HELP! Installing freeze plug in rearmost part of motor?

[AndyMan]

I am ONLY getting bubbles in the recovery tank when I flip the cap vent up ( I think I might be introducing air by my own ignorance)... .



When it first happened, I shut it down, waited 15 minutes, turned the key to get a reading from the gauge, then turned the key back off and waited 5 or 10 more minutes. Until it was down to about ~180*. Started, drove 5 miles or so, then shut it down again... waited 20 minutes, then drove it the last 3 miles back to my parking lot at work.



A co-worker and fellow "shadetree" guy rode with me today. In his "professional" opinion, I have a bad gauge/wire/sending unit. He felt like everything else is acting like it should. One other item of note is that he seemed to think the upper radiator hose was too pressurized... maybe a blockage in the system somewhere?



Also, anybody know where the wiring goes from the gauge to the block?

 

[acook]

Andy,

It is not uncommon for coolant to leak out when removing the radiator cap, especially if the engine is warm. Here is a couple of tricks you might try: If you have a radiator pressure tester, put it on the radiator and run the engine up to operating temp and note how much pressure you have. You will have some, but if it keeps climbing you probably have compression in the system. You could also take an empty plastic water bottle, fill it with water, and put the hose from the radiator cap to the overflow bottle in it. Let the engine get to operating temp and look for bubbles (compression). You will see some bubbles as the engine heats up so don't panic. The coolant is just expanding. If there is a constant flow of bubbles, you have a compression leak. Try this at idle and at higher rpm's. Some bubbles maybe present on deceleration.

What about the fan operation? Is it staying locked in and running all of the time?

 

[AndyMan]

Heres another update... of sorts...



first off, it does appear that fan is locked in and running all the time.



Okay. For the time being, I have procured a handful of 2-1/4" rubber expanding plugs. I've lost them all but one, and have it tethered to the block via a small spring. This is so that when/if it pops out, I'll still HAVE it. So I drove the truck back from the field where I left it a week ago. It took a couple hours to go only a couple miles. The plug kept falling out . Once I got it home, I did the test that Anthony (acook) suggested above. I don't seem to have any bubbles being generated. I guess that's a good sign.



Also, The upper hose isn't getting super tight with pressure. Matter of fact, it's not getting stiff at all. That strikes me as kind of strange. Other items of note: Cab HVAC blows out heat, temps get to just over 190*, then fall about 30*. Up and down, up and down. I've read countless posts about that, so it doesn't too much concern me, except that I DID get the latest part numbered thermostat from Cummins a short while back.



To test pressure, here's what I'm going to do. Anthony looked up a part that bolts to the back of the block in leiu of a freeze plug. Evidently in other applications of the "B", they have an air compressor that is liquid cooled. This part, has a fitting to run a cooling line to the compressor. THe fitting is a 1/2" NPT. I'm going to affix the part to my motor, and plumb up a pressure gauge. This will kill two birds with one stone. One: Allow me to get a good pressure reading. Two: fix my freeze plug problem.



synopsis: No bubbles at operating temp, and no signifigant pressure in the upper radiator hose. I nursed the truck home.



I guess I will have to get the part and the pressure gauge to do any furhter diagnosis.

 

[rbattelle]

I'm going to affix the part to my motor, and plumb up a pressure gauge.

I never thought of a coolant pressure gauge... sounds like a nice little project for this winter!



-Ryan

 

[walexa07]

