I was replacing all my gaskets on the 98 S10 4.3l automatic with a Felpro head gasket kit NAPA sold me.

After all was done and put back together, got into the cab and prayed for a startup.

Didn't happen.

Instead it tried to turn over for about half a second and came to a clank dead stop.

Heart fell out of my rectum.

So went through what I call a process of elimination. Check the battery, all serp wheels, starter, distributor timing, all was good. Nothing was seized..

Except for the crankshaft, I got under the truck and put a socket to it and it would not budge clockwise at all but will turn counter clockwise no matter how many times you turn it.

I never disconnected the transmission or took off the oil pan, or even removed the timing chain cover and made sure nothing got in the lifter arms where the air intake sits.

I did have to reset my distributor timing to TDC and only turned the crankshaft clockwise with the heads on after replacing the head gaskets and it turned fine with no issues at all with the lifter arms installed and intake manifold.

I repeat, all serp belt pulleys spin just fine, nothing is seizing and would cause the camshaft to not turn over because of the serpentine belt.

Does anyone one know what might be going on, maybe can point me on the right direction to finding out, or ideas before i got to take it all apart and restart?

It has 130k miles on it and was running just fine with the occasional thrown code for a misfire witch what made me want to do gaskets.

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    Welcome to Motor Vehicle Maintenance & Repair! Mar 9, 2019 at 9:48

1 Answer 1


Take the valve covers back off, loosen all of the rocker arms, and take out the spark plugs. Then try and turn the motor back over using the socket wrench. I suspect what you've done is not tightened the rocker arms correctly and have one (or more) of them too tight, which is causing interference between a valve and a piston. If so, hopefully you haven't bent a valve in the process.

To properly set the valves on a hydraulic tappet motor (assuming you don't have solid lifters on your engine), do the following:

  1. Find Top Dead Center (TDC) on the compression stroke for cylinder number 1 (both push rods should be even, if not, rotate crank another 360°)
  2. With your fingers on the push rod, rotating it, tighten the rocker arm until the pushrod just stops turning, then tighten it 1/2 turn more
  3. Do the same for the other rocker on the same cylinder
  4. Turn the crank over ~120° and do the steps #2 & #3 for cylinder #6
  5. Turn the crank over ~120° and do the steps #2 & #3 for cylinder #5
  6. Turn the crank over ~120° and do the steps #2 & #3 for cylinder #4
  7. Turn the crank over ~120° and do the steps #2 & #3 for cylinder #3
  8. Turn the crank over ~120° and do the steps #2 & #3 for cylinder #2
  9. Turn the crank over 360° to ensure the motor turns freely throughout the range

The idea is to have the lifters on the base circle of the cam when you adjust them. You can put your finger over the spark plug hole and know when the piston is coming up in the cylinder as air will push out past your finger. Do not use the starter to turn the engine over, but rather, use the crankshaft pulley bolt with a socket/ratchet.

I'm pretty sure you didn't do this correctly, because if you had, you'd have noticed the stoppage before you ever tried to start it.

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