# Ford 4000 3 cyl diesel - head gasket or crack?



## .netDude (Nov 26, 2004)

2 days ago, went to turn over the engine, it turned a couple times then gave a sharp crack, like someone hit the top of the engine with a hammer, then stopped turning. I let it sit for a couple minutes, warmed up the manifold heater, and it started and drove it a couple times since, just to put out a couple round bales. Today, I checked the radiator and it was down to the core. I filled it, let it idle for a few minutes, after 4 or 5 minutes the fluid turned 'frothy'. There is white smoke when it's cold, goes away when it's hot. The oil seems ok, doesn't seem to be contaminated, but I didn't pull the plug, only checked the dipstick. 
Is there anyway I can determine if it's a head gasket or a crack in the (cylinder?, head? something else?) without ripping it apart. I've changed a head gasket on an 8N, but this looks like a much different beast. 
Thanks.


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## Guest (Apr 11, 2008)

If you could hear it, it almost certainly was a crack, but even if you only need to replace the gasket, you'll still have to pull the head, I cracked the block in a chevy 290 straight 6 and it was a very like a gunshot, and never cranked again. Anyway, here's a discussion about the identical problem. http://www.acmoc.org/ACMOC_BB/showthread.php?t=1502


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## .netDude (Nov 26, 2004)

As for the sound, I was also told that it could probably be from water that leaked on top of the cylinder. The pressure from the cylinder could have made that sound, not so much a physical cracking of metal?


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## agmantoo (May 23, 2003)

Ascertain if the oil level in the engine has risen. 
To check for a blown head gasket or cracked head remove the fan belt and with the radiator filled start the engine and observe for bubbles in the radiator with the filler cap removed.
Report what you observe.
I have never heard nor have I had anyone to report hearing a crack occur in an engine. These cracks that do occur are usually very small and probably undetectable to the human ear over the noise of the engine.
If you have to use the machine leave the radiator cap loose to permit compression to escape and to prevent pressure from forcing coolant into the engine.


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## .netDude (Nov 26, 2004)

Thanks agman, I'll try it with the fan belt off this weekend. I did that with it on, and I didn't get bubbling in the radiator initially. I could see down to the core. After 4-5 minutes, is when it got foamy / frothy. As for the sound, it was definite. Sounded like someone hit the top of the engine with a big hammer, then nothing - completely stopped turning. Not saying that what I heard was a crack in the head happening, just that it was a loud bang.

In either case - gasket or head - any idea of the labor cost to have it fixed? I think I'd have to have pro do it, doesn't look as straight forward as the old 8n.


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## FordJunkie (Nov 23, 2007)

Usually you won't here anything but with the engine just being cranked not running what you could have heard was a valve being helped closed by liquid in a cylinder (hydraulic-liquid compression in the cylinder) which would slap the valve closed. Head or gasket leaking coolant into the cylinder very rare to here it but you may.

I would "guess" about 20 hrs. shop time if it doesn't have a loader on it. Parts would just be a guess now. I'm quite sure they wouldn't do a gasket and not reman. the head, could be pricey with the way people are doing things now a days. A NH dealer should be able to give you the flat rate hrs. for the job.

The only difference between the 8N flat head and the over head valve engine is several more pieces to R&R in the valve train i.e. rocker arms and push rods watch for any oil lines that go to rocker arms.

HTH,

Tony


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## agmantoo (May 23, 2003)

My concept of where the noise may have originated would be from the flywheel ring gear shearing a tooth. From my experience fluid will either escape through an open exhaust valve or the engine will lock up and stall the starter.


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## FordJunkie (Nov 23, 2007)

True Agmantoo.... but I think he would notice a tooth off the flywheel when cranking unless it fires off really quick. I have had liquid help to close a valve on a race engine, as you say when valve closed rotation stopped, it made a very loud slap as it bent the pushrod and closed the valve.

Tony


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