I have been called to repair a leaking cooling jacket plug in a large generator on a rooftop. The plug will never be used for anything. I'm thinking either weld the block and plug together or remove the plug and tap to a larger NPT size, but wondering what are other options. The silicone was applied by the customer to temporarily repair it. Sent from my iPhone using Tapatalk Pro
Dont weld it together will be a bigger mess down the road. Remove plug inspect threads on both. look for cracks from overtighting. install new plug if needed with pipe joint sealant or thread tape. just my .02
Thinking of using this: We use it for the pivot shaft seal on 973s. Sent from my iPhone using Tapatalk Pro
plug looks kinda far out no? id be inclined to remove it and check the thread pitches, maybe get a new one just incase so 2 trips arent required and apply thread sealant.. my .02
You surely cant be thinking of welding that plug to a cast block that would be an extremely expensive mistake To start with drain it down pull the plug and find out why its leaking First I would want to know Why is there a new plug in there Why did the old one get taken out pipe threads don't just start leaking I have had enough trouble with Chinese pipe fittings that after checking the whole I would get a good one from a hydraulic supplier along with some good thread sealer
I too would say don't even think of trying to weld the plug to the block. Would like to know why it appears to have been replaced once already. First thing would be to drain coolant and remove plug to check threads, both in the block and the plug. I would also have taken a new plug from some place other than a plumbing shop. Would prefer one from a good hydraulic supply house. Then if threads in block look perfect use a good pipe sealant from the hydraulic supply house or Cat dealer and with everything spotlessly clean reinstall and properly tighten plug. Also looks like the seals on the piston coolers are leaking might want to see if they want the orings replaced on them.
I used to repair propane tanks so I know a thing or two about leaking pipe plugs. High pressure propane is also much harder to seal against than water and extremely difficult to deal with once its placed in service so do it once and do it right. First off from external appearances you have plenty of good material to work with. I was expecting to see a sunken plug. Your pipe plug should be sunk into the casting flush or even a little below. That amount of stickout means there are only about 2 threads sealing. So you might consider tapping it out a little more. However it could be that it is not in there tight enough, either. You might consider using a hex head plug that has a longer threaded area than that socket head one. Also brass might be nice because it is a bit softer which gives you more deformation which is how pipe threads seal. For troublesome threads, I typically take a few careful, tight turns with white teflon tape just behind the first thread. Then carefully fill the valleys with brushed on pipe dope of a good quality. Then turn the thing in tight. Not so tight it breaks something but not like some of these fairies seem to tighten pipe threads. You are squishing the metal together so you keep turning once it gets tight at least one more turn.
Just from one bad experience I'm not a fan of teflon tape on anything threaded in to cast iron. I was hooking up a fuel tank to a D398 Cat Genset. About 8 hours from our shop at a new quarry near Fredericksburg Va.Went to put the fittings in the lift pump on the Cat and used a little teflon tape to seal them up. Turned fitting in till it was just snug, of course it was pointing about 180º away from where I needed it to be. Nice easy turn and just as it was pointing the right direction, POP goes the pump casting! Only thing that kind of saved my butt was back at the shop up in NY was a D379 sitting in parts and the next morning the electricians were leaving the shop to come down and run the wires for the new plant! With this looking like a new plug I have to wonder if this engine had a block heater or something else connected to this point and for what ever reason it was removed and when the fitting that was there was removed no one bothered to run a tap in the hole just to clean out the rust or dirt. Might be all it needs is a little cleaning with a tap and some proper sealant.
The book answer is that teflon tape should never be used for anything because of shards of it contaminating systems, etc. but it is valuable for fittings where the threads are less than perfect and its bulk can help to stop up spiral path leakage. For water fittings I usually use just professional pipe dope from the plumbing supply store because they are no different than water fittings in your house, even less pressure actually. But teflon tape in case there is something wrong with the threads.
