Strange rattle at front of the engine

It got worse. Went out to start the engine a week or so ago and the engine would not turn over. Not the usual things, the engine wouldn't turn. Since then I've backed the crank off a little over 1 turn with a ratchet wrench then turned it forward again and it stopped in the same place. Feels like a hard stop but I didn't try to force it. It never made any other sounds before it stopped running other than the rattle it had been making when I turned it off the last time it ran. Probably turned it about 400-450 degrees each way. Stuck a camera down the distributor hole and the timing chain looks normal. Pulled the valve covers and none of the valves are down enough to touch the pistons. None of the rockers are loose.

Jim

 

Pull the plugs. Perhaps hydro-locked?

Any way you look at it, that's bad news.

I had a Chevy 350 lock up at a gas station. The alternator had been noisy for the previous twenty minutes. But in that case, the engine wouldn't turn backwards or forwards. Once I took the belt off, the engine would crank.

About three weeks ago, my Trailblazer engine locked up. Again, wouldn't crank or turn backwards until it shredded the belt. A/C compressor bearing seized.

 

Jim when you turned the engine over by hand did you hear any noises? Like something sliding on your oil pan?
I drove from Florida to Maine years ago.
When I got home I parked my truck nothing unusual, the next morning I tried to start the truck. About half a revolution and a hard clunk stop. I could turn the crank back and forth about a 1/2 turn. You could hear what I thought was a rod slide across the pan. I dropped the pan to check things out. Piston stayed up in one hole with the pin and about an inch of rod. Crazy that it broke while cooling down.
Good luck

 

Maybe not so crazy. My Dad tells a story of his first car, I think it was a 55 Olds. Drove it down to the shore (a couple of hour drive) and parked it by the beach. Next morning , seized.

 

That would be strange, yes. If the engine has to come out that won't happen until this winter when I can get some of the guys up here to help with it. In fact it won't even go back on the lift for a few weeks as there are jobs ahead of it. And I think it'd be very hard to pull the pan with the engine in the car, but I can see it could come to that. Damned inconvenient actually. Engine has about 30,000 miles on it since the rebuild and was doing just fine. No oil consumption, smooth and powerful. We had just gotten done with tightening up the end play on the oil pump and fixing the leaks in the AC system, and for the first time were getting 44 degree air when the noise showed up. One guy thought it could be a rock in the bellhousing against the torque converter, I've heard of stranger things I guess.

Jim

 

Did some more diagnostic today and the verdict is: Hydrolock. Looks like new head gaskets are in order.

Jim

 

Which cylinder(s)?

Does the crank turn when the spark plugs are removed?

 

I've seen a Hydro locked engine bend rods from trying to start it . People don't realize how strong a starter motor really is .

 

I've also seen rod bearings mashed out. I would pull the engine and inspect the short block. It's only a little more work at that point and less chance of paint damage vs. Pulling the heads in the car.

 

Probably good advice but it isn't entirely my decision since this was a group project. I'll mention it though. Now as to the affected cylinders, I saw antifreeze on plugs # 1,2, and 5. With all plugs pulled when I cranked it #1 spewed. Don't really know about the other two. I think it's an odd thing that 3 cylinders would have leakage and on both sides of the engine. Steve told me we had to re-torque the head studs due to leakage but I don't remember that. It has TA SE heads and ARP studs. As far as I know the engine has never been overheated enough to cause any warpage and generally runs 180 degrees. The block was decked during the rebuild. Head gaskets were almost certainly FelPro. My best guess at this point is that we did not have the special ARP stud lubricant and MAYBE we didn't have the TA recommended torque figures. Probably used ARP numbers I would guess. Possibly stock numbers were used. And maybe that just wasn't enough and at the first occasion of leakage the gaskets were damaged. But that's all just a guess really.

Jim