Crankshaft wont turn

[Shade Tree 77]

Hello everyone. I just replaced my intake manifold (plenum and lower) on my 98 Tahoe. The intake gasket blew and I was puffing white smoke. The gasket was visibly blown at the coolant ports, and the lower manifold showed significant pitting on the mating surface. After replacing the gasket and manifolds and buttoning everything up, I tried to restart the vehicle and could not.

Thinking I had possibly installed the distributor 180 degrees off (even tho I marked it), I tried to rotate the damper to TDC, but the crankshaft nut will not turn. I removed the spark plugs and saw a little coolant on the spark plug from the #3 cylinder. Tried to crank the key in case it was hydrolock from coolant spilling into the other ports, but nothing blew out the plug holes. Can someone help? I'm at a loss :/

 

[MO Viet Vet]

Well if you are saying you were blowing white smoke then you have likely blown the head gaskets. If it would not turn till you removed the plugs then you were partially hydro-locked. If the crank bearings were damaged bad enough when coolant mixed with oil then the crank may not turn or be very hard to turn. Dropping the distributor wrong will not keep it from turning over. So, are you saying now that the engine does spin over with the key with the plugs out?

 

[Shade Tree 77]

Correct. I did a total tear down on the top end, cleaned everything and re installed the heads (weren't warped or cracked). Replaced all gaskets, including valve stem seals, replaced water pump and it turned over. I re installed the lower and upper intake manifold, even though I thought they may need replacing in the near future. It turned over and ran fairly well, with far less white smoke.

I decided that the intake may have cracked (Had a Dorman aluminum lower manifold) so I replaced that about 5 days later, including new intake gaskets. When I went to turn it over, I got nothing. I thought that I may have installed the distributor incorrectly, and went to turn the crankshaft to find my timing mark. I am unable to turn it now, even with the plugs all out. Any thoughts would be extremely helpful.

 

[MO Viet Vet]

Correct. I did a total tear down on the top end, cleaned everything and re installed the heads (weren't warped or cracked). Replaced all gaskets, including valve stem seals, replaced water pump and it turned over. I re installed the lower and upper intake manifold, even though I thought they may need replacing in the near future. It turned over and ran fairly well, with far less white smoke.

I decided that the intake may have cracked (Had a Dorman aluminum lower manifold) so I replaced that about 5 days later, including new intake gaskets. When I went to turn it over, I got nothing. I thought that I may have installed the distributor incorrectly, and went to turn the crankshaft to find my timing mark. I am unable to turn it now, even with the plugs all out. Any thoughts would be extremely helpful.

Your initial post said you replaced the intake gasket. That is a far cry from head gaskets. A machine shop would have to check to see if heads are warped and pressure test to see if cracked. Did you do that? I gotta tell you that this other info would have been a lot more helpful when you did the original post. I really don't see why you guys hold back info sometimes? It amazes me!!!!!!!!!!! As I said, the dist installed wrong will not cause the engine not to turn unless it is cocked in there at the drive. Does the engine spin if remove dist? At this point I can guess that maybe you dropped something at the cam area on reassembly? If you initially tried to turn over and in fact it was hydro locked then you may have a bent rod?

 

[Vista Cruiser 69]

Shade,
when you say it wont crank, you mean by electric starter? Have you tried by wrench and in the other direction countercklockwise? And does he turn not a single degree or abit left and right? This "testing" might help you to consider if something fell between chain and gears or pushrods/cam area. You say soemthing abozut 5 days later replaced the intake manifold gasket. if your engine stood under water 5 days inbetween without a move - hard to believe - but there might be corrosion already somewhere between piston ring/ liner making him stuck?

 

[MO Viet Vet]

"Thinking I had possibly installed the distributor 180 degrees off (even tho I marked it), I tried to rotate the damper to TDC, but the crankshaft nut will not turn."



When he said this I assumed he put a socket on the "nut" and that is why he said he could not turn but should have thought to ask if he tried turning backwards. If nut is not tight then it may also just unthread. Either way a complete chronological order of ALL events would be helpful. By the way, good call on the rust possibility on the cylinder walls and the rings.

 

[Vista Cruiser 69]

Right, man.
misunderstood that attempt already made. Blame it on me as a non native speaker struggling with some vocabulary and the acronyms.
Still think if something was blocking the timing chain or camshaft he shoul move at least a bit. Curious to hear what came out of this story, hard to imagine that some days can build up such corrosion blocking a piston in an oiled cylinder and - hopefully- some antifreeze in the coolant.

 

[MO Viet Vet]

Stranger things have happened. Seen a bunch of it in 35 years.