2002 Chevrolet Trailblazer i6 4.2L

[LotI]

Originally Posted By: mrdctaylor
12 quarts just for the radiator? Or is that for the whole cooling system? I've got a couple of other cars and their rads both hold less than 2 gallons (8 qts).

13.9 qts for the cooling system with the 4.2L I6

 

[mrdctaylor]

Hmmm. So does anyone happen to know how much I'll get out if I just drain the radiator? I want to be sure to have enough on-hand. I bought 2 gallons of 50/50 but I can't seem to find this info anywhere.

 

[DriveHard]

there are two available diffs. on the trailblazers if I remember right. The "posi" rear end is what is driving the special requirement on the fluid. If you have the special option, I would use the special fluid. IF you have a normal "open" diff, then proceed with previous random suggestions.

The electronic fan clutch is a known "wear item" that usually needs replacing around 100K. The fan will default to fully "on" and roar with the engine...decreasing mileage and increasing warm up time.

Thermostat as previously mentioned also common failure point, as well as the cam sensor.

If you have hesitation or poor part throttle driveability than clean the throttle body - this has solved many woe's in the past, and is dead simple to do.

I had mine tuned by PCMforless. MUCH improved driving experience, and if I ever have another trailblazer this will be the first thing I do again.

 

[Falcon_LS]

1. I see you live in Texas - the very first thing I would do is get a decent transmission cooler in there to complement the cooler in the radiator. Take it from someone living in an equally hot climate - we're in the high 110's here right now and my TFT is hovering in the 210-235 F range.

I got an ACDelco cooler for another application, which I will be installing very soon. This is something I didn't realize until my torque converter started to shudder bad and I finally got around to installing a ScanGauge-II. I've got a Derale transmission pan there as well, with an additional 2 quart capacity and cooling fins. Perfect fit.

I would advise you check the condition of the ATF, and if it's decent, either do a line off flush with a quality Dexron-VI, or a partial drain and refill until all the fluid is replaced. I personally put in 2 bottles of LubeGard Red in there as well, which works well.

2 . For engine oil, I personally favor synthetics. My export vehicle calls for ACEA A3 instead of ILSAC GF-4, I run a low SAPS 5w30 with a WIX XP filter. Mobil 1 0W-40 would be a decent option, perhaps 5w30 EP or GC 0w30 if you can get it. If you're using an ACDelco filter, get the PF-61 instead of the PF-61E.

3. Replace the thermostat and thoroughly flush/back flush the cooling system with Dex-Cool. Toyota SLL pink is a decent alternative if you want to switch, as is John Deere CoolGard-II.

4. Replace the hydraulic brake hoses for safety reasons, if they've never been replaced. DOT 4 fluid works well in this application. You may need a Tech-II or equalivant to bleed the ABS module.

5. I run Autolite double plats, many people swear by ACDelco 41-103's (NGK). Either way, I would do the plugs and get a set of coil boots/springs. Denso has a well priced, good quality offering.

6. With the engine off, pull the power steering cooler line off and turn the wheel to full lock from the side to side to get all the fluid out. You can run GM power steering fluid or an alternative - I use CHF 11S.

7. Diff fluid. The gasket's reusable, unless torn. I like using the grape scented GM 75W-90 stuff (part # 89021677).

8. The valve actuator solenoid and cam position sensor are two things to look at.

Check your ball joints, especially the uppers, brake pads/rotors and make sure the fan clutch is in good shape. Use a pressure washer to clean out any dust/debris in the AC condenser/radiator.

 

[mrdctaylor]

And what if the fluid is NOT in decent shape? I just checked it and it looks dark. It doesn't smell burnt, but it doesn't look red either. I know my parents never did any towing in this vehicle, but it has 150K miles (I may have stated that the mileage was lower earlier). People on a Trailblazer forum have recommended against changing the ATF at this point. Would you agree with that? I just want to extend the life of this vehicle--not cause issues quicker.

 

[Falcon_LS]

If it doesn't smell burnt, chances are it's still alright. Might want to use a hand pump to pull a small sample out the dipstick tube and get it analyzed would be a safe option. Usually I pull out 2 quarts and add 2 quarts to see what kind of difference it would make, if any. If there's an improvement, I go ahead and replace the fluid. it's a gamble, but not changing the fluid isn't going to help much either.

 

[mrdctaylor]

I guess I'm just having a hard time deciding whether I will be extending the life of the transmission by replacing some of the fluid, or if I'm going to lead to a quick failure. :-/

I know it is my call. I've just heard so many horror stories of transmissions that weren't touched for their life and then the new owner replaces the fluid and it fails almost immediately. :-(

 

[ChrisD46]

Falcon_LS : Quick question (sorry) In my '02 Trailblazer LTZ I tried to pump out the ATF through the fill hole with a inexpensive Harbor fluid Freight hand pump and only got out approx. 1.5 qrts before it started burping air ...Any tricks you know to get more ATF out of the fill hole on a Trailblazer ??

