, get your parts from rockauto.com for those repairs and maintenance items you can plan for.

When it comes to purchasing parts, stay away from the low cost, no name white box generic parts that have prices too good to be true. They are typically junk. Stick with established brands such as ACDelco, Delphi, Standard Motor Products (non T series), Standard Blue Streak, BWD (non P series), and Denso as an example.

Have fun and good luck!
 

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Nearing 100K on the odometer means the ignition should be serviced. That doesn't necessarily mean the coils need to be replaced, however. Clean and test, and if they are intact replace only the plugs, silicone grease the coil boots, and put them back in service. Since yours is a 4.2L I-6, look for oil pooled in the spark plug wells and deal with that if necessary.

100K is also a good time to perform the cooling system flush/refill.. If it were mine, I would stick with the original DexCool. There are a lot of reasons, but I'll spare you the Mary Shelly novel (for now).

Other frequently overlooked items are draining (as much as possible) and replacing power steering fluid, and flushing brake fluid. Both of those have a finite life, and don't age as well as wine or good scotch. It may only cost you a quart of each fluid to do the job.

Drive axles are also something to be serviced, and if it is AWD/4WD the transfer case should get fresh Auto-Trak II oil.

If you catch all of those items as routine maintenance, it only costs you fluids. If not, it may start costing hard parts.

Then there is body maintenance, which is one of the most commonly overlooked items, even in dealer service departments. Hinge. latch, and door detent cleaning and lubrication (Tri-Flow or superlube oil only), lock cylinder lubrication (dry graphite), cleaning and application of silicone grease to door, hatch, and cowl seals and window sweeps, rubber treatment for body mounts and suspension bushings and snubbers (JTM #8 lube is great for this), spare tire hoist cleaning and lubrication, driveshaft/CV lubrication, and other items in the shop service manual which are not in the owner's manual.
 

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Discussion Starter · #4 ·
Well, one of the most important maintenance items is the oil and filter change. At the very minimum, follow the Oil Life Monitor that is "built into" your TrailBlazer or do an annual oil change. Now, to save a few bucks, I would recommend that you go to Walmart and purchase their SuperTech Full synthetic 5W30 motor oil along with something like the Fram Ultra oil filter.

Walmart's SuperTech Full Synthetic motor oil is a premium full synthetic motor oil, and it meets all the latest oil specifications. The same ones that Mobil One, Pennzoil Platinum, and Valvoline meet.

The next thing I would add to the list is to change the transmission fluid and filter, and then change it every 2 to 3 years or 30000 miles since you tow. Use Dexron VI and you should not have any troubles.

Not knowing where you live, I seriously suggest you look at the power steering lines and see how rusted they are. The best place to check them is on top of the driver's side strut tower. If they are corroded, plan on changing them in the near future. If you can change them yourself, great! The job is a royal pain in the @$$, but is doable for the DIY-er. If you have to pay to have it done, expect it to cost somewhere between $500 - $1000 for labor because they are so difficult to do.

The antifreeze needs to be changed every 5 years or 100,000 miles, and you can use Dex-Cool without any problems. Yes, there are a lot of horror stories out there about Dex-Cool, but the vast majority of them are due to people not properly maintaining their cooling system, or in GM vehicles from the late 1990s through early 2000s where GM cheaped out and used intake gaskets that had polymer sealing areas that were incompatible with Dex-Cool. That was an engineering mistake for not testing the chemical compatibility of the polymer with the Dex-Cool. Replacement intake manifold gaskets went to a different sealing material and the were no more problems with them leaking.

Now for any parts you might be needing for repairs or maintenance, I would say stay away from ebay as there as a ton of counterfeit parts being sold there. If you purchase parts on Amazon, make sure the seller and the shipper are both Amazon if possible, or at the very least, the fulfillment part is Amazon. That way you have some recourse if you get a bad part. If possible, get your parts from rockauto.com for those repairs and maintenance items you can plan for.

When it comes to purchasing parts, stay away from the low cost, no name white box generic parts that have prices too good to be true. They are typically junk. Stick with established brands such as ACDelco, Delphi, Standard Motor Products (non T series), Standard Blue Streak, BWD (non P series), and Denso as an example.

Have fun and good luck!
Thanks for all the help. When she hit 75K I started using Castrol GTX high mileage. I change it every 4K. I only buy AC Delco from AutoZone. I don't trust parts from Amazon, heard too many horror stories!! As for PS lines, they appear in good shape, but as she was in New England most of her life( in Oklahoma for last 4 months) there is some rust, but nothing too bad as it was always garaged and well maintained. I guess my biggest concerns are front end issues, i.e. ball joints, tie rods, etc. Are there sensors I should be worried about due to age? Thanks again for all your excellent advice. It helps more than you know, and will save me $$. 👍
 

