1999 Blazer 4.3L Engine Overhaul
 

Hey guys, this is my first real thread on this forum other than a quick question here or there. This thread is documenting a complete and total overhaul on the 4.3l motor of a 1999 Blazer LS. This truck is my dad's ( I have a black 1998 2 door myself) and due to a combination of neglect, several over-heating occurrences, mixture of Dexcool with regular coolant and water causing a nice thick gummy substance to fill the cooling system, and finally a blown intake gasket around the coolant passage in the head allowing fluid to sneak into the combustion chamber and stall it out.....the motor came due for a rebuild. At the very beginning while we were weighing out our options of whether or not to go with a crate motor or to go ahead with the rebuild, we figured that for maybe $200-300 more I could do the rebuild and have more control over the quality of the work and be assured it's not some slapped together 'Hecho en Mexico' deals. Well now I am toward the end of the build and I figured why not chronicle this process and perhaps help someone else make their decision and learn from my mistakes (....you'll see). So without more yapping on I will give you guys some pics of the carnage to feast on, enjoy...

Here it is the day after it was towed to my house...I got to work quickly tearing it down.

http://i27.photobucket.com/albums/c1...s/DSCN9841.jpg

Removed the upper intake, wasn't too surprised by the amount of carbon build up

http://i27.photobucket.com/albums/c1...s/DSCN9842.jpg

http://i27.photobucket.com/albums/c1...s/DSCN9845.jpg

Then I moved onto the lower intake manifold

http://i27.photobucket.com/albums/c1...s/DSCN9848.jpg

http://i27.photobucket.com/albums/c1...s/DSCN9849.jpg

And thats when I found the issue...

http://i27.photobucket.com/albums/c1...s/DSCN9855.jpg

http://i27.photobucket.com/albums/c1...s/DSCN9853.jpg

The heads and block were gummed up pretty bad with this stuff

http://i27.photobucket.com/albums/c1...s/DSCN9852.jpg

http://i27.photobucket.com/albums/c1...s/DSCN9856.jpg

The gasket was broken up around the coolant passage adjacent to cylinder #6 so I'm guessing this is what cause the stalling issue. I was worried about a possible hydro-locking issue as you can't compress a liquid in a cylinder, but I think there was enough blow-by or there just wasn't enough fluid because the rod did not bend thankfully

Here's a nice chunk of the stuff

http://i27.photobucket.com/albums/c1...s/DSCN9851.jpg

Well I think 10 is the picture limit per post so I'll end here and pick it up in another post.

Those rear coolant passages look yummy! LOL

I am working on getting the picture posting limits changed. It is a bother... You could display the automatic thumbnails from Photobucket and link to the full resolution shots if you'd like. Check out the Help & Suggestions section for the Image Posting FAQ.

wow that looks nasty. Sorry to say but I don't think you'll be able to do a complete overhaul for $200-$300. You'll probably be near that in gaskets alone

Nice guuk! How much of the internal work are you doing yourself. An extra $200-$300 is worth it IMO just for the experience, if you have the time. Keep the updates coming.

im pretty sure he meant 200-300 more than buying a cheap crate motor that was made in mexico, just going by what i read into his post.

yes, that is exactly what i ment. perhaps i worded that alittle awkwardly. its rather comical now because the build total is now more than double what a crate motor would have cost. anyone reading this thread and contemplating doing their own rebuild.....run, do not walk, to your nearest engine supplier and just get a crate. the warrenty and lack of headaches is worth it alone. no dealing with shady machine shops, parts delays, interchangability issues, etc. if this were a normal run of the mill small block i could have built it with parts i already had. im going to post up the rest of this thread probably later on today when im back on highspeed (the pics take forever on dialup). this project has been nothing but headaches from the get go and i highly regret not just popping a new set of gaskets on and giving it a flush and calling it a day. oh well, you live and you learn i suppose.

Goes to show why you shouldn't mix dex cool with regular antifreeze. Looking forward to seeing the rest of this. I am thinking about picking up a spare motor to rebuild, and it is always good to see what I might face before I actually get there.

Dexcool and "regular" coolant mix is not a problem, that gunk looks like "sealing" compound that was added over time....I have been running a mix for years....

Yea, I agree about just buying a crate motor from a reputable builder. But I gotta admit, I am very entertained by the pics! more please!

I trust my machine shop and any engine given them for overhaul gets it's warranty. I would never go for a cheap crate engine "Made in Mexico".

Over here a crate motor is expensive anyways no matter where it comes from around 4'500 $ while a rebuild costs about the same.
So I'll not bother risking to get a "Made in Mexico" when I can do it at the same price decently with material as good as OEM or better.

I'll probably do that in 1 - 2 years using the engine on my scrap Blazer and have it rebuilt.

As I can disassemble and re-assemble everything myself i'll get cost down to 2'000 or 3'000 $ - and do some nice things to the engine such as a proper porting job, balancing everything starting with pistons, rods, and crankshaft, then balance all together with the flywheel and maybe add 0.05 to 0.08 bar to the compression.

When it comes to engines nevertheless my heart beats for an older Alfa Romeo 4 cylinder DOHC or V6 - these are real nice engines and make the one in my Blazer look like a tractor.

Nice work though on your Blazer. Thanks for the pics very interesting and good quality to get an idea what it looks like below the spider.