 

[LotI]

Originally Posted By: ChrisD46
Falcon_LS : Quick question (sorry) In my '02 Trailblazer LTZ I tried to pump out the ATF through the fill hole with a inexpensive Harbor fluid Freight hand pump and only got out approx. 1.5 qrts before it started burping air ...Any tricks you know to get more ATF out of the fill hole on a Trailblazer ??

Not Falcon_LS but a little help from an owner...You probably have the deep pan and the dipstick doesn't reach to the deepest part. The deep pan has a step down towards the rear of the vehicle.

The easiest way to drain the fluid is the cooler line on the passenger side of the vehicle. Disconnect the line to the cooler to a large pail and start the truck. When bubbles start to appear shut it off and refill. Repeat as necessary to get the old fluid out of the TC. The pan holds 5 qts. The whole system takes 9-12 qts. If you don't feel comfortable doing this, because you might starve the pump and therefore the bearings, just pump out 2 qts then fill and repeat. A helper is great for this. There are many how-to's out there for this procedure.

I will note that I changed the fluid in my Rainier first time at 122k miles and it's worth pulling the pan. The magnet was pretty furry. I used the cooler line to drain the pan of most of the fluid then pulled the pan. I didn't spill oil all over since I wasn't dealing with a pan full of oil. I also changed the filter but didn't change the seal since mine was still pliable.

 

[Falcon_LS]

Originally Posted By: LotI
Originally Posted By: ChrisD46
Falcon_LS : Quick question (sorry) In my '02 Trailblazer LTZ I tried to pump out the ATF through the fill hole with a inexpensive Harbor fluid Freight hand pump and only got out approx. 1.5 qrts before it started burping air ...Any tricks you know to get more ATF out of the fill hole on a Trailblazer ??

Not Falcon_LS but a little help from an owner...You probably have the deep pan and the dipstick doesn't reach to the deepest part. The deep pan has a step down towards the rear of the vehicle.

The easiest way to drain the fluid is the cooler line on the passenger side of the vehicle. Disconnect the line to the cooler to a large pail and start the truck. When bubbles start to appear shut it off and refill. Repeat as necessary to get the old fluid out of the TC. The pan holds 5 qts. The whole system takes 9-12 qts. If you don't feel comfortable doing this, because you might starve the pump and therefore the bearings, just pump out 2 qts then fill and repeat. A helper is great for this. There are many how-to's out there for this procedure.

I will note that I changed the fluid in my Rainier first time at 122k miles and it's worth pulling the pan. The magnet was pretty furry. I used the cooler line to drain the pan of most of the fluid then pulled the pan. I didn't spill oil all over since I wasn't dealing with a pan full of oil. I also changed the filter but didn't change the seal since mine was still pliable.


I second Lotl.

I first replaced all the fluid in my transmission at 56,000 miles - this was the first time the transmission was ever touched and I wanted to get all the Dexron III out to replace with Dexron-VI. I used an old, marked 5L oil container to flush out 3L at a time and went through 20 liters of fluid.

Originally Posted By: mrdctaylor
I guess I'm just having a hard time deciding whether I will be extending the life of the transmission by replacing some of the fluid, or if I'm going to lead to a quick failure. :-/

I know it is my call. I've just heard so many horror stories of transmissions that weren't touched for their life and then the new owner replaces the fluid and it fails almost immediately. :-(


Maybe someone else will chime in on this, but what does the fluid on the dipstick look like if you lay it down on some paper towels?

 

[mrdctaylor]

Quote:
Maybe someone else will chime in on this, but what does the fluid on the dipstick look like if you lay it down on some paper towels?


At 152K miles, mine looks dark but it doesn't smell burnt. I'll try to snap a photo soon.

 

[ChrisD46]

LOTl and Falcon_LS : Thank you so much for the replies ! When I first bought the used '02 Trailblazer my mechanic dropped the ATF pan , drained , changed the filter and then re-filled with 5 ~ 6 qrts. of Dexron VI . Knowing only roughly half of the ATF was changed with this method I wanted to find an easier way to remove the remaining ATF (I hope the original poster can learn from this as well...Also new Dexron VI is cherry red - if dipstick fluid is brown colored then consider it old).

 

[mrdctaylor]

Originally Posted By: ChrisD46
LOTl and Falcon_LS : Thank you so much for the replies ! When I first bought the used '02 Trailblazer my mechanic dropped the ATF pan , drained , changed the filter and then re-filled with 5 ~ 6 qrts. of Dexron VI . Knowing only roughly half of the ATF was changed with this method I wanted to find an easier way to remove the remaining ATF (I hope the original poster can learn from this as well...Also new Dexron VI is cherry red - if dipstick fluid is brown colored then consider it old).


How many miles on it when you changed the ATF for the first time?

 

[Oil Changer]

None of the above will matter if you're not 100% positive she won't drink/text and drive. Good luck and best wishes.