Yeah, it's as bad as the subject implies. Here's a little history...

The vehicle was mistreated by the previous owners. I bought a 2000 Chevy Blazer (4.3L 4x4 LS) a couple years back, got a great deal. Problem is, they never did the routine maintenance. I obviously didn't know this, and have been fixing minor problems since.
Recently, she overheated a second time; a year ago the coolant had coalesced into the rusty sandy gunk and I had the system flushed by the dealership. They did a crappy job, but at least the gunk at the cap was gone. I hoped things would be okay until she overheated again just this past week. This time I decided to flush the coolant system myself, knowing I'd probably do a better job and doubly make sure things were done right. As I was taking the overflow tank out of the car to give it a proper cleaning, I noticed there was oil on the top of the water. (started the process with a garden hose) I questioned the oil and it told me to check the engine oil dipstick, where it and some 10w-40 decided to hang out. The couple produced some nasty chocolate milk looking crap, and from that point on I knew I was screwed.
Decided to check things out; took the valve covers off and found horrible coffee coolatta looking gunk all over the place. I knew it was either a head gasket or intake seal; so I started first (after scouring these forums) with the intake manifold. It was pretty gross in there too; but the SUV has almost 100k miles on it. The intake seals were not too bad, so off came the heads. (Pain in the rear; the headers are a PAIN to take off on the left side) I found a busted head gasket and now I'm ready to put her all back together. There was coolant all over the place mixed with oil; and before I put it all back together, I wanted to ask a few questions to this great blazer think tank.

I know coolant on the cranks, bearings, etc in the engine block is no good. My plan is to get her all back together, after cleaning and machining the heads, and first filling up with some new oil, then draining it after running idle till at temperature, then doing another oil change. I'll probably drive it for about 5-10 miles, and perform another oil change. Possibly after that, go a week of normal driving, and oil change a final time, and then putting in synthetic as a final hope that all will run well after this. I have to flush out the entire cooling system; radiator, heater core, and transmission (automatic). Also going to swap out all the cooling hoses just because they're caked on the inside with rusty looking gunk; and the majority of them had to get cut off because they've probably been clamped on for 9 years.

Does anyone have advice or any extra precautions, experiences, or just a general good rule of thumb for what I'm about to do? I have pictures to post, and they can be used at will by forum membership for anything that might be needed of them. They'll be up hopefully when all is done. Please keep explanations and jargon fairly simple; I'm a fighter aircraft mechanic by trade and this is my first time delving into the realm of an internal combustion engine.

Thanks in advance for any replies; and wish me luck.

Edit: I was reading the guys problem below me with the leaky rad line. The aluminum lines that go to the oil and the tranny, I am leery on trying to figure them out on how to disconnect them. Chilton's says undo the clip and pull it out; but after fumbling with some needle nose pliers, I'm scared to pry and break an expensive part. (as if this isn't expensive enough). Any advice? They have a threaded 'rosan' type fitting, but also has a paperclip sized clip thats around it. I'd really like to not break these. Thanks.

 

I think you are being overly cautious with this. Too much water/coolant in the oil can wash the bearings causing damage (water is a poor lubricant), but we are talking predominantly water here. Once you get the water out of the system by draining the coolant, you may want to run an engine flush to make sure all of that nice milkshake stuff is out of there, but after that, do oil changes as you regularly would.

As far as the clips on the oil lines go, hopefully the illustrations below help:



Or just check out THIS POST which details the replacement of the oil cooler lines on the 2nd gen.

 

The illustrations do help; thank you.

What are the procedures for a proper engine flush? Will I need any specialized fittings or some sort of pressurized oil cart to provide the necessary results? I suppose I am being overly cautious, I'm running off of aircraft maintenance procedures... and any contaminates in oil or hydro systems results in an extensive flush of all lines and reservoirs. I was looking at my rocker arm bearings and they are filled with the coolant/oil mixture. There was a lot of water removed but I'm going to put some compressed air to them and hopefully get out as much of that mixture as I can before reassembly. Or then again... maybe that too is being overly cautious. I'll follow your advice, your the car mechanic here.

 

I am just another DIY-er like most people here. By engine flush, I mean the flush in the can stuff. Just follow the directions on the can.

