580SE Coolant leaking from fuel injector

[brewer]

As the title says I have coolant leaking from the fuel injector on the number 4 cylinder, only when the machine was running. It was running down the block and dripping probably 3-5 drops a sec, just shy of a steady stream. hadn't noticed any leaking prior to this and the radiator hadn't been loosing any fluid, so I'm guessing the was a sudden fail. Water temp was fine, maybe on the cold side even. Checked the radiator and oil and didn't see any evedence of the 2 mixing in either. I see some engines have a sleeve around the injector that can fail, but looking at the parts manual and maintenance manual it doesn't look like that's the case with this engine. Am I in for a new head gasket or even a cracked head?
I worried now that the cylinder filled up with coolant.

 

[Delmer]

Probably not a head gasket. Probably not a cracked head either, but anything's possible.

Are you sure it's coolant? Wet your hand with water and let it drip in your hand, if it's coolant it will dissolve, diesel will bead up on water, no wait, other way around? Anyway, put some air pressure in the cooling system and test what it is, taste it if you have to, then spit. If you have an overflow tube on the radiator, that's an easy way to add some pressure to the cooling system, the radiator cap will usually function like a check valve.

If you're worried about it filling up with coolant, then don't crank it till you get it figured out. Turn it over two revolutions by hand before cranking. Turn the fan and belt by hand if you can reach them, a little at a time, let the pressure leak down, then a little more.

 

[brewer]

I'm sure its coolant. It left a puddle on my driveway that was ecto cooler green, plus the level in the radiator is down a few inches, so I'll skip the taste test for now. I did smell what had leaked out and didn't smell any diesel in it.

Good thought on rotating the engine by hand. I'll try that today.

 

[Delmer]

Somebody has to have experienced this before, give it some time for responses. That's a case/cummins 4BT 3.9 liter right? A very common engine and the same as a Cummins 5.9 of the same generation, so you should be able to find more info searching by the engine than the backhoe model.

My guess is the injector seals to the head at the bottom of the hole, and there's a weak spot in the casting that has eaten away over the decades from degraded antifreeze and now you have a pinhole leak.

 

[alrman]

@brewer I doubt it will be leaking from the actual injector ..... but I could be wrong.....
I have seen those head gaskets leak like that.
There is a small freeze/welch plug between each rocker cover, take a close look there

 

[brewer]

Delmar - the book lists it as 4/390 not sure if that is the same engine or not. Did a forum search and google search and didn't turn up much. Been reading a lot about "bad" antifreeze I'll probably dump what's in there and replace is with some good stuff. Only had the machine a couple months, who knows what the po put in there.

Alrman - it was a pretty cold night the night before this started leaking, in the low 20's. I went outside and looked real quick between the valve covers - there is some crud in there that looks wet, but I had the little one with me and couldn't really dig into it. I'm thinking you're on to it though, if it was leaking there, the crud on top probably forced it down and around and made it look like it was coming from the injector. Anyway as soon as the boss lady gets home I'm going to run out there with a flash light and see what I see. I'm thinking I hope your right!

 

[Delmer]

Yes, that's the same engine. Alrman forgets more about Case's before breakfast than I'll ever know so I'll take his word for it, except maybe freezing?

Was that the coldest night this fall? It seems too much of a coincidence but still hard to believe it would be freeze damage. The antifreeze would have to be incredibly weak to freeze at "low 20's" and you said it was green. If you don't have an antifreeze tester, they're cheap, or you can tell the strength of antifreeze by rubbing between your fingers, compare it to some 50 50 premixed.

Clean up the area involved and put some pressure in the cooling system. Draining a little and using soapy water to find an air leak is easier than pinpointing fluid sometimes.

 

[brewer]

Alrman Delmar, You guys were spot on. I took a bicycle pump and added some pressure to the rad through the overflow tube and sure enough coolant started coming out the plug. Gotta get the coolant level below the plug to get the coolant to stop coming out. Next chore will be replacing that thing, it's in a tight spot and I don't think I want to take the fuel lines and valve covers out just to give myself more room to work. Any trick to swapping them out?

 

[Delmer]

A small core plug, put a drywall screw through it near the edge. Punch the other side in a bit to loosen it up. Use a pry bar, vice grips etc. to pull the drywall screw. If you can get a prybar at the right angle, you can punch a pry bar through it to.

 

[Billrog]

Some think like this maybe.

 

[alrman]

If I can create some space to make the job easier, then I vote for easier....
Remove the injector lines at least & try not to push the plug into the head.....

 

[brewer]

Thanks guys - when looking for a drywall screw I came across an eye hook that I thought would work well, and probably would have if I exercised a bit of patience.. I put the screw where the pinhole was right in the center of the plug and it just pull straight out. Probably would have worked well if I put it near the edge like Delmer said, but started working on it before I saw the message. I didn't have much time to work on it, and left for vaca. So I have that project waiting for me when I get back. I hope I left enough meat on the plug that I'll be able to put another screw in it.
Age and rust... I once had a simple fuel filter change on my truck that turned into a 3 day nightmare. I'm hesitant to put a wrench on anything that isn't necessary, but I did end up taking out the injector lines which wasn't bad at all.