Andy,



A similar thing happened to me this past weekend... ... ... . I lost that rear freeze plug. The freeze plug is cummins part number 3922072, and is 58. 06mm in diameter. I ordered a new one from cummins and it came in today. I also heard about the attachment you mentioned, so I began looking for photos of the rear of 12v cummins. I found a photo for a marine 12v on ebay. There are 2 holes that look to be on the same centerline as the freeze plug. They are threaded... ... ... 12mm x 1. 75. Center distance between the 2 boltholes is 6. 5". DonM from DTR gave me the center distance as well as the bolt hole diameter and pitch. I had the local machine shop cut me a 3" x 7. 5" piece of flatbar... ... . he said it was machined on the side(s). He also drilled two . 5" holes at the center distance of 6. 5". This plate is 1/2" thick, to prevent any distortion from pressing in the new freeze plug. This afternoon, I plan to clean the back of my block with brillo pad, as well as the freeze plug hole, and put some yamabond on the freeze plug and pull it into the hole with this plate. I also plan to put some yamabond on the plate outside where the plug goes so it will also act to seal the hole in case the plug leaks. Leaving it in place, it should keep the plug from ever coming back out. Hope this info helps you out. I may have to grind a little on the bottom side of the plate as I don't know for sure if 3" is going to be too wide, and I will post here what I find.



What I would like to know from you is more info about the plate that the other guy told you about. Do you have a part number? Does it seal to the block with an oring or a gasket, how much is it? If it uses a gasket or o-ring, what are their part numbers? Thanks,



Waylan



One last thing... ... ... if I were you, I would just put a 1/2" npt plug in the plate and hook your pressure tester up somewhere else. The whole cooling system sees the same pressure and it will be easier to unhook your pressure tester if it is plugged in elsewhere. Just my opinion.

 

[Fred Swanson]

Waylan, that is the old part number. The newer one is actually around 58. 10mm. The part number given earlier in this thread is 3900965. Just measured both a few minutes ago, as I have one to do this weekend.

 

[walexa07]

Fred,



Is that the reason that some have had the plugs pop out... ... . because they were the smaller plugs? This whole ordeal has had me totally stumped. It makes me wonder if I have a blown head gasket that only leaks under high rpm or something... ... . leaking so quick to where the radiator cap didn't have time to release the pressure, thus blowing the plug out. I can't find anything wrong like a head gasket leak, but it does have me stumped.



I did install the plug with the cover plate I made that serves 2 purposes... ... . 1 is to install the plug more easily without cocking, and the 2nd was to prevent it from ever coming out again. I used yamabond on the outer edge of the plug to aid sealing, as well as on the plate. Took the truck through a few heat cycles this afternoon, got it up to temp a few times and romped on it and no leaks. I would say it's good now. Anyway, thanks for the info. I think when I change my clutch out I will replace the other freeze plug back there that is inside the bellhousing... ..... anybody ever had that one come out, or does the bellhousing hold it in there?



Waylan

 

[truckstom]

Does anyone know if that part # will work for 24v or is it 12v only?

 

[AndyMan]

Waylan,



The part numbers are as follows (for the cast iron piece, o-ring, plugs, and bolts):

3910495 Flange Head Cap (you will need 2 of theese)

3925226 Water Transfer Connection

3910530 Rectangular Ring Seal (TIP: Use Petroleum Jelly to hold in place)

3008468 1/2" NPT Pipe Plug (you will need 2 of theese)



The total cost of the parts was just under $75. I installed them on Tuesday evening, and I DID have to grind a little bit off the bottom of the "plate" to clear the bellhousing.



I've got the same issue as your (or did have anyway). I'd use those rubber expanding plugs, and they'd hold for a random period of time, then let loose for unknown reasons. THey do seem to pop out ONLY when I'm romping on it. Although some times I romp on it harder than others and it stayed in just fine. Go figure...



I haven't driven it much since putting that plate on. I will report back in a few days.



I like the flat stock plate and the freeze plug you used. Very ingenuitive.

 

[walexa07]

Andy,



Thanks for the response with the part numbers.



I do feel confident with what I put together in that at least if it does begin to leak that it won't be a massive leak. If I ever do have problems again, I will order those parts and install it like you did. Anyway, good luck.

 

[Rhondasway]

I'm going to have to reinstall mine. Any pictures of what you guys did? Is that yamabond similar to/better than JBWeld? I can't get into a big fabricating job or spend a bunch of money; can a person just "glue" a flat plate over the installed/bonded plug? I cannot have this thing popping out again.

Thanks.

