Hello everyone. I have a 05 2dr 4x4 automatic Blazer 250xxxkm. Some unfortunate events have brought me here. Today my shop informed me that I have no compression on cylinder six. I have a cracked oil pan that is jb welded and still leaks. My rear main seal leaks. I have thought about getting a used engine however I think I would rather try and rebuild this one that I have. I'm thinking I will try to find a marine intake to put on while I do this so I can hopefully have a reliable engine for many years to come. I'm planning to pull the engine out and put it on an engine stand in my garage to work on it until it's ready to go again. I'm looking for anyone with experience doing this, any tips for pulling the engine and doing the rebuild? What parts should I all replace while I have it apart? I see on Chilton they say to pull the transfer case, and transmission before pulling the engine out. However, I saw it done with the transmission still in and also see people talking about it this way. Could anybody shed some light on this method of pulling it out? Thanks in advance.

 

I'll be following!

But one question: Would buying a long-block be an option to save you some time? As for the cost, I have no clue.

 

If the head of the valve or a piece of the valve came off, there may be a lot of damage to that cylinder. Furthermore, no reason to rebuild a Blazer v6 unless you simply want the experience. You can buy a Goodwrench rebuilt from Jegs (no core charge with Jegs) for less than the cost of parts and machine work (around $2300). Plus you get a warranty. I have 60k miles on mine so far.

If you want to know what to replace in an engine, the disassembled engine will need to be evaluated by a machine shop. With 250K miles, I would suspect it will need everything replaced and all machine work done if it can be saved.

The problem with trans in place is getting to the ground straps and a fuel line clamp fastened to the back of the heads, as well as the top drivers side bellhousing bolt being blocked from coming out. When the transfer case is off and rear of engine is hanging, all of this is easily accessible. If you figure out how to deal with the bellhousing bolt, the trans in place method can be done with a lot of finesse and cursing. I cut a small flap in the floorboard underneath my gas pedal for access with a dremel cutting wheel and then bent it back. If this is your first engine R&R I wouldn't recommend trans in place. This one is about as difficult as it gets, especially that way. Its very tight between trans and front diff so flex plate barely comes out in front of trans bellhousing. Trans has to be raised on a floor jack up against the trans tunnel to get the flexplate in and out in front of the trans.

 

Do remove the passenger exhaust manifold. Its easy way to get the starter in/out and motor mount unfastened. Also you avoid damaging your evaporator housing with the engine when it is coming out. Since you have a 2005 there is no EGR tube in the drivers exhaust manifold so take it off too for access - you will be glad that you did.

I call it peeling the engine out of a Blazer!

If you decide to actually do this, we can advise further.

 

LOL

I once replaced a 318 in my 71 Dart. Just looking at my Blazer, I get chills down my spine when I consider how much harder that would be.

 

Christine, I thought about swapping in a different engine maybe. However, being that getting it back on the road is a priority I don't think I'm up for doing all that custom work to make a different engine work in my truck right now. Les, you make a good point about how cheap they used engines are. It just sucks because I live in Canada and I see all these for sale in the states! I called up the dealership here this morning and it turns out they can bring me in an engine from the states for $3650 Canadian plus tax. This isn't too bad being that it is the LU3 engine, and on jegs they are $2800 American I believe. I also want to bring this up, you may already know. A fuel line nut was just dropped down into an intake port, that port just so happened to be #6. So I have a picture here from before I took the nut out of the #6 intake valve. It doesn't look bent or anything to me, this is where I'm getting confused as to what's even happening here. It also must be something to do with this intake valve because I'm getting gas pushed back up into the plenum. I suppose I need to take off the valve cover and the head and see what's going on, I think either way I will take this engine apart before I make any calls to get a new engine or not. Thanks for the tips for removing the engine, this will indeed be my first time pulling an engine out. I am inclined to try and do it with the tranny still in as pulling out the whole drivetrain seems like A LOT of work, I have also heard that having the auto means that I won't need to move it as far forwards until I can start lifting the engine.

 

I would just pull the one passenger side head and see if it could be easily fixed with a new valve and minimal work (if zero damage to piston or cylinder - no marks or imprints from the loose piece). It's not like it is going to run like it is anyways. You can always pull the engine later if it really needs to come out. Only difference is removing the intake and head bolts before pulling the engine instead of afterwards. On a high mile vehicle, sometimes its just better to fix just the specific problem instead of getting into a complete rebuild. I once had a 49 Ford pickup flathead 6 that dropped a valve head and munched a big hole in the piston. I should've just fixed the one cylinder with a new piston and stuck a valve in it - but I chose a complete rebuild. It was very costly. Another time, we bought a beautiful 78 Pontiac Bonneville 2 dr for $100 for my 15 year old son (was in 1994 IIRC - yeah I'm an old fart). Pulled one head and fixed 1 valve on it - put a $50 junkyard transmission in it - he did 100% of the work and I closely supervised. He then had a good car to drive for very cheap and a good experience to tell to his friends.

Can't make heads or tails out of the photo. Sorry.

