The Trailblazer is done. At least fior me :(

silverunicorn

Original poster
Member
Dec 4, 2011
327
Driving to the in-laws on Sunday. All of a sudden. CEL came on, blinking, and motor is struggling to stay running.

AWESOME!

Limped it home, got it to the shop, and turns out there is no compression in cylinder #5. They are suspecting an burnt exhaust valve, but have no way to tell that without ripping the motor apart. Even then, it's no guarantee that is the entire issue, if at all. He said it would be at least a 1600 - 2000 job if that were the issue.

FML. This is a replacement motor that was put in a little over a year ago. I put 32K on this one (it had 57 when I got it), which would put it almost exactly where the first motor went south also. The replacement had a 3 month, 3000 K warranty.

I am not putting that kind of money into this truck again. I thought there might be a trans issue as well, and if I were to fix the motor, it's just a matter of time until something else major goes.

So I guess I will be sparse around here. Not sure what I am getting to replace it. Looking at Jeeps and Dodge Durangos this weekend I think. I think I may stay away from GM for now, as much as I like the Acadia vehicles.

I am NOT parting out the truck, so please don't ask. I would consider selling it complete (minus my equipment that I will remove). This was just more of a rant because I was upset. And with everything else that has happened in th last 7 months, this was the LAST thing I needed :sadcry:

Chris
 
Dec 5, 2011
577
Central Pennsylvania
If it is anything valve related (or limited to the head itself) you can fix this for a little under $600. A rebuilt head can be gotten for $500 - throw a new head gasket in and all you've got is time into it. Most other things are readily available (tools, know-how). As long as the rings aren't shot and the crank/pushrods/piston are ok - this doesn't need to be a $2000 job.

I already found a head:
CHEVROLET TRAILBLAZER 4.2 LITER REBUILT CYLINDER HEAD

I'm sure that's not the only place, may not even be the cheapest.

Heck, it could be the head gasket itself. Not sure how prevalent it is in our platform but other engines have been known to blow out the firering in the headgasket and loose compression without anything obviously leaking.

BTW, how does the coolant and oil look? Coolant oily? Oil milky? Bubbles in coolant? Coolant/oil in the exhaust? How does your exhaust sound? Is there a distinct "Tick" or "Tap" while the engine is running? Is there a short, rhythmic whistle in the exhaust? Have you looked at the #5 plug - if so does it look oily, wet, or like cauliflower?

Could be galled/cracked valve seat, broken valve lock, squashed valve spring (usually scatters parts for those last two), stripped spark plug hole threads, cracked head - the possibilities in the top end are numerous - and all cured by a head replacement - worth looking into in my book, especially if you aren't parting it out and it's not really driveable. It's wrenching time.

I'm just not sure I fully buy the idea that an exhaust valve "burnt" (what do they mean by that anyway) and you suddenly lose compression. These are good strong motors that run for 200,000 or more miles when cared for well.
I suspect there's more to this than they are telling you - or that they haven't found yet.
My opinion: as long as it's not the bottom end, fix it - yourself. The hardest thing to do in a head replacement for most people is tightening the head bolts to the right spec and in the right order - and there's no magic mystery to that. It's in every Haine's manual. All you need is a torque wrench, and I think you can "borrow" those from the store - if not they're not that expensive. If you're worried about hooking all the stuff back up right when you put it back together - take pictures and label everything with masking tape and a sharpie. A head replacement can be done in a day without even trying that hard (for most vehicles).
 
Dec 5, 2011
577
Central Pennsylvania
Just for grins I looked up longblocks - RockAuto has them available at $2100 and change.
 

silverunicorn

Original poster
Member
Dec 4, 2011
327
I appreciate your information, but I am not a wrencher, and have no idea how to work on motors. I can replace an alternator, but would have no clue how to remove the top end, or even what I would be looking at when I did.

This was the second motor in teh Trailblazer already anyway. The first threw a rod at 102K.

Thanks again for your assistance. I do know soeone that is good at turning a wrench, I can see if he wants to take a look at it :smile:

Chris
 
Dec 5, 2011
577
Central Pennsylvania
silverunicorn said:
I appreciate your information, but I am not a wrencher, and have no idea how to work on motors. I can replace an alternator, but would have no clue how to remove the top end, or even what I would be looking at when I did.