 

Sounds easy enough. Thanks for the help. I will get those pictures up soon; everyone can gawk at how disgusting it really was!

 

ravenhurst,
I have been in your shoes, although it was a '93 and I created the problem myself. Long story short. I swapped an '85 4.3L V6 into the '93 and had to drill one accessory bolt hole in the passengers head. Went a little too deep and had coolant mixing with my oil.

I popped off the intake manifold and valve covers to flush my engine.
I took out my oil pan drain plug and put a empty catch can under it. Then poured as much cheap oil as needed to wash all the sludge away, then a did it again. Replaced the oil filter, put the engine back together, filled her with oil and let it idle for 5 minutes while I checked for leaks, still using cheap oil. Drained that, changed the filter, topped off and let it idle for 20 mintues. Repeated the process and this time took it out for a 15 minute drive to get her up to operating temp. drained/ filter one more time and filled up with good oil.
2 years later and my son still drives it.

As for the cooling system. The gunk comes from air in the system. Replace the rad cap, hoses, flush throughly with a chemical, and top off. Drive and check that it is topped off.

Like swart said, the tranny cooler lines are easy to get off, even at the tranny end with the quick clips. I had to pull my tranny to rebuild it and didn't know aobut the quick clips until after I got it out. Trust me, the quick clips are much easier than removing the exhaust system to get a wrench in there.

Post up if you still have questions.

My engein swap thread with pics of hte oil milkshake.
http://chevytruckworld.tenmagazines....sp?album=18998

milkshake.
http://chevytruckworld.tenmagazines....nr2/245122.jpg
http://chevytruckworld.tenmagazines....nr2/245114.jpg
http://chevytruckworld.tenmagazines....nr2/245113.jpg

 

Few things are as controversial as the chocolate milkshake, and few beverages have such outspoken partisans. Approximately half of all devotees believe the shake should be made with vanilla ice cream and some kind of chocolate sauce, which makes for a creamy drink with chocolatey overtones.Kilwin's super-rich chocolate ice cream plus whatever syrup they're using equals a milkshake so powerful it's almost invasive: the salivary glands start freaking out when the stuff is only halfway up the straw, there's a feeling of heat at the back of your head, and every nerve in your body begins twitching as though in expectation.

johnyymathew
Promoter

 

I added all my photos to photobucket. I'll paste the link to the album below. Everything that came back from the machine shop looks awesome. They resurfaced, oven baked, and checked my valves, as well as resealed them with the parts from my felpro kit. Hopefully I'll have her running by tonight, so keep your fingers crossed!

On a different note, I'm looking to replace my coolant overflow tank. I can't find one anywhere. Mine is pretty gunked up with a hard coating of that old dexcool. It's been like this since I bought it, and I put some engine flush in it and let it sit, but it didn't help much; even with throwing in some lug nuts and shaking it around violently. If anyone knows a good vendor, please, let me know!

http://s12.photobucket.com/albums/a2...20Maintenance/

 

Seems like you have it well under control.
Let us know how it turns out.

 

Here's an update on the status.

1. Put the valve covers on the wrong sides; and only found out after everything else was completely bolted on; discovered this when I went to put my air filter assembly on and the oil filler was in the way. I backtracked my steps to figure out how in the world this happened, and all of the engines in the chiltons/haynes have the filler on the left side. I went through some old pictures of my engine and found that it needs to be on the right side. Blah. Just added about an hours worth of work for nothing.

2. I still filled it with oil; and filled it to capacity. Although I measured the oil from the jug, the dipstick shows no signs of oil. My question to the forum is will it take more oil than usual to fill up or could this be a potential problem with the dipstick tube? It had been wiggled out of the way during the head and exhaust manifold process. Looking with an inspection mirror, it looks as thought it should be fine.

3. Readers will have to consult the photos here...


Upon rebuilding, I found a small vacuum line that I have no idea what it does. It starts here, in the photo above, and routes to this part below...


The rubber hose that curves off to the left in the photo is the vacuum line in question. I have no idea where it goes, and my gut tells me its an overboard drain because the end of the house has nothing but dust on it. Can anyone tell me the purpose of this hose? The parts visible run along the firewall right under the wiper blades.

Thanks in advance guys.