12.7 tough spin when cold

It's old and tired alright, but so am I. It's not going to get its long-overdue rebuild any time soon. If there are a few things I've always hoped for in twenty years with this old truck, it's that it doesn't throw a rod or refuse to start somewhere far from home. It's been very good to me so far—better than I've been to it.

It runs good. It starts quickly, every time (almost). What happened this morning is a fluke. It happened two years ago and didn't happen again until this morning. I'm leaning toward what Rideandrepair posted, that I've got a leaky injector. The fact that it happens only rarely may mean that the injector only leaks down into the cylinder at a certain point in the engine cycle. If the engine happens to stop at exactly that point, then the injector leaks fuel, otherwise, it doesn't. That's only my theory. If it were a coolant leak, it would happen every night, wouldn't it?

One thing I don't get is this: It flat refused to turn beyond a certain point when using the starter. It's like it was hitting a wall. I watched the numbers printed on the back of the belts. The engine moved only about 15 or 20 degrees of turn before it stopped cold, and then when the starter was released, it rebounded to its original place. It was stuck in the exact same place, every time. Yet, when I barred the engine, it barred easily, right past the place it was getting stuck with the starter. After I barred it through, it started, and now it's fine—no clue that there had been anything wrong. How could I bar so easily through something that the starter couldn't get past no matter how many times I hit the button?

 

Yeah, Rideandrepair, I was thinking that too. It doesn't jam up, though. When I take my thumb off the button the engine jumps right back to where it was. The engine is always very loose. A bad bearing or a bad spot on the flywheel would jam it right there, seems like. It acts like it's coming up against compression, against a point beyond which it will not turn, exactly like if there were liquid in the cylinder, and then, when the starter is released, compression pushes the crank back to where it was. Keep hitting and releasing the button and it keeps rotating back and forth, remaining exactly within the same few degrees of rotation. The starter absolutely will not move it past a few degrees of rotation. However, I can easily bar it past the trouble spot, and once I do, she spins and starts. Also, once it's running, and I shut it down, and then jump the solenoid with the key off, she spins and spins, all the way around, with no hangup. No, I don't think it's a bad flywheel, although I did consider that possibility.

 

yes

 

ha ha
yes I'm sure

 

Started right up this morning, instantaneously. I'm cash-strapped. It's hard not to put 'er back on the road right now—put some dough in the bank.

I ain't been on the road for the entire winter—missed all those good rates. I could whine "woe is me", but on the other hand, I enjoyed the winter at home, with plenty of firewood, hot coffee, and a hearty breakfast every day.

Now I'm about to take a gamble on an engine that has run almost 2 million miles without a breakdown. Not long after I bought the truck, back in about 2000, a mechanic at a local dealership told me that the oil weeping down the left side of my block was not from the cam seal; it was from the head gasket. That was well over a million miles ago, on many coast-to-coast runs. I can't praise highly enough the Series 60 Detroit.

What really interests me at this point is the peculiar nature of the mechanical situation. I wondered if anybody else here had experienced the same thing.

At least now I know how to get past the predicament if I'm caught with it out on the road. I found that I can bar it through the dead spot and that once I do... she'll start right up.

I'm not forgetting that the problem might be a slightly leaking injector. If that's the case, then perhaps there is no need to worry about imminent catastrophic engine failure.

I'm putting all my worries behind me and going back on the road. If anybody has any information about the strange, intermittent, infrequent problem of the engine apparently hydrolocking, (slightly) (temporarily) I'm all ears.

Thanks for all the replies.