This is a 4.3 motor, 6 cylinder, 290k+ miles. I had this blazer since 2002 if I recall right. I was planning on getting me another vehicle but I had settled down in just maintain this one since what I want will require a loan and I am not interested in payments. Anyway, I started today working on some stuff and would like to hear options about he other stuff and I rather not start a thread for each item up until I get to the point that I really need help or stuck. I dont expect anyone to react to each item but if you are inclined to respond to one item that will be great. I want to take this puppy and have it run for another 200k miles...

1. Bank 1&2 lean.
This is the problem I worked on today. I got me the Torque app a year or so ago and every time im in the highway and going over 55 my injectors will be wide open (25%LTFT, both banks). This would give me the OBD11 code 171 and 174. I smoked the top end for vacuum leaks, replace multiple sensors, got an oem fuel pump and fuel regulator (fuel pressure was not spec and was fixed by that) to no avail. Lastly, I replace the injectors assembly today with very good results. No more 25%LTFT, in roads that I have extensively test and I knew every time will show 25%LTFT. Worst it did was 21.something and it just momentary. It stays mostly in the 18 if I going uphill and fluctuates from 10 to 17 in other conditions. BTW, all these parts are use parts from the local Pull-a-parts. I know the parts are not optimum but I was looking to see if I saw an improvement when changing a part which will point me in the right direction. Now, when i had the lean condition I was running around 16 to 17 mpg, today Torque showed me to be doing 17.4. I was expecting to see a larger improvement. I know I still have stuff to do, change spark plugs, new spark plugs cables, new 02 sensors and many other things to improve the MPG but am I expecting too much to see this go to 23 MPG?

2. Transmission - 4L60-E (I think...)
Last time I was here I had a transmission problem and end up getting it rebuilt. I had my first transmission rebuilt a bit over 100k miles, second around 200k miles but since then It seems the car last about 2 years then the transmission needs rebuild. I will have to say that for the last 4 to 5 years this vehicle has been used only to haul stuff like my boat, camper and trailers. The boating hauling was usually sort drives and a not too big boat. The camping is the long drives, usually to the mountains of NC or TN but there are only 3 to 5 trips a year. The heaviest load is the camper which is nowhere close to 3k so I never thought of adding a transmission cooler. Looking at my transmission temp I have come to realize that I will need a transmission soon. The temps during regular driving is around the 200 deg f, when hauling is between 215 deg f in flat and up to 250 deg f climbing. This is way past the normal 160 range... I am changing the radiator and will add the extra cooler but seems I am destined for a transmission change. This time I will go to pull-a-part and get one there. It wont be more than $100 bucks.
Any of you have rebuild a transmission? I see the video and it really did not seem too bad. I do all my mechanic work except the transmission. Not sure if I should get the kit which seem to be under $300 and do it myself... Any input on those that has done it will be great. BTW, I do weld so I can fab most brackets and "tools" that are not complicated...

3. Radiator
Not much on that, it is leaking at the top aluminum section. Will do the transmission cooler when I pull the old radiator off. Should I install the cooler in the line that comes from the transmission or the line that leaves the radiator?

4. AC vacuum lines.

When I try to select the mode for the face, feet, windshield it never changes. I have mostly the air coming on the top vents to my face. A bit to the windshield and none to my feet. If I select the max ac I can hear the actuator by the blower closing. Last time I checked at the firewall I had a leak on the vacuum line towards the ac controls but did not check any further. I wonder if there is any prone part that I need to look at instead of starting troubleshooting the entire inside vacuum system. That would save me some time.

5. Shock absorbers
They just need changing too. These are the OEM.

More misc fixes...

6. Driver door Alignment.
I have replace those pins and bushings before but it broke in a few more years as the hinge is a little deformed where the pins wore the hinge. I can probably do some welding and drilling to return that part to normal unless there is another way like oversize bushings or so. Im sure I am not the only one, actually, I seen many blazers in the junk yard with the same problem.

7. Hatch back glass
I press the button and the glass wont release. I have not look into this but is that an electronic button or is this a mechanic latch?

8. 4x4 sometimes get stuck
I had a faulty 4x4 switch, that was fixed but my 4x4 gets stuck every now and then. Generally I just drive a bit and i can hear a clank and the 4x4 releases, sometimes shutting the blazer does it. I did took the vacuum actuator out one time and cleaned it. That solved the problem for years. Is that what I need to do, just mantain it or could it need a new actuator? I assume the 4x4 is engaged when there is vacuum applied to the actuator, is that correct?

9. If after I get all these other stuff down I might end up doing an engine overhaul. I am sure that after 4 or 5 years of that lean problem those valves are not in the best condition but I am not looking forward to take that motor out. Can I overhauls this motor in place? I know if I do that I wont be able to take the crankshaft out, but at least the valves would be worked and I can hone the cylinders and put new rings... Not sure yet if I will go with the trouble... just putting it out there to get feedback on those that have done the job...

Thanks for your input...

 

Transmission: needs to have fluid, (DexronVI) filter & gasket replaced every 36k miles. When you drop the pan, about half of the fluid remains in the transmission, that's why the low change interval is necessary. Flushing the transmission is not recommended.

When transmission fluid temperature consistently exceeds ~200F, it will destroy the trans rapidly. If you tow ANYTHING, it needs a cooler installed. Imperial 243012 fits perfectly, with minimal mounting bracket fabrication. If you use that cooler, and totally bypass the OEM cooler in the radiator, it will maintain transmission fluid temperature ~60F above ambient temperature.




These things alone, will improve transmission performance and longevity.

 

I have rebuilt a few of these and they are not that difficult. I taught myself with a $20 manual and time. The high temps cause the oil performance to go down and result in transmission failure.
Bare-bones tools required are a set of picks, some transmission snap ring pliars, basic hand tools, Vasoline, and some DIY stuff for compressing springs(all-thread, nuts, flat steel and various lengths of large exhaust pipe). I can't find my picture of all the tools I have made so I might have to snap another picture next time I have them all out. It's not much and most of it came out of a scrap bin and then I either had to bend or drill holes. Certain transmissions require different sizes based on the diameter of drums but I have rebuilt a few 4L60e and 4T60e so far.
If you have at least 24 hours total and a 4x8' work area you can get a basic rebuild done for under $300 including a few performance parts.

 

Thanks both of you for your responses.
I am starting a new thread just for the transmission
https://blazerforum.com/forum/engine...-needed-88713/
TZF, which manual was that?