 

[walexa07]

Here's what I did and recommend:



I paid the local machine shop $30 to make my plate, but you could easily make it yourself if you have the tools. If not, call your local metal/fab/machine shop and tell them this:



cut a plate 7. 5" by 3" by 1/2" thick. Drill two 9/16" diameter holes along the centerline, with a center distance of 6. 5". Then all you need is two 12mm x 1. 75 bolts, 30mm to 35mm long, and two 12mm lock washers.



Yamabond is what I have used in the past to put engine cases and transmission cases together. It is similar to rtv, except that it is resistant to oil and gas, stays flexible, and makes for a very good seal.



Next, get you a chore boy or similar stainless scouring pad, lay across the passenger's side fenderwell, and scrub the back side of the block, as well as the freeze plug hole until you have covered everything back there good. You want to scrub loose any rust, grime, etc... ... from the block so the plate will pull flat. Next, take some carb cleaner and wet paper towels and wipe it several times to make sure all is as clean as you can get it. Then, put a thin bead of the yamabond on the outer edge of the new freeze plug. Clean the side of your plate that will go against the block, and put a nice bead of yamabond around the plate outside of where the plug will go. Let this set for 15 minutes or so to skin over and begin to dry some so you don't have so much running. You can then set the plug in the block and it should hold itself in place good enough to allow you to put the plate in place and start the bolts. Might want to check fitment of the plate before you begin to make sure there isn't any interference with the bellhousing. It may need minor grinding on the bottom side. Anyway, just snug the bolts up, alternating every couple turns of the bolt and it will pull the new freeze plug into place. I wouldn't recommend doing this without the plug... ..... the plug will should hold the pressure, and the plate is there as backup. Good luck.

 

[AndyMan]

Waylan's way is a little more involved than the way I did it, but is definately cheaper, and arguably better. I have an o-ring seal, he has a true freeze plug and "keeper plate".



Either way would be great Rhonda.



Sorry, no pics. Without pulling the transmission, I couldn't get a camera back there to snap a pic.



BTW, JimFulmer started a thread along these same lines just recently. He's doing something else that's even a little more different than our solutions. Someone over there is also talking about clipping vanes on the waterpump impeller and a high pressure by-pass from EEP... . I've been wanting to check up on that, just haven't in a while. Here's the link: https://www.turbodieselregister.com/forums/showthread.php?p=1444214#post1444214

 

[walexa07]

I'm not convinced that my plate idea is better than Andy's... ..... an o-ring seal is going to be hard to beat. Then you don't have to mess with any gasket sealant or anything. My way would've been way cheaper had I made the plate myself, but I didn't have any material to make it out of, plus was short on time. Either way, at least you have options. When it happened to me, it was all I could do to find bits and pieces of solutions. Good luck and let us know how it goes.



Now I got to get over and read Jim Fulmer's stuff.



Waylan

 

[Rhondasway]

Thanks for all the great detailed info, guys! I actually started on Jim's thread and followed the link here. I'd fixed mine back in November with the help of some high school kids. None of us had done it before and I didn't get it in there exactly right. Even with the head off it's difficult. It's not moving, but does leak a little bit so I won't feel good about it or be able to race until I've replaced it. I'd like put it behind me forever!

 

[Forrest]

I just started following this freeze plug failure by reading a thread on the 3rd Gen site, then I saw you post Rhonda. I was figuring it was a 3rd gen thing only ...



Is this an RPM thing?





tia

 

[walexa07]

Forrest,



Look in the competition forum... ..... there is a thread over there started by Jim Fulmer and it discuss this in depth. The brunt of it all is that it is a high rpm issue for the 12 valves... ..... the water pump pressurizes against the thermostat in high rpm situations up to 80 psi from what I've read and something has to give. EEP sells a kit that bolts onto the back of the block and regulates the pressure down to 45psi, relieving to somewhere else in the coolant system... ..... downstream of the t-stat.



Waylan

 

[Forrest]

Thanks Waylan ... just did ...



Sure would like to do a pop off valve thing.