Hi all, long time member 1st time poster. I have a 2007 jinma 284 with a coolant leak. Noticed a leak coming from the water pump area. Thought it was the water pump leaking out the weep hole. After pulling the the pump the pulley didn't show signs of a bad seal. Did notice coolant coming from a cavity behind the water pump and at the bottom of where the pump sits. See photos. Any ideas what that cavity is or why there would be coolant leaking from there would be greatly appreciated.
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piper184
Platinum Member
I'm pretty sure that is a soft plug in the front of the block.
You are going to have to pull the timing cover, gears and case to get at it.
Before I went to all that work, I would try and fix up a plate for the water pump opening and block off the rad hoses. Then put some pressure into the block to see if you can confirm a leak at that plug.
Do you have a parts manual for the engine? If not, several dealers have them online for you to look at.
You are going to have to pull the timing cover, gears and case to get at it.
Before I went to all that work, I would try and fix up a plate for the water pump opening and block off the rad hoses. Then put some pressure into the block to see if you can confirm a leak at that plug.
Do you have a parts manual for the engine? If not, several dealers have them online for you to look at.
Bob Rooks
Elite Member
I agree with Piper. That's a cup type core (casting) plug. But I would clean that area thoroughly to make sure it's necessary to pull off the front of the engine.
Bob Rooks
Elite Member
I would bet on corrosion since it's been in there for so long. Corrosion can be caused by several ways, lack of coolant treatment (no anti-freeze or conditioner), electrolysis, impingement........Thanks for the reply. What would cause the plug to fail?
piper184
Platinum Member
Yes, most likely corrosion of some sort. Most plugs last the life of the engine, but stuff happens.
There is a remote possibility that in cold temps and little or no anti-freeze, ice forming in the block can push out a plug.
That does not appear to the the case here as I can see the coolant is green. Also the plug is trapped in the hole by the timing case so it couldn't have moved very far. If none of the other plugs show any signs of distress you can easily rule out freezing as the cause.
I am curious about how many hours are on your tractor. My 2006 284 has 1000 hours on it. My water pump seal failed at about 700 hours. For expedience I slapped a new pump on it and moved on. The old pump is in my pile of things to do. Someday I will attempt to take it apart and see if it can be "rebuilt" if I can find seals. Someday...
There is a remote possibility that in cold temps and little or no anti-freeze, ice forming in the block can push out a plug.
That does not appear to the the case here as I can see the coolant is green. Also the plug is trapped in the hole by the timing case so it couldn't have moved very far. If none of the other plugs show any signs of distress you can easily rule out freezing as the cause.
I am curious about how many hours are on your tractor. My 2006 284 has 1000 hours on it. My water pump seal failed at about 700 hours. For expedience I slapped a new pump on it and moved on. The old pump is in my pile of things to do. Someday I will attempt to take it apart and see if it can be "rebuilt" if I can find seals. Someday...
I agree with Piper. That's a cup type core (casting) plug. But I would clean that area thoroughly to make sure it's necessary to pull off the front of the engine.
What would other symptoms be other than the visual leak? I was using it to move 5x4 round bales to feed our animals with no issues except the temp gauge didn't show a temp rise. Outside air temps were in the single digits at the time. Thanks
Bob Rooks
Elite Member
Sometimes temp gauges can fool you. The bulb of the sending unit or cap tube must be submerged in the flow of coolant to be accurate. If the coolant is not present or flowing any reading would be unreliable. Operating in single digit conditions would require blocking the airflow (a common practice) through the radiator by at least half to prevent freezing. Wind chill through the radiator from the fan could easily see sub-zero conditions. Reverse logic applies here because you want to keep the radiator and air flow as warm as possible. So, did the front of the engine actually freeze? I don't know.
Also, when the ambient temps reach 10°F diesel fuel will begin to gel, unless you are really lucky. Something you really don't want. An additive is mandatory.
Also, when the ambient temps reach 10°F diesel fuel will begin to gel, unless you are really lucky. Something you really don't want. An additive is mandatory.
If the soft plug ( is that the same as a freeze plug?)is the problem how difficult a job is it to fix it? I am mechanically inclined but not too knowledgeable about diesel engines.Sometimes temp gauges can fool you. The bulb of the sending unit or cap tube must be submerged in the flow of coolant to be accurate. If the coolant is not present or flowing any reading would be unreliable. Operating in single digit conditions would require blocking the airflow (a common practice) through the radiator by at least half to prevent freezing. Wind chill through the radiator from the fan could easily see sub-zero conditions. Reverse logic applies here because you want to keep the radiator and air flow as warm as possible. So, did the front of the engine actually freeze? I don't know.
Also, when the ambient temps reach 10°F diesel fuel will begin to gel, unless you are really lucky. Something you really don't want. An additive is mandatory.
piper184
Platinum Member
Frost plug, freeze plug, soft plug, all the same thing. Some are a domed disk that you put in with the dome facing out, then strike the dome to flatten it somewhat causing it to seal against the wall of the hole. It seems to me that these have fallen out of favor the last few years. The other style is a cup shaped disk that you put in with the cup facing out. The outer walls of the cup are slightly tapered so it is larger at the open end. You drive these cups into the hole so that the open end faces out.
