# Coolant leak JD 4100



## Roberts 4100 (14 d ago)

Hello,
I have a 4100 that has developed a coolant leak. It appears to be leaking from under and behind the fan. I can't locate the exact spot. I'm thinking it's the water pump, but I would like some confirmation from the experts here before I buy one and get into replacing it. Thanks in advance.

I looked at it again today. It appears to be leaking from a "hole" in the water pump. It looks like it's supposed to be there, it's on the fuel filter side of the engine. It's never leaked before. Any ideas? Any thoughts, advice would be appreciated.

Thanks


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## The 203 (Apr 27, 2020)

Coolant dripping from that hole tells you the seal is failing. It could leak slowly for a long time before blowing out all at once. I would look at a water pump or rebuild it if you can.
Overheating can do damage very quickly if you don't watch gauges or warning lights. You probably know that.

Verify that it is coming out of that weep hole before buying a pump. Coolant leaks follow odd paths running down an engine. A hose leak at the upper radiator hose for example will often run down the water pump to the area of the weep hole.


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## Roberts 4100 (14 d ago)

Thanks for the reply. I really appreciate it. 

I ran it today and watched the weep hole. I only ran it for about 5 minutes and it didn't leak until I shut it off. It definitely was coming out of that weep hole. You think replacing the pump will solve this?

Thanks again.


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## The 203 (Apr 27, 2020)

Roberts 4100 said:


> Thanks for the reply. I really appreciate it.
> 
> I ran it today and watched the weep hole. I only ran it for about 5 minutes and it didn't leak until I shut it off. It definitely was coming out of that weep hole. You think replacing the pump will solve this?
> 
> Thanks again.


Yes, youur pump seal is leaking. The new pump is a complete unit that will include the leaking seal
Here is a link to a JD 4100 pump but you may find a much better price elsewhere. Hopefully!
Thats a pricey water pump
New Water Pump for John Deere 2210 4100 4110 455 670 F925 F932 F935 AM881433 | eBay


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## Roberts 4100 (14 d ago)

Thanks for your help.


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## thedukes (Jan 9, 2022)

The above info sounds correct in my experiance.

Weep hole is there for a reason.......I'm surprized they still exist.


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## Roberts 4100 (14 d ago)

Thanks. I'll get a pump on order today. 

Have you replaced one? Is there anything difficult about it or just take everything apart, replace the pump, and put it all back together the same way it was taken apart?
Any advice would be greatly appreciated. 

Thank you!


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## The 203 (Apr 27, 2020)

I'm not familiar with a JD 4100 but just assemble the reverse of disassemble. If you remove any bolts and coolant comes out of the tapped bolt hole, use some RTV or similar sealer on the bolts threads when you reassemble. Just on the threads not on the end of the bolt.
Taking a couple photos prior to disassembly helps show how all the brackets bolt back on helps. Our phone cameras are a valuable tool for jogging the memory. Mine is getting old!


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## Roberts 4100 (14 d ago)

That's great! I can do that. I'll get new hoses and belts while I'm at it. I'll use the camera as you suggest, this old memory doesn't work like it used to either and I don't want to have a bunch of parts left over when I'm done. 

Thanks!


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## jd110 (Nov 23, 2015)

Might want to consider a thermostat also since it is mounted in the water pump housing as well. Also will need a thermostat gasket.


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## Roberts 4100 (14 d ago)

Thanks. I'll do that too. I'll be in there anyway. I may as well do all of it.


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## thedukes (Jan 9, 2022)

Pay attention to length of different bolts.......
Pics , draw diagram
put old bolts in respective holes of New pump as you remove them
draw a stencil of waterpump on cardboard and poke holes for bolts ...place bolts in holes as you remove them.


lots of ways..just pick one


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## Roberts 4100 (14 d ago)

Thanks. I like the cardboard template idea, I'll do that.


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## Roberts 4100 (14 d ago)

So I went to the local JD dealer today to order the pump. All that is offered is the whole pump assembly for close to $500. Anyone have success with ordering JD parts from other sources? Any info would be appreciated. 
Thanks


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## thedukes (Jan 9, 2022)

Go to jdparts.com

enter your tractor model

click on compact 4100

then engine

then section 11.......waterpump /fan etc

Looks like part # 8 is a pump kit.......no price listed unless you log in.

Might look at the ebay options but this diagram will show in general what you are dealing with.



https://partscatalog.deere.com/jdrc/sidebyside/equipment/72197/referrer/navigation/pgId/11598754


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## Roberts 4100 (14 d ago)

Thanks. That #8 is also what I found and is what the dealer quoted at $468. I saw some pumps on eBay and Amazon in the $200 range, it's just had to tell if they're the right one. I'm inclined to try from Amazon because of the easy return policy. I'm waiting to hear from one of their sellers to see if the one I found is the correct one for my tractor. 

Thanks for all of your help.


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## thedukes (Jan 9, 2022)

Maybe buy just the gasket from JD if its cheap.......Then you would have a pattern to match up to whatever cheap pump you could find.

If your JD dealer was really nice He'd just let you trace it on a piece of paper assumming one was in stock.

Only other choice is to press the old one apart and try to find replacement seals/bearings somewhere.
I've heard of folks doing this. At one time you could buy all the individual parts of these kits.

Good luck


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## Roberts 4100 (14 d ago)

I'm close enough now. I'll figure it out. I'll spend the $500 if I have to. It's been a good machine and hasn't cost me much over the 15 years I've had it. 

Thanks again


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