This was the second motor in teh Trailblazer already anyway. The first threw a rod at 102K.

Thanks again for your assistance. I do know soeone that is good at turning a wrench, I can see if he wants to take a look at it :smile:

Chris

Wrenching is not everyone's cup-o-tee. I personally feel if you can change an alternator - you can probably swap a head out. They're just parts - sure there's setting the timing set and all that, but there's a fairly straightforward procedure for that.

If your friend's a remotely accomplished wrench, this is probably a one maybe two cases of beer kind of job.
 

MAY03LT

Member
Nov 18, 2011
3,422
Delmarva
silverunicorn said:
They are suspecting an burnt exhaust valve, but have no way to tell that without ripping the motor apart.

Did they do a leakdown test on number 5?
 

Sparky

Member
Dec 4, 2011
12,927
Sorry to hear :sadcry:

What causes a valve to burn suddenly like that?

173k and counting on mine...
 

ScarabEpic22

Member
Nov 20, 2011
728
Dang, too bad I dont need another TB or Id come buy this one from you. You've been around forever Chris, bummer to see you go.
 

Sparky

Member
Dec 4, 2011
12,927
I was actually wondering how much he wanted for it...
 

oh05ext

Member
Dec 7, 2011
166
vultures are hovering.ohhh how i love forums
 

silverunicorn

Original poster
Member
Dec 4, 2011
327
MAY03LT said:
Did they do a leakdown test on number 5?

Yes, he did. That is what led him to that conclusion. There was no compression on cylinder #5. I am not mechanical with motors, so I don't know if that is an accurate assessment, but he has been very honest to me in the 12 years we have been going to him.

Sparky said:
Sorry to hear :sadcry:

What causes a valve to burn suddenly like that?

173k and counting on mine...

That's what I was trying to find out. He said it normally can happen from bad fuel, but I don't know. I have always put 87 octane in it. Recently, the last 2 tanks have been ethanol free fuel, but he did not seem to think that would cause this. It was a used motor, which had 52K on it when it was put in, so who knows.

Sparky said:
I was actually wondering how much he wanted for it...

Have not figured that out yet. I think I will be selling it whole, not parting it out. When that time comes, there will be a post :smile:

oh05ext said:
vultures are hovering.ohhh how i love forums

Eh, I was expecting it. You just know that it will happen. It's all good :smile:

Chris
 

silverunicorn

Original poster
Member
Dec 4, 2011
327
mapanch said:
It took 10 posts for that though. Usually its the 1st or 2nd. LOL

Quoted for truth :biggrin:

Obviously I will get nothing as a trade in on anything, so I will likely sell it outright. Now here's the question.....what to ask for it?

This is what I will need to think about.

Any input?

Chris
 

BO TIE SS

Member
Nov 18, 2011
1,497
silverunicorn said:
Dodge Durangos
Avoid the Durango like the plague! They drink more gas than the Trailblazer. :twocents:
 

dfc739

Member
Jul 29, 2012
170
Des Moines, IA
TequilaWarrio said:
If it is anything valve related (or limited to the head itself) you can fix this for a little under $600. A rebuilt head can be gotten for $500 - throw a new head gasket in and all you've got is time into it. Most other things are readily available (tools, know-how). As long as the rings aren't shot and the crank/pushrods/piston are ok - this doesn't need to be a $2000 job.

I already found a head:
CHEVROLET TRAILBLAZER 4.2 LITER REBUILT CYLINDER HEAD

I'm sure that's not the only place, may not even be the cheapest.

Heck, it could be the head gasket itself. Not sure how prevalent it is in our platform but other engines have been known to blow out the firering in the headgasket and loose compression without anything obviously leaking.

BTW, how does the coolant and oil look? Coolant oily? Oil milky? Bubbles in coolant? Coolant/oil in the exhaust? How does your exhaust sound? Is there a distinct "Tick" or "Tap" while the engine is running? Is there a short, rhythmic whistle in the exhaust? Have you looked at the #5 plug - if so does it look oily, wet, or like cauliflower?