The style you have is the cup style. They are the easiest to install and get a good seal.
To remove either style, you drill a hole in the center large enough to insert a pry bar of some kind and lever it out of the hole. Some people use a slide hammer that uses a sheet metal type screw on the end. Drill a pilot hole, thread in the screw and then slide the hammer to tap it out.
Carefully clean the bore of the hole and use emery cloth to polish out any burrs. I believe that there are sealing compounds (like loc-tite) that can be used on the new plug to insure the seal.
If this were my project and I wasn't racing the clock for some reason, I would pull the radiator and remove the radiator support. You already have the fan and pump out of the way so you have a good start. Then pull the timing cover, internal parts and finally remove the timing case to gain access to the plug.
Then replace the plug and reverse all the steps. New gaskets and seals as you go. At this point I would probably replace all the hoses and thermostat, just because they are so much easier to do with all the other stuff out of the way. I would also try my best to flush the block and radiator at this time. Fill with water and test for leaks if all is well, drain and refill with the appropriate coolant mix.
This is a fair amount of work, but none of it is very complicated. Removing the old plug will probably be the most challenging part. You want to be really careful not to cause any scratches or other damage to the inside of the bore hole of the block. That would make it really hard to get a good seal with the new plug.
But as I said earlier, I would spend some time figuring out how to put some pressure into the coolant side of the block (5 to 10 psi) and make sure there was fluid above that plug. With pressure in the block you should be able to easily confirm that it is indeed the plug that is leaking. Clean and dry with an air hose first to make darned sure that is where the leak is before committing to all that work. The reason I say this is that in that location, the cup of the plug is acting as a small dam that could just be catching output from a leak elsewhere and allowing it to puddle up against the plug, making it look like the plug is leaking when all it is really doing it holding the fluid in place.
Best of luck. Take lots of pictures as you go and if you get stuck, don't be afraid to ask questions. That is why this forum exists.
The style you have is the cup style. They are the easiest to install and get a good seal.
To remove either style, you drill a hole in the center large enough to insert a pry bar of some kind and lever it out of the hole. Some people use a slide hammer that uses a sheet metal type screw on the end. Drill a pilot hole, thread in the screw and then slide the hammer to tap it out.
Carefully clean the bore of the hole and use emery cloth to polish out any burrs. I believe that there are sealing compounds (like loc-tite) that can be used on the new plug to insure the seal.
If this were my project and I wasn't racing the clock for some reason, I would pull the radiator and remove the radiator support. You already have the fan and pump out of the way so you have a good start. Then pull the timing cover, internal parts and finally remove the timing case to gain access to the plug.
Then replace the plug and reverse all the steps. New gaskets and seals as you go. At this point I would probably replace all the hoses and thermostat, just because they are so much easier to do with all the other stuff out of the way. I would also try my best to flush the block and radiator at this time. Fill with water and test for leaks if all is well, drain and refill with the appropriate coolant mix.
This is a fair amount of work, but none of it is very complicated. Removing the old plug will probably be the most challenging part. You want to be really careful not to cause any scratches or other damage to the inside of the bore hole of the block. That would make it really hard to get a good seal with the new plug.
But as I said earlier, I would spend some time figuring out how to put some pressure into the coolant side of the block (5 to 10 psi) and make sure there was fluid above that plug. With pressure in the block you should be able to easily confirm that it is indeed the plug that is leaking. Clean and dry with an air hose first to make darned sure that is where the leak is before committing to all that work. The reason I say this is that in that location, the cup of the plug is acting as a small dam that could just be catching output from a leak elsewhere and allowing it to puddle up against the plug, making it look like the plug is leaking when all it is really doing it holding the fluid in place.
Best of luck. Take lots of pictures as you go and if you get stuck, don't be afraid to ask questions. That is why this forum exists.
Bob Rooks
Elite Member
Yes, the same, but they aren't really "freeze plugs". Many blocks have cracked because the core plugs didn't pop out. They are casting core plugs that are used to remove casting sand from the manufacturing process. They aren't difficult at all to replace, same as in a car engine, but what adds to the difficulty is the access to them. In your case though, it looks like you may have to remove the timing gear case cover. This would not be unlike doing the job on a Chevy or Ford where you would have to remove the radiator and some other interferences.If the soft plug ( is that the same as a freeze plug?)is the problem how difficult a job is it to fix it? I am mechanically inclined but not too knowledgeable about diesel engines.
