Partial Crank Problem

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Jun 7, 2025 | 10:20 PM

4Kids

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The Struggle Bus¯\_(ツ)_/¯

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Partial Crank Problem

I don't drive my 6.0 Excursion that often, especially since I'm still saving up for a full head replacement job due to a head gasket leak and likely a cracked head. The other month, after it sitting for a couple weeks, when I went to start it, it cranked just a little bit then stopped cranking. Batteries checked good. Pulled starter and it tested good at AutoZone. Put starter back in. No crank. I loosened the serpentine belt and tried starting it again and still no go. Starter was a WAI brand 6.4 starter. I figured that it was just weak and tested good because it had no load on it. I replaced it with a 6.4 Mahle starter and it started right up.

After sitting for a couple weeks. I almost experienced the same thing today. It cranked for 1 second then it stopped cranking. The second crank attempt it did the same thing, but then kicked back in and started. After running it started back up several times today just fine.

The concerning part was that it wouldn't crank with the old starter (which may actually be good) even with the serpentine belt loosened, which rules out maybe a water pump or compressor starting to fail. Any thoughts on what or how to troubleshoot? Could this be a small amount of hydrolock due to the head gasket leak?

Thanks in advance!

Jun 8, 2025 | 07:39 AM

amthatiam

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From: South East PA.

I would say hydrolock due to as you say cracked head leaking head gasket, I wouldn't keep trying to start it, you can bend or break a connecting rod.

Jun 8, 2025 | 06:03 PM

4Kids

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The Struggle Bus¯\_(ツ)_/¯

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Yeah, I can't think of another reason why that would happen except for some intermittent cable issue preventing enough amps to be drawn. It has only happened after it sat for a few weeks which is why I suspected a water pump or compressor. If it is hydrolock I guess maybe I'm better off running it every day or two. I've never dealt with hydrolock, but it would seem that the only option would be to pull the glow plugs...that sounds like a major PITA. What else could be done to alleviate hydrolock?

Maybe I'll add a new water pump to the list with the new head job coming up just to be safe.

Jun 8, 2025 | 06:36 PM

bismic

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If you are curious enough, you could remove all the glow plugs and rotate the engine by hand - looking for fluid in a specific cylinder.

Jun 8, 2025 | 06:50 PM

4Kids

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The Struggle Bus¯\_(ツ)_/¯

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I'm curious but that sounds like a lot of work. I really just need to get the heads replaced. I have all the parts now and have been saving up for the labor, but I'm not quite there yet. Its about $3K for labor.

Jun 8, 2025 | 07:43 PM

bismic

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One way or another, the glow plugs will eventually be removed since you are planning head work.

Jun 8, 2025 | 07:46 PM

4Kids

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The Struggle Bus¯\_(ツ)_/¯

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Yes, very true! In fact, I have a full set of new glow plugs and harnesses in hand. However, I don't want to remove them before the head work is ready to be done. I'll make sure that I mention this whole scenario to the shop so they can be on the lookout for it.