Could be galled/cracked valve seat, broken valve lock, squashed valve spring (usually scatters parts for those last two), stripped spark plug hole threads, cracked head - the possibilities in the top end are numerous - and all cured by a head replacement - worth looking into in my book, especially if you aren't parting it out and it's not really driveable. It's wrenching time.

I'm just not sure I fully buy the idea that an exhaust valve "burnt" (what do they mean by that anyway) and you suddenly lose compression. These are good strong motors that run for 200,000 or more miles when cared for well.
I suspect there's more to this than they are telling you - or that they haven't found yet.
My opinion: as long as it's not the bottom end, fix it - yourself. The hardest thing to do in a head replacement for most people is tightening the head bolts to the right spec and in the right order - and there's no magic mystery to that. It's in every Haine's manual. All you need is a torque wrench, and I think you can "borrow" those from the store - if not they're not that expensive. If you're worried about hooking all the stuff back up right when you put it back together - take pictures and label everything with masking tape and a sharpie. A head replacement can be done in a day without even trying that hard (for most vehicles).

No, you really can't fix a head issue on these trucks for $600. Not even close in reality. I had to consider this when I swapped my engine last year (also a burned valve). So let's examine the absolute best situation and assume the head you found (which was for a 2002-2005 btw and won't work due to the head redesign) will work for his 2006. I'll be quoting prices before tax/shipping in USD from O'Reilly Auto Parts. Removing the head on these engines is a pain. They use torque to yield (TTY) bolts that often break no matter how careful you are. Depending on which ones and how many break, you might have to go ahead and pull the engine anyway because there isn't enough room to get a drill in there. I got to keep my old engine after the swap because the salvage yard didn't even want a core and I broke two head bolts. But let's assume you don't break any. The new head bolts (because you can't reuse the old ones) are $60. Add to that the new head gasket which is $64. While you have everything apart you might as well replace the intake and valve cover gaskets also for cheap insurance against a future problem ($20 and $14 respectively). Then you also need an oil change to make sure you comply with any warranty the new head has (~$40). And new coolant ($30 for two gallons). If you haven't changed your thermostat or water pump recently you might also want to change them since it's only a matter of time before they go bad also ($26 and $50). While you have it apart you should also have your injectors cleaned because it's typically a lean condition that causes burned valves (not sure on price). And this is assuming the cause of the problem isn't an oxygen sensor and hasn't thrown enough unburned fuel into the catalytic converter to melt it. It's also assumed that you don't mess up the timing and have to take off the front cover when removing the cams.

Then there is the time involved. When I was trying to decide whether to swap my motor I had my mechanic uncle check the book times on it. He said to R&R the head (not including machine shop time) was actually quoted two more hours than to completely remove the engine and replace with a salvage yard motor. Don't quote me, but I think he said it was 20 hours labor for the engine swap and 22 hours to R&R the head. And it took us just a little longer than that. Up to this point it has been straightforward what you would need to replace. But what if you pulled the head and realized the rings were bad? What about the lower end? Then you wasted a lot of time and energy on something that isn't worth rebuilding.

A more realistic price for R&R of the head with a mechanic (since he isn't mechanically-inclined) is in the $2-3k range. There was a long thread by octanerider several months back that was very informative about removing the head. I was able to pick up a used low mileage motor from a salvage yard for $600. I, luckily, have an amazing uncle who has changed this motor before and had all the tools and information needed. If I didn't have him as a resource I probably would have gotten rid of it. Oh, and my old engine? I tore it down and sold most of the aluminum for scrap. I kept some of it and I plan on using the cams and crank for decoration once I get a house. :smile:
 

