I'm new here, and need some help. I'm an old guy that has done alot of wrenching, but this one has me confused. My Son came home from college for the Holidays and his Blazer screwed up bad.

It's a 1999 "LT", 4.3 automatic. He was driving home and it quit. I towed him home and we got it in the garage. After pulling the dipstick, it was obvious the bottom was filled with antifreeze and I thought a head gasket. Drained the oil/antifreeze mix that filled the bottom and pulled the spark plugs. All the plugs were clean and dry. The radiator dumped into the crank.

He says he was driving along and it was running fine. He passed someone and it died.

When we started to pull it apart, the throttle body and air cleaner is filled with the nasty cream oil and antifreeze mixture. I'm aware that the 4.3 are known for intake gaskets failing. But, what would cause a 4.3 to be running great, and then drop all the antifreeze into the block, with clean spark plugs, while filling up the the throttle body and air flow with the oil and antifreeze jiz?

I can answer most any question about an old small block. I'm an old coot that's done most everything mechanical in the past.

What would cause a 4.3 to fill the throttle body with oil and antifreeze??? Being all the plugs are clean, I gotta think it's not a head gasket. Since the fuel injection is filled with creamy oil, is it an intake gasket? What would cause the very top of the fuel injection to have oil and antifreeze in it? It's obvious it pushed up thru the top. But why? Maybe I'm wrong, again, but there had to be something sucking the crap up into the top of the fuel injection.

Any help would be greatly appreciated!

 

I would venture a guess on a failed LIM (lower intake manifold) gasket. The junk could have made its way into the PCV valve and/or fresh air makeup for the engine and gotten into the throttle body that way.

Hopefully he didn't waste the bottom end with all that water in the oil.

 

Sants, I'm sure that the antifreeze was also pumped with the oil into the lifters. Once you remove the intake manifold, make sure you blow the Lifters and Oil Chanel. Try to do the job ASAP so as to not let rust settle in, Look for any sings of cracks on the heads/intake port area just to make sure. You may just have to replace the LIM gaskets. Good luck.

 

Sounds almost exactly like what happened to my 99 a few months ago. Catastrophic Failure of the LIM. Crankcase filled with coolant.
Oil/coolant mix blew out the throttle body, drenched the MAF and even had some on the air cleaner. Heads were fine...just cleaned everything real good, new gasket, filters and it runs good.