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Discussion Starter · #1 ·
I have a 4bt in a late 90's Case 1840 skid steer. I have water coming out a hose on the back side of the motor. I have circled in green the part where the hose ties into behind the lift pump. I was adding water to the radiator and noticed a full stream coming out the bottom of the hose (has red arrow). First I thought it might be a rear freeze plug but then saw the full flow coming out of the hose. Is the part in green circle and hose a crankcase vent? Getting ready to pull the head to see if I can see a problem. I just think that a bad head gasket wouldn't cause a full flow out this hose. I think I saw some where that there are freeze plugs behind the big rectangular cover on the side of the block. To get to these freeze plugs, does the injector pump have to come off? Any idea or info is really appreciated. Thanks, Joe.


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Yes, that is the engine breather system. There are 2 freeze plugs behind that panel, however for water to be pouring out of that hose you must have the oil pan full of water too. The source of the problem could be a blown head gasket, cracked block, cracked head, or those 2 freeze plugs. Here's what that side of the block looks like. You will likely have to remove the injection pump to get that side cover off. Not a terrible job. You can access the pump nut through the plug in the front gear housing. Break it loose but don't remove the nut yet. Rotate the engine to TDC position and lock the cam pin on the back of the gear housing. Then remove the pump nut. The pump shaft has a key way and don't loose that down into the gear housing. If you do you'll have to take the front cover off to get it out. Unbolt the pump from the gear housing and set it aside. Don't mess with the shaft so the pump timing isn't messed up. Of course you'll need a new gasket for that tappet cover. When you reinstall the pump remember to unlock that pin on the gear housing once you have the pump bolted back in place. You don't want to tighten the pump shaft nut with that pin locked. You'll break it. If it turns out to be one of those freeze plugs, you might want to replace all of them on the engine while you're at it. If you need part numbers for those plugs I can get that for you. The Cummins number for those behind the tappet cover is 3914035 (Cummins parts manual has an error showing part as 3910435). This part number is for the STORM block only. Older blocks use part 3007635. I see that engine has been rebuilt and don't know if you have the OEM Cummins serial number. If you do I can look on Quick Server and tell you how many of which plugs you need. There are 2 different blocks so need to know which style yours is. If you look at the other side of the block it will have either 2 large freeze plugs or 1 large and 1 small screw in type. The photos below show the 2 styles of blocks.
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1972 F250 4x4, 78 d60, 3.55, np205, 200hp 4bt nv4500 in progress
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I was able to find the Cummins 6bt (dodge 5.9l ) freeze plug kit from Melling at a local parts store. Cheaper and easy to find as compared with buying the stuff from cummins or another route.

Early B series (late 80’s/early 90’s) Shop manual said to use loctite 277 for installing freeze plugs. Which I did, 600 miles on the restore and no problems. I don’t know if loctite changed their formula from then to now, so what was spec back then in the manual might not apply now if formula changed.
 

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Discussion Starter · #5 ·
I was able to find the Cummins 6bt (dodge 5.9l ) freeze plug kit from Melling at a local parts store. Cheaper and easy to find as compared with buying the stuff from cummins or another route.

Early B series (late 80’s/early 90’s) Shop manual said to use loctite 277 for installing freeze plugs. Which I did, 600 miles on the restore and no problems. I don’t know if loctite changed their formula from then to now, so what was spec back then in the manual might not apply now if formula changed.
Thanks, but will the 5.9 freeze plug kit work on a 4bt?
 

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In 1997 Cummins redesigned their engine block somewhat to the version known as STORM. That format did eliminate one freeze plug but as far as I know the sizes of most of the existing ones didn't change. I looked up an early engine before 1997 and here is the list of freeze plugs. As you can see, all the part numbers are the same except those 2 in the tappet gallery. Also, we have a bit of an error. In an earlier post I mentioned those 2 plugs as part 3910435. But on Quick Server those part numbers are 3914035. Cummins has an error in the parts manual where I found that first number. 3914035 is the correct plug on the STORM block and 3007635 is that part on the early style blocks. Can't tell you what difference there is in the 2 part numbers.

3922072 58.06mm expansion plug (4 required)
3007635 1" expansion plug (2 required) these are the 2 in the tappet gallery
3900956 17.73mm expansions plug (3 required)
3900687 expansion plug (1 required)
3920706 expansion plug (1 required)
3900955 expansion plug (1 required)
3900958 32.03mm expansion plug (1 required)

The STORM block 4bt had the following list

3922072 58.06mm expansion plug (3 required)
3914035 expansion plug (2 required) these are the 2 in the tappet gallery
3900956 17.73mm expansion plug (3 required
3900687 expansion plug (1 required)
3920706 expansion plug (3 required)
3900955 expansion plug (1 required)
3900958 32.03mm expansion plug (1 required)
 

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Discussion Starter · #8 ·
Thanks for all the info. I'm getting ready to tear into it. Will update once I can actually see what's behind the tappet panel. I work slow, so it will be awhile. Be back later. Thanks, Joe.
 
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