Weep Holes on Side of 4020 Block

Anonymous-0

Well-known Member
Hi,

I have a 1968 4020 Deere tractor with the diesel engine. Overall, the tractor is solid as hell, and aside from some seeping from quick connect fittings, it is as clean as hell.

I recently did a 12V conversion on the tractor with all modern Deere parts. Working for a John Deere engine distributor sure does have its advantage, and it is amazing that Deere does not change much over the years (the starter went in perfectly for instance,and it was originally for a modern Tier 3 6068).

At any rate, one thing that the modern diesels do not have are the weep holes on the side of the block. I know the history here on why Deere did it, and what the holes are for, but I do have a question that I am having a hard time trying to understand.

When the engine is shut down and has been sitting, things are a little damp on the block below the holes. Two of them (forward and rear holes) have a bit of weeping. The center hole does not.

When I start the engine up, they tend to weep a bit more than when it is shut down (pressure in the cooling system of course). However, after about 20 minutes of running, or until the engine is somewhat warmed up, they completely stop and dry out.

If the seals were going bad, wouldn't they leak all of the time? I cannot imagine that it is simply due to evaporation. I don't go through any antifreeze, and I don't burn or loose any oil. I have had oil scans done, and the oil is perfectly fine. The fluid coming out does not smell like antifreeze, and it is too clean to be engine oil, although it does have a very slight green tinge to it.

So, is it possible that they only weep when it is cold? I am not going to plug them up at all because they do have a purpose. But, my research has shown me that perhaps I might consider a major overhaul... But again, everything looks fine. Could it be just condensation leaking back out? That might make sense since Deere removed them in fear that air might deteriorate the seals.

Any ideas would be greatly appreciated! Thanks!
 
You are over analyzing it. The "O" rings ARE failing, and/or the sleeve is pitted beneath them.

Sooner or later they will leak even worse.

Good, pliable "O" rings on top of good sleeves in these engines do NOT weep. I have a 4020 we re-sleeved in the mid 80"s (which admittedly has NOT seen a lot of HARD work) and the weep hole area is as dry as the day we put it back in service 25+ years ago.
 
If they are weeping, then why is it not antifreeze or oil coming out? And then why does it completely dry up? I checked this morning after running her for about an hour yesterday, and nothing was coming out.

I am not going through any antifreeze, I am not going through any oil, my oil scans show no coolant in the oil, and etc. It doesn't add up.
 
Antifreeze is funny that way it will leak cold and not warm. The green tint of the liquid coming out is antifreeze it would take an eyedropper or less to seep out so you may not notice the radiator getting any lower. If the holes are clean and it were mine I would run it till it got a little worse but keep checking the oil.
 
Ours had some nusiance seepage from there and more from the radiator when really cold.
Some bar's leak seems to of stopped it.
 
Tim,
What the guys are trying to tell you is get ready to do at least an in chassis rebuild. The weep is a prelude to getting worse. Your description is typical to a failing of the O-rings or cavitation has set into the liners. Good Luck!
John
 
Sure it adds up, it just doesn't add up to very much is the deal. There might be just enough antifreeze at a wet weep hole to do the tried and tested method of antifreeze detection that the old timers used. Your tongue. Stick it on the wet part of a wet weep hole and if it tastes sweet then you have just identified antifreeze, be sure to spit it out as it's poisonous. Several times just to be sure it's all gone. Use your spit wetted finger as an intermediary if fuel filters, etc., prevent you from getting in there close enough to use your tongue directly.

As mentioned before you are only minus a few drops and it's way below detection levels.

Once upon a time I went to change oil in a 4640 that I had just roaded some 30 miles and was about to bushog a half section with it. With three buckets ready to catch oil the next morning I unscrewed the drain plug carefully, I was going to throttle the oil flow with the drain plug while I moved buckets under the stream. I got pure green antifreeze at first, but only one half cupful, and rest was all black as tar engine oil. That half cupful wasn't close to the oil pump so it could have accumulated there all winter drop by drop weeping on the coldest days. No harm, no foul. I told the owner, he had no comment.

Sleeves run warmer than the water and warm up first as well. Maybe that's why they dry up.
 

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