Sorry for my ignorance, but if the plug is behind the timing gear case, why is the water coming out above that location? Wouldn't the water seek it's lowest level, that being the plug as it is lower than the pictured cavity? I'll try to pressurize as piper 184 recommended and see what happens.Yes, the same, but they aren't really "freeze plugs". Many blocks have cracked because the core plugs didn't pop out. They are casting core plugs that are used to remove casting sand from the manufacturing process. They aren't difficult at all to replace, same as in a car engine, but what adds to the difficulty is the access to them. In your case though, it looks like you may have to remove the timing gear case cover. This would not be unlike doing the job on a Chevy or Ford where you would have to remove the radiator and some other interferences.
Bob Rooks
Elite Member
My apologies. I don't think I knew that. So the leak is above the coolant pump?
The leak is coming from that cavity behind the water pump but it seems to be above the timing gear assembly. Could it be that it's got a leak at the head gasket and it's working its way down to that cavity somehow? The head gasket had been replaced a while ago. The hour meter stopped working at 164 hours so it's been broke for a while. I'm out of town for a week and not able to investigate much more. I'll jump back on the thread when I get back into town.My apologies. I don't think I knew that. So the leak is above the coolant pump?
piper184
Platinum Member
That cavity has the soft plug in it. My bet is the plug is rusted through and it is leaking. The coolant pools up against the back side of the timing case until it reaches the top, then flows out over the case.
Do you have a parts manual for the engine?
If not, tomorrow I can scan the page from mine and post it here.
Do you have a parts manual for the engine?
If not, tomorrow I can scan the page from mine and post it here.
That would be greatly appreciated. Thanks.That cavity has the soft plug in it. My bet is the plug is rusted through and it is leaking. The coolant pools up against the back side of the timing case until it reaches the top, then flows out over the case.
Do you have a parts manual for the engine?
If not, tomorrow I can scan the page from mine and post it here.
piper184
Platinum Member
Actually here is a better image than I can scan:
Cylinder Block & Flywheel - Y385 Engine
The plug you need is #43 in the image. Just hover over it with the mouse and it will auto zoom in. Interestingly, there is no part number listed for #43, but the part number for #29 is the same as #43 from my printed manual. Y480G-01109
The next page you will need to look at is here:
Timing Gear - Y380 Engine
Even though it is listed as the Y380 engine from what I can tell the part numbers are the same as from my Y385T book.
From what I can see, you will need to take all pieces out of the timing gear housing in order to remove the housing so that you can get to that plug. It is unfortunate that it is designed that way but the casting process may have left them no alternative.
Unfortunately for you, that means removing the hydraulic pump on the right side and the injection pump on the left side. All the gaskets and seals will need to be replaced as well.
Take lots of pictures as you go and make witness marks on everything so you can get it back exactly the same as it was.
It might not hurt to give them a call at Circle G or Affordable Tractors to make sure they have all the parts you need and maybe get some advice from their service departments. They both have good reputations. Another good place is Ranch Hand Supply although last I checked they did not have much information online.
Cylinder Block & Flywheel - Y385 Engine
The plug you need is #43 in the image. Just hover over it with the mouse and it will auto zoom in. Interestingly, there is no part number listed for #43, but the part number for #29 is the same as #43 from my printed manual. Y480G-01109
The next page you will need to look at is here:
Timing Gear - Y380 Engine
Even though it is listed as the Y380 engine from what I can tell the part numbers are the same as from my Y385T book.
From what I can see, you will need to take all pieces out of the timing gear housing in order to remove the housing so that you can get to that plug. It is unfortunate that it is designed that way but the casting process may have left them no alternative.
Unfortunately for you, that means removing the hydraulic pump on the right side and the injection pump on the left side. All the gaskets and seals will need to be replaced as well.
Take lots of pictures as you go and make witness marks on everything so you can get it back exactly the same as it was.
It might not hurt to give them a call at Circle G or Affordable Tractors to make sure they have all the parts you need and maybe get some advice from their service departments. They both have good reputations. Another good place is Ranch Hand Supply although last I checked they did not have much information online.
Thanks for all the info and links. I'll pressurize when I get back to it later this week.Actually here is a better image than I can scan:
Cylinder Block & Flywheel - Y385 Engine
The plug you need is #43 in the image. Just hover over it with the mouse and it will auto zoom in. Interestingly, there is no part number listed for #43, but the part number for #29 is the same as #43 from my printed manual. Y480G-01109
The next page you will need to look at is here:
Timing Gear - Y380 Engine
Even though it is listed as the Y380 engine from what I can tell the part numbers are the same as from my Y385T book.
From what I can see, you will need to take all pieces out of the timing gear housing in order to remove the housing so that you can get to that plug. It is unfortunate that it is designed that way but the casting process may have left them no alternative.
Unfortunately for you, that means removing the hydraulic pump on the right side and the injection pump on the left side. All the gaskets and seals will need to be replaced as well.
Take lots of pictures as you go and make witness marks on everything so you can get it back exactly the same as it was.
It might not hurt to give them a call at Circle G or Affordable Tractors to make sure they have all the parts you need and maybe get some advice from their service departments. They both have good reputations. Another good place is Ranch Hand Supply although last I checked they did not have much information online.