silverunicorn

Original poster
Member
Dec 4, 2011
327
- - - Updated - - -

dfc739 said:
No, you really can't fix a head issue on these trucks for $600. Not even close in reality. I had to consider this when I swapped my engine last year (also a burned valve). So let's examine the absolute best situation and assume the head you found (which was for a 2002-2005 btw and won't work due to the head redesign) will work for his 2006. I'll be quoting prices before tax/shipping in USD from O'Reilly Auto Parts. Removing the head on these engines is a pain. They use torque to yield (TTY) bolts that often break no matter how careful you are. Depending on which ones and how many break, you might have to go ahead and pull the engine anyway because there isn't enough room to get a drill in there. I got to keep my old engine after the swap because the salvage yard didn't even want a core and I broke two head bolts. But let's assume you don't break any. The new head bolts (because you can't reuse the old ones) are $60. Add to that the new head gasket which is $64. While you have everything apart you might as well replace the intake and valve cover gaskets also for cheap insurance against a future problem ($20 and $14 respectively). Then you also need an oil change to make sure you comply with any warranty the new head has (~$40). And new coolant ($30 for two gallons). If you haven't changed your thermostat or water pump recently you might also want to change them since it's only a matter of time before they go bad also ($26 and $50). While you have it apart you should also have your injectors cleaned because it's typically a lean condition that causes burned valves (not sure on price). And this is assuming the cause of the problem isn't an oxygen sensor and hasn't thrown enough unburned fuel into the catalytic converter to melt it. It's also assumed that you don't mess up the timing and have to take off the front cover when removing the cams.

Then there is the time involved. When I was trying to decide whether to swap my motor I had my mechanic uncle check the book times on it. He said to R&R the head (not including machine shop time) was actually quoted two more hours than to completely remove the engine and replace with a salvage yard motor. Don't quote me, but I think he said it was 20 hours labor for the engine swap and 22 hours to R&R the head. And it took us just a little longer than that. Up to this point it has been straightforward what you would need to replace. But what if you pulled the head and realized the rings were bad? What about the lower end? Then you wasted a lot of time and energy on something that isn't worth rebuilding.

A more realistic price for R&R of the head with a mechanic (since he isn't mechanically-inclined) is in the $2-3k range. There was a long thread by octanerider several months back that was very informative about removing the head. I was able to pick up a used low mileage motor from a salvage yard for $600. I, luckily, have an amazing uncle who has changed this motor before and had all the tools and information needed. If I didn't have him as a resource I probably would have gotten rid of it. Oh, and my old engine? I tore it down and sold most of the aluminum for scrap. I kept some of it and I plan on using the cams and crank for decoration once I get a house. :smile:

Thanks for the insight :smile: I went through this about a year ago and replaced the original motor. It was $2700 out the door, with a salvage motor.

I just wish this hadn't happened now (or at all for that matter) there are too many other things I need to worry about :sadcry:

Chris
 
Dec 5, 2011
577
Central Pennsylvania
dfc739 said:
No, you really can't fix a head issue on these trucks for $600. Not even close in reality. I had to consider this when I swapped my engine last year (also a burned valve). So let's examine the absolute best situation and assume the head you found (which was for a 2002-2005 btw and won't work due to the head redesign) will work for his 2006. I'll be quoting prices before tax/shipping in USD from O'Reilly Auto Parts. Removing the head on these engines is a pain. They use torque to yield (TTY) bolts that often break no matter how careful you are. Depending on which ones and how many break, you might have to go ahead and pull the engine anyway because there isn't enough room to get a drill in there. I got to keep my old engine after the swap because the salvage yard didn't even want a core and I broke two head bolts. But let's assume you don't break any. The new head bolts (because you can't reuse the old ones) are $60. Add to that the new head gasket which is $64. While you have everything apart you might as well replace the intake and valve cover gaskets also for cheap insurance against a future problem ($20 and $14 respectively). Then you also need an oil change to make sure you comply with any warranty the new head has (~$40). And new coolant ($30 for two gallons). If you haven't changed your thermostat or water pump recently you might also want to change them since it's only a matter of time before they go bad also ($26 and $50). While you have it apart you should also have your injectors cleaned because it's typically a lean condition that causes burned valves (not sure on price). And this is assuming the cause of the problem isn't an oxygen sensor and hasn't thrown enough unburned fuel into the catalytic converter to melt it. It's also assumed that you don't mess up the timing and have to take off the front cover when removing the cams.

Then there is the time involved. When I was trying to decide whether to swap my motor I had my mechanic uncle check the book times on it. He said to R&R the head (not including machine shop time) was actually quoted two more hours than to completely remove the engine and replace with a salvage yard motor. Don't quote me, but I think he said it was 20 hours labor for the engine swap and 22 hours to R&R the head. And it took us just a little longer than that. Up to this point it has been straightforward what you would need to replace. But what if you pulled the head and realized the rings were bad? What about the lower end? Then you wasted a lot of time and energy on something that isn't worth rebuilding.