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Are there sensors I should be worried about due to age?
One that seems to cause problems is the oil pressure sensor. It can fail and leak oil back through the electrical connector, causing an oil spot on the driveway. It's easy to change. It's located right above the oil filter, at least on the wife's '06 TB with the I6 engine, so it should be in the same spot on yours. I don't know if you do your own oil changes, but when you have the filter off you can see it right there. If you don't have a flex head ratchet, this is a good reason to get one, as a regular ratchet won't fit in there too well. IIRC, the size for the socket is 1-1/16". That's the size of the Duralast 1/2" drive socket I have that's oily, so I think that's the one I used. Next time you're at AutoZone grab one. It has a blue band around the top. It's shorter than most other sockets that size, which helps.
With the filter off, remove the electrical connector, then slip the socket over the sensor. NOW put the ratchet on the socket. Give the sensor 1/4 turn to break it loose, then remove the tools. Now you can reach up there and unscrew it by hand. Put the new one in, snug it up by hand, then give a 1/4 turn with the socket and ratchet. Put the electrical connector back on. Done. This adds maybe 5 minutes to an oil change. There are YouTube videos of people removing the right front tire and trying to snake their hand and socket in through a tiny opening in the wheel well. Don't do it that way! It's more work than it has to be!
The "oil pressure gauge" on these trucks isn't really a pressure gauge. It's more of a glorified idiot light. If you have anything above minimum pressure, it will tell you you have 40 pounds of oil pressure. If you don't, a warning light comes on. The pressure sensor is really not much more than an on/off switch.
Sorry for the babble-fest, but I hope this helps.
 

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One that seems to cause problems is the oil pressure sensor.
Too add to what flyboy has said, I would also recommend spraying some electric safe degreaser on the connector its usually coated in oil. I used CRC 05103 QD Electronic Cleaner. If you have access to Amazon.com you can get Lisle 13250 Oil Pressure Switch Socket for around $7, its an exact fit for the sensor. Takes all of 10 minutes to replace it, I just removed the skid plate (4 bolts IIRC) and you can access it above the oil filter.
 

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The other sensor (actually sensors) I would be the front ABS/Wheel Speed Sensors. Rust/dirt/grime has a tendency to form/collect between the bottom of the sensor and the trigger wheel on the wheel hub assembly. When this happens you can get slow speed ABS activation when braking under any condition, or error codes. You just remove the sensor from the wheel hub assembly and clean the hole out, clean the bottom of the sensor off, and then clean the mounting surface off so the sensor goes in all the way to the proper depth.

One last thing to check for cleanliness is the camshaft position sensor connector and the connector and socket to the Variable Valve Timing Solenoid. Make sure the connectors and the sockets are clean. If the sockets on the sensor/solenoid are oily, they might be leaking and that is an indication to change them in my book.
 

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Discussion Starter · #9 ·
I did replace both speed sensors when new front wheel bearings installed. Weird thing now though... sometimes when it's damp out, if I back up from a cold start, then go forward the ABS/speed sensor lights come on. Shut it off, restart, lights gone. Weird 🤔 Any thoughts?
 

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Check the ABS connectors and make sure they are seated properly
 

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Health care Fluid Medicine Service Plastic bottle







For an Affordable & Quality Oil And Filter I Get the Havoline Syn Blend 6 qt bag in a box from Walmart and 12 / Pro-tec Oil Filters individually wrapped From RockAuto
Oil + filter just under $21 per oil change assuming you use 6-1/2 quarts as mine reads full on dipstick with that amount
I had been using the Ac Delco filters prior in it when it was new but noticed they stopped making the PF-61 metal core style and use the "E" core type which i feel is not as good Imo
Been using the USA made Pro-tec in other Applications for years and they are under the same umbrella as Wix but this filter is Made in Mexico but looks fine to me
They are a Metal core filter so i will be using it on my 4.2 w / Pro-tec on my next change very soon
 

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2002 Pewter ls with automatic trans. 4x2, gray cloth interior.
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wow 93k miles! I use pennzoil ultra platinum @ $24 with a Wix XP filter @ $11
Not only is Ultra platinum same price as mobil 1, it works a hell lot better than mobil 1. Trust me I tested it on my Corvette for 2 years and I drive 140 on it too. Now that's well worth it to me.
 

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Discussion Starter · #13 ·
Quick side question regarding oil change.. Has anyone ever used STP Ceramic Oil Treatment? Just curious to see if these type of additives are worth it. Thanks y'all 👍
 

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2002 Pewter ls with automatic trans. 4x2, gray cloth interior.
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Quick side question regarding oil change.. Has anyone ever used STP Ceramic Oil Treatment? Just curious to see if these type of additives are worth it. Thanks y'all 👍
I think that came out a few months ago but I never tried it. However I've used restore oil treatment on the trailblazer. I picked up my Trailblazer in Jan of 2020 and with 197k miles. After 2 weeks I did an oil change and added restore oil treatment and I did notice a difference.

You can't go wrong with STP, They're one of the oldest brands out there. I've recently tried Marvels mystery oil, can't really speak much on though. Restore sure did it's thing, but I don't know if the previous owners every did any oil treatments.
 

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I'd like to try STP Pro-Series Intake Valve Cleaner. I've heard great things about that and especially from a gear head.
 
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