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Ok, so here are specs. '03 envoy, 4.2, 61,500 miles. I just cleaned the TB two days ago, coolant recovery tank was empty, filled to cold, 34% oil life left, always maintained. Brand new tires on all sides. Never had any, flushes, tranny, rad, for the first time i poured gumount fuel injector cleaner when i filled up. Im thinking i need a new fan clutch due to excessive roar noise sometimes when i start and head off. Not everytime, but fairly loud and last about 2 mins. Also, my coolant gauge is 2 clicks away from 210. I just added coolant to the tank, but it still seems at 210. I got the p0128 code so i added antifreeze, hoping it's not the thermostat. Anymore ideas what I can do to gain back my hp, as well as acceleration? Oh, I almost forgot, im only getting 16-16.2 mpg city. Thanks!
 

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2003 chevy trailblazer_ls
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youll have to figure out why your reservoir was low.
there may be a leak somewhere..if air got into you cooling system- then when you replace the thermostat--- try to remove all the dexcool and refill with 50/50 mix.

dexcool and air dont mix. it forms crud...that can cause overheating in the future (if in large quantities).

so get the thermo fixed 1st... then that may increase your mileage...
since youre always running cool-- it decreased mileage a bit/
 

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2002 olds bravada
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youll have to figure out why your reservoir was low.
there may be a leak somewhere..if air got into you cooling system- then when you replace the thermostat--- try to remove all the dexcool and refill with 50/50 mix.

dexcool and air dont mix. it forms crud...that can cause overheating in the future (if in large quantities).

so get the thermo fixed 1st... then that may increase your mileage...
since youre always running cool-- it decreased mileage a bit/
:iagree: X10. When you run cooler than you should, the PCM will adjust the shifting points and RPM ranges. The engine is literally dumping more fuel into engine, trying to get it running at the temp its suppose to. Basically it will rob a horsepower/performance and MPGs. 16 MPG city is very decent, but will most likely see improvements in highway mileage.
 

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2005 chevy trailblazer_ls_ext
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Im thinking i need a new fan clutch due to excessive roar noise sometimes when i start and head off. Not everytime, but fairly loud and last about 2 mins.
I'm not so sure I'd worry about - when it roars all the time is when you should worry.
Also, my coolant gauge is 2 clicks away from 210. I just added coolant to the tank, but it still seems at 210. I got the p0128 code so i added antifreeze, hoping it's not the thermostat. Anymore ideas what I can do to gain back my hp, as well as acceleration? Oh, I almost forgot, im only getting 16-16.2 mpg city. Thanks!
I'm assuming by 2 click away from 210 you mean to the left of 210? That along with the P0128 code is definitely a bad thermostat.
"This means that the engine's PCM detected that the engine has not reached the required temperature level within a specified amount of time after starting the engine. The intent of the P0128 code is to indicate a faulty thermostat."
http://www.obd-codes.com/p0128

And as wardak33 said 16 MPG for city driving isn't bad at all. Some of us rarely see that. I've seen as low as 11 -12 (in the wintertime in heavy stop and go driving). The original EPA estimate for my 05 EXT was 15 for city, but I think they since revised it to 14.

I would check your water pump for leakage. The water pump on the I6 engine is NOT it's strong point.
 

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2006 chevy trailblazer_ls
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Help with your TB

Some of us "more mature" members remember the 4.3 Chevrolet engine, especially in the Blazer and the Astro van. These engines always made more noise than usual, it sounded like they were going a lot faster than they were.

The first thing I would check would be if the clutch fan is in fact releasing. Or not engaging at all. Poor fan activity would result in higher coolant temperatures.

Lost coolant can be significant, but don't go looking for trouble. Check your rad cap, coolant recovery lines, and the radiator first. Then do the compression check.

Tobruk
 

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Discussion Starter · #6 ·
i dont know what or how to check ''coolant recovery lines, and the radiator first. Then do the compression check.''
So about the fan clutch, i heard if its more than 2 mins then the clutch is going out, i seen one on ebay for 67.00 compared to 159.00 or 199.00. So what other measures to atleas improve sluggish starts when driving?:thx
 

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2003 chevy trailblazer_lt
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I am having a similar problem. Only real difference is that mine is all the time. I just changed the fan clutch (Dorman from Rock Auto) water pump and belt. I have 99,968 miles. Temp is just under 210 most of the time if not always.Loud ROAR on moderate acceleration at 3,000 rpm and or 30-40 mph. Any ideas would be very appreciated.:thx
 

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i dont know what or how to check ''coolant recovery lines, and the radiator first. Then do the compression check.''
So about the fan clutch, i heard if its more than 2 mins then the clutch is going out, i seen one on ebay for 67.00 compared to 159.00 or 199.00. So what other measures to atleas improve sluggish starts when driving?:thx
A 67.00 fan clutch is on the cheap side, and I would not want to go through the trouble doing it 2-3 times. Get a good one from one of the vendors on this site, 125-150 if I remember right. OK, if you do replace the fan clutch you are money ahead to also do the water pump, t-stat, hoses, Dex-Cool+distilled water and serpentine belt. The coolant recovery line is that smaller hose on the top of the rad. that goes to the left and on to the tank. I would put a hose clamp on it if there is not one already, and I doubt if it has a clamp on it. After doing all this when you refill and restart the first time you shut it down and it cools do not be surprised if the coolant tank goes dry, it is just being sucked to the rad. and engine due to air pockets after being drained. Just refill with dex-cool and distilled water. You might need a reflash of the PCM after the fan replacement. Someone else here will advise you about this.
 

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Check this out!

:)I have a 2004 Trailblazer with 84,000 miles. I have the I6 engine and over the last 20k miles or so I have noticed quite a change in the overall performance of the vehicle. I did a tune up which included the spark plaugs, cleaned the throttle body, new air filter, fuel filter, new ignition coils, and a few other minor things. After doing this I did'nt really notice any change. After each time I cleaned my throttle body I noticed a slight improvement in my performance and acceleration, so last week I purchased a new Throttle Body. After I installed the new one I did'nt get much of an effect but after driving the vehicle for about a week it has really gained power. (this is because the tps is intergrated in the tb therefor the PCM must re-learn it's input.) I also have a 2008 Trailblazer LT with 30k miles and now I hardly notice any difference between the two. After several failed attempts or trying to get my sluggish engine back up to par it's finally been fixed! I would say it's definatly worth a try for anyone who seems to notice a lack of power!
 

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2004 gmc
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First report I remember of such a thing. Any chance you can take the time to put in the old one, and see if it returns to being miserable? A controlled experiment, since it doesn't justify the expense of a dyno test.
 

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2004 gmc
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Just trying to prevent a lot of folks with GOOD throttle bodies from running out and swapping them on mere hope. If yours threw a code, then that's fine, and what we'd expect. But changing it on speculation without seeing a code first, for me at least, isn't a thing I'd normally recommend knowing how the sensors work. If there's something more subtle going on, it would be good to understand it in case it starts to affect a hundred people next month. :eek:

Hmmm, in February, you posted that a new tune from PCMforless fixed the performance up so your old vehicle felt as peppy as the '08. Wish you had mentioned that in this thread for completeness sake. Did your performance deteriorate AFTER the tune in February to the point that the new throttle body is the new cure? Just trying to understand the physics and the timetable of your mods and fixes.

http://forums.trailvoy.com/showpost.php?p=688868&postcount=34
 
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