"Old wrote:

I don't have the later 5J parts book to check but the 3J change to pressure/vacuum vent occurred at s/n 6175 in 1941 so your unit should have that feature unless it doesn't have the original radiator.

The radiator in this one looks almost brand new. I'll give it another look to verify but would the vent be located on the left side rear of upper tank?

Yes, just to the left of the upper hose connection.

"Old wrote:

Yes, just to the left of the upper hose connection.

Ok, I verified and there is nothing there so must be the earlier style radiator, thank you very much for that information.



I removed the left side cover of the oil pan last night and put 10 psi of pressure in the cap. Before pressure I could see a small amount of antifreeze gathered around the lower lip of the the cylinder closest to the back of the engine (#4 ?) but I didn't find any appreciable new amount show up when pressurizing the system. I'm unable to tell if the coolant is coming out from the inside of the sleeve or the outside....yet. When I get more time I'll pull more covers, including valve cover and keep looking.

Thanks,
Jordan

The dreaded drip (liner seal)

"Old wrote:

The dreaded drip (liner seal)

Yeah, that is what I'm seeing but haven't confirmed 100%. Do those take special tools to pull out? I've not replaced a liner seal before.

Thanks,
Jordan

Not really special but does take a disc with correct OD/ID to pull the liner without buggering up the block. Pulling can be done with either threaded rod and nut or hydraulic ram.

"Old wrote:

Not really special but does take a disc with correct OD/ID to pull the liner without buggering up the block. Pulling can be done with either threaded rod and nut or hydraulic ram.

Ok, great. I'm working on tracking down the original service and parts manual's that cover the D3400 so I plan to have those on hand before I dive in to it. So far finding an original service and parts manual has been tough but I've only just started watching for them. I'll go with a re-print if I have to but the quality of the originals is hard to beat and I like to scan them to digital PDF so that I can look at them with out ruining the original and the originals make much nice looking images scanned in than the reprints.

Thanks,
Jordan

If you have a nicely running engine otherwise and especially if you haven't had a chance to run the tractor to really check it out other than the engine, I would dose it with stopleak in the radiator and run it. I guess it is my favorite dead horse to beat, but I stopped leaking liner seals that I created by washing the sediment away from the lower liner area of the water jacket on our D6. The leak was so bad you could watch the level of water fall in the radiator tank and I had water shooting out of the dipstick tube when I pulled it!

I drained the block and then the water from the bottom of the oil pan and replaced the plug when I started getting oil. Then I pumped a bottle of DIKE mixed with a gallon of old coolant into the block through the drain port on the side of the block, replaced the plug and let it sit overnight. The next day I drained the water from the oil pan again, filled the radiator with coolant and ran it until it was good and warmed up before changing the oil. The new oil stayed black and there was no moisture collecting in the crankcase for a couple years.

When it began to show some moisture accumulation, I thought it was surely the seals leaking again and was planning on swapping the engine, overhauling it or scrapping the whole tractor when I discovered the leaking freeze plug under the valve cover. Replaced those and it stayed dry for a couple more years until the new owner ran it with fuel diluting the oil and it threw a rod. I am in the process of swapping the engine, but the replacement isn't looking promising so far!

I've considered using a coolant sealer, especially since this system it sounds could be run with a vented cap so it wouldn't build pressure? The leak is very slow, probably 1/2 a cup a day if that and I could hardly get it to do anything even with 10 psi in the radiator.

My main concern is that it's an internal leak so there would be potential for the leak stopping solution to enter the oil and possibly harm bearings or plug passages. I've heard stories of Bars Leak doing that. Do you know if DIKE would be safer to use? I would assume, like I said since the leak is so minor it would probably stop it completely right away but the idea of toasting all the bearings trying a quick fix scares me.

Thanks,
Jordan

Dike itself is supposed to be safer for bearings if it gets in the oil, but the main thing is to stop the coolant leaking. I had thought of using just water right at first, but someone told me the DIKE needs the antifreeze in the coolant to work, so it got regular green antifreeze.

We used Dike in a DT466 engine for a year or more for radiator leaks and ended up doing an inframe overhaul when it got coolant in the oil. After the inframe it was not long before coolant was discovered in the oil again. Dropped the pan and pressurized the system and discovered that there was a pit corroded through the rear of the waterpump housing that had probably been the problem all along. The engine was running about 8 hours a day through all of this and its still running today.