Start soaking down the exhaust manifold to exhaust pipe bolts with penetrating oil (at least several days)! Rat-a-tat-tat of an impact adjusted to lower pressure will get them loose a lot better than a big ratchet and hard twisting (breaks off the bolts). Broken bolts may be unavoidable, though in a 250K mile vehicle. In any case that right hand exhaust manifold HAS to come off for access to the lower head bolts. Note that head bolts on this engine are TTY (Torque to yield) so they will need to be replaced.

Marine intake won't do you any good unless you are trying to put big injectors in it to handle a high horsepower application. If power is your goal, a late 90's Truck Vortec 350 would be a much better choice and will work with your stock computer (which also runs your trans and 4wd and many other systems in your vehicle). Aftermarket still has some performance parts for the V8 engine (but pretty much zero for the V6). Personally I think the 1996-2005 Blazer V6 has pretty good power as it is. Much better than earlier years, so really not so much to gain with the stock V8 (25% - 50HP).

 

Les is an excellent guide for your project so I will leave the details to him but I strongly agree with his suggestion to get that head off first and see if you can repair the failed cylinder. You should review the compression test results for all 6 cylinders first however.

I had a Toyota with 167,000 miles on it where the head bolt threads cut loose in the center of the block. I drove it running like crap for another 5k miles filling up leaking coolant, compression lost in one cylinder, overheating, ... I then pulled the head, had it rebuilt, drilled and tapped the block threads, used inserts and reassembled, all in the truck. While I was in there, new timing chain, water pump, variable valve cam etc. I am now at 285,000 miles and going strong. Its not a dropped valve example but it shows you what is possible. BTW that dropped cylinder was as shiny as a monkeys hiney from all that steam cleaning. I had a hard time getting the other 3 cylinders as clean for reassembly.

George

 

Ok so I went down to the dealership to talk more about getting a new engine from them today and they told me all of what comes with the engine if I were to get it. Also said it comes with 3 yr or 60k km warranty. Looks like a great deal, it looks like I would need to swap the flexplate, water pump, spark plugs, and of course put an intake on. I never made up my mind to get it towed back home yesterday so I won't be able to do anything until I get it back on Monday. The first thing though will definitely be pulling the valve cover and head off and I can go from there. If it does come down to rebuilding or buying this one from the dealership though I think you have convinced me to just go with the new engine, Les... It makes more sense just because as you said by the time you factor in the machine shop cost with all the new parts it's close to what this engine is anyways. Not to mention the time it would take to rebuild it and it's also a lot of parts to put in correctly too if I just buy this engine it's already all put together for me and ready to go. I am most worried about getting the exhaust bolts off, my exhaust blew apart when it was misfiring a while ago at the joining point before the muffler. It was very ugly getting these bolts off. I ended up breaking them both off with the impact then needed to cut relief cuts in from the side of the flange to free up the pressure so I could hammer out the pressed in stud, then just put a bolt in its place. I had to repeat this exact same thing with the relief cuts when I did a custom exhaust for my BMW too. You could say I don't have very good luck with exhaust bolts LOL. I am now on the fence about getting the marine intake manifold as well. Mainly because of how much it will cost already just to get it back on the road without the marine intake. If not now I would still like to do this in the future, I like the normal style injectors and steel fuel rail, it seems like it will last a lot longer. Thanks for the input George, I was thinking this too. I asked the guy at the shop about it briefly and he said that the tech didn't do all 6 cylinders he just did cylinder 6 and the one right beside, cylinder 4. He told me cylinder 6 had no compression and cylinder 4 had good compression. I will clarify this again with him on Monday and try and get the numbers. I have found some new interesting points. So I have a picture here of when I pulled the intake manifold off prior to cleaning it, just all the gas had evaporated and dried up. Lots of debris can be seen at the very back and at the side of the number six intake port. Now, when I put in the second new spider assembly, and couldn't find it leaking anywhere until I turned it over then would find gas all under the plenum. The gas was pooling in these same spots, the very back under the regulator and beside the number six intake port. After the gas dried up I was left with another small pile of this mystery debris in the back of my intake where the pool was (pictures below). This didn't catch my attention before but I know the gas going into the spider is crystal clear, very clean. I have depressurized the system many times now and have seen this, it's not black like what's pictured. To add on, when I had the intake manifold off I cleaned the intake the best I could before putting it back on. So this makes me think my mystery debris must be coming from gas washing up the intake port and taking debris with it then it would pool up and evaporate leaving me the pile of debris? I can't think of any other explanation of how I would get that dirty gas in my intake manifold so quickly. I couldn't have run my engine for more than 5 minutes to end up with what's in the last picture. Now I changed out the spider last year about exactly a year ago and I don't remember any of this mystery debris. This sure explains a lot, like why my fuel pressure was jumping erratically when I had the gauge hooked up. I'm starting to think whatever is going on now might have been my problem from the start of this saga, this gets me excited for Monday to start tearing into this thing...

 

That picture of the valve looks like there is ice on it and in the runner to me.