My two cents- remove it run a tap through it to clean the crap out of it and install a brass pipe plug and use red loctite. Truck Shop
You don't need a tap, and certainly don't need a bigger size with the amount of that plug that's sticking out. Take that one out, make sure the threads look good, not cross threaded, seized threads, or wrong threads entirely. Use a breaker bar and put it right back in moderately tight and loosen a quarter turn, repeat a couple dozen times and it will wear the threads into each other so they fit better, don't rinse it off until you're done. Then use whatever you want, this isn't an injection pump. I bet you could put the whole roll of teflon tape into that size cooling system and it wouldn't cause any problem.
One other thing I would do is check the other plugs and see if that is supposed to have a straight thread O-ring plug. That could explain why that pipe plug is so far out of the block. Several pipe and ORB threads are close... but pipe plugs WILL NOT seal in an ORB thread. IIRC, Cummins does use some ORB plugs in the QSX/ISX blocks. Not sure on that one.
WOW.....welding that is NO GOOD. It's either cross threaded or the wrong thread pitch. Should be a pretty simple fix.
That's a possibility but I've never seen ORB plugs used on water jacket on Cummins, only oil rifles that I can remember. And until he removes it it's anybody's guess. But there is long reach threaded plugs like that one, maybe that's why it's sticking out so far. It would be nice to know where the problem started. Truck Shop
Yeah, I'm trying to remember for sure. I have a bunch of ORB plugs out of an ISX engine swap in my parts box, but I'm not totally sure if those were oil or coolant plugs. It was back in '09, can't remember if they were out of the oil filter housing or the oil cooler or the water jacket. But I have several different sizes. Also, I cant remember for sure, but it seemed some of those ORB point in the ISX were odd threads. I have Comp-u-chek type quick couplers from -4 to -8 plus bushings, but there was a fuel check point I couldn't access with my fittings.
Could the plug be stainless steel with the thought it wouldn't rust? It looks a little too shiny from plugs I've seen. Not sure if it could happen on cast iron but if the plug is stainless could have galled threads not letting it thread in enough or problems from being dissimilar metals. Stainless fittings often need a lubricant like anti-seize to prevent galled threads. First thing to do is drain the coolant so you can get the plug out. Then make sure what the thread is NPT, straight/ORB , etc. If the threads are buggered clean them up with a steel fitting or a tap. Buying a tap if needed would be cheap insurance on an expensive engine like that. I think with the threads cleaned as long as nothing is cracked, teflon tape or a paste type thread seal would work with the proper plug. If it's cracked might require some more work but get the plug out first.
Now that you mention O ring boss fittings, that second picture does look like it has the bevel where the o ring sits. And the hole next to it is machined. Once the fitting is out and the junk is scraped away, it will be easy to tell now that you know what you're looking for. The surface around that hole will be machined flat like the other one, and there will be an obvious bevel on the top of the threads. If that's a NPT plug in an ORB hole, then the threads will be messed up on one or both if it was threaded more than a couple threads.
Good point there RZ, with all the goop around that plug it is hard to tell if it is in fact machined for the flat surface on top for the oring type plug and plug would need to come out to see if it does have the proper bevel for the oring!:drinkup
was just looking at a parts book from a kt2300 and it shows an oring, nozzle (looks to be some time of adapter) then a plug..
Not seeing the picture you are seeing in the parts book I can only guess that the "nozzle" you are referring to is the piston cooler nozzle. In the picture below I have red arrows pointing to two of them. That black streak under them is why I mentioned checking them as it looks like they are starting to leak. What I believe most of us were thinking the OP was talking about leaking is the plug the blue arrow points to in the picture below with all the silicon sealant around it I'm assuming that is in the water jacket area of the block.
kshansen, found a clearer source and i am mistaken, my apologies. the view was difficult to make out. it appears to be just a plug. i have seen those cheap offshore fittings not fit nicely so this could be as simple as that. sorry for the confusion.