A more realistic price for R&R of the head with a mechanic (since he isn't mechanically-inclined) is in the $2-3k range. There was a long thread by octanerider several months back that was very informative about removing the head. I was able to pick up a used low mileage motor from a salvage yard for $600. I, luckily, have an amazing uncle who has changed this motor before and had all the tools and information needed. If I didn't have him as a resource I probably would have gotten rid of it. Oh, and my old engine? I tore it down and sold most of the aluminum for scrap. I kept some of it and I plan on using the cams and crank for decoration once I get a house. :smile:

Didn't realize there was a head redesign, and I always hated TTY bolts. All the head / block work I did I used Grade 8 or higher (studs when practical and available) - actually used Grade 12 Allan Heads for something different on my small block.

I guess gone are the days when you could pick up a longblock at Parts America for $650, another $100 for gaskets/oil/filter/coolant/rags/paint/gojo/carb cleaner/permatex, and another $12 for beer and be driving on a brand new motor tomorrow afternoon with the hood still off ( and maybe no exhaust ). :cool: Sigh.....

I really miss being able to pull trouble codes with a fork.... :frown:

I miss being able to steal the ps belt to run the alternator when the alternator belt broke - and being able to do that on the highway by sacrificing a ballpoint pen.....
(one of the most useful object you could carry - a ball point pen - use parts to repair broken vacuum lines, broken washer fluid lines, lost carb springs, use it like a pick to remove and replace belts in a jam, make an emergency hood release cable pull, use the plug from the end to stop vacuum leaks, replace sections of rotted fuel lines)

I miss being able to tuck a quart of every vital fluid between the headlight bucket and the wheel well and still have room for a couple of rags and a couple spare spark plugs.....

Damn I'm getting old.....:no:
 

MAY03LT

Member
Nov 18, 2011
3,422
Delmarva
Hey Chris, when you said you thought it had trans problems, what was going on with it?
 

silverunicorn

Original poster
Member
Dec 4, 2011
327
MAY03LT said:
Hey Chris, when you said you thought it had trans problems, what was going on with it?

It seemed to be "hesitating" on and off, but not an engine issue, if that makes sense. Seemed to happen more in AUTO and not 2H. Maybe it was just the conditions confusing the system. Not really sure.

Chris
 

vipergg

Member
Dec 7, 2011
191
BO TIE SS said:
Avoid the Durango like the plague! They drink more gas than the Trailblazer. :twocents:
If he is talking one of the new ones with the V6 then thats not true. They are rated at 16/23 which is better than the I6 trailblazer. The new ones are nice looking though a little pricey.. I know people who own the new Jeep Grand Cherokee (same vehicle) and they love it .
 

Shdwdrgn

Member
Dec 4, 2011
568
vipergg said:
If he is talking one of the new ones with the V6 then thats not true. They are rated at 16/23 which is better than the I6 trailblazer. The new ones are nice looking though a little pricey.. I know people who own the new Jeep Grand Cherokee (same vehicle) and they love it .

When I got my TB, I ran across several sites claiming it would get 16/22. Honestly you just can't believe the ratings because they only really apply to best-case scenarios.

FWIW I've heard other people complain about durangos as well. Seems like the only complaint I've heard about the TB is that the door rubber keeps falling off.
 

vipergg

Member
Dec 7, 2011
191
Shdwdrgn said:
When I got my TB, I ran across several sites claiming it would get 16/22. Honestly you just can't believe the ratings because they only really apply to best-case scenarios.

FWIW I've heard other people complain about durangos as well. Seems like the only complaint I've heard about the TB is that the door rubber keeps falling off.

Obviously you haven't heard the many complaints of faulty ignition switches , fuel level sensors etc... :smile:
 

Sparky

Member
Dec 4, 2011
12,927
jrSS said:
And all u do for the door rubber seal is rtv and all is good.

Or let the lip rust and expand like mine, then it stays put also :crazy:
 

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