4020 cab heater

[ster1]

My "info" comes from several different sources, one copy of a different Deere engine on Issu. That was the first manual I referred to, and it was a crummy picture, and most likely close but not exactly what I have. The other source I have is a 4020 manual on scribd, which is a hassle to get back to the right page (it took forever to get through all the ads). It didn't have a diagram in it, but described the flow as going from the pump to the head, down through the block and back up through the bypass. Then the Tstats open, and flow diverts through the rad. There's also a bunch of other threads like this, and more than one suggest connections like I have. I did try to gather existing info before posting up another thread. There is (was) an OEM option for a cab and heat, but mine isn't that, so I'm hoping for another option. Anyway, I guess nobody's actually done this before. I was really hoping for someone who'd actually done it and could tell me what I did wrong. Thanks anyway.

 

[Tx Jim]

You said that already . I'm looking for something a little more specific. Thanks though.

Evidently you didn't open/view the link I posted on Feb 13 @ 6:11AM CST that contained a photo showing how JD engineers elected to attach heater hoses to JD 4020 engine. Shown below is the photo from that link.

 

[ster1]

Evidently you didn't open/view the link I posted on Feb 13 @ 6:11AM CST that contained a photo showing how JD engineers elected to attach heater hoses to JD 4020 engine. Shown below is the photo from that link.

Yes I did. And I asked you some questions about your comment, but you didn't respond. Not that it matters though. I'm looking for info from someone who actually has knowledge of this modification specifically, not general / theoretical. Thanks though. By the way, I noticed you posted the exact same thing on my thread on another forum. You'll get the same answer there.

 

[Scott 730]

Yes I did. And I asked you some questions about your comment, but you didn't respond. Not that it matters though. I'm looking for info from someone who actually has knowledge of this modification specifically, not general / theoretical. Thanks though. By the way, I noticed you posted the exact same thing on my thread on another forum. You'll get the same answer there.

Wow. Jim is one of the most knowledgeable and respected JD people on here. Don't bite the hand that feeds you comes to mind.

 

[rockcreek4630]

Just so I understand, you're thinking I need to re-route the block heater output hose to the right side of the engine and T it into the cylinder head where I have the ball valve? I don't understand.

My thinking is the coolant is flowing through the block heater and not your cab heater. Easy to test clamp off the upper hose on the block heater and see if you get cab heat.

 

[Tx Jim]

Yes I did. And I asked you some questions about your comment, but you didn't respond. Not that it matters though. I'm looking for info from someone who actually has knowledge of this modification specifically, not general / theoretical. Thanks though. By the way, I noticed you posted the exact same thing on my thread on another forum. You'll get the same answer there.

Sorry I thought photo in link I posted was self explanatory but I suppose not. If you ask same question on a different forum why would you think the reply if correct made by same poster(ME) would be any different?

I think the reason your tractors heater won't operate is due to how engine coolant heater & cab heater are attached together on engine because circulating coolant is going to take the path of least resistance.

I hope you have a nice day, Jim

 

[Tx Jim]

Here's a link I located on this forum from 15 yrs ago that addresses the cab heater coolant supply issue. https://forums.yesterdaystractors.com/threads/4020-cooling-pressure.602629/

 

[ster1]

Thank you, I read through it and he's having (had?) the same trouble I am. Unfortunately he's no longer active on the forum, so I don't think I can reach out to ask how he solved it.

 

[Tx Jim]

You're welcome
Well to me that link confirms what I've been stating that you need to add a hose barb to line by thermostat housing or get correct line from tractor salvage yard. Conversations in that link that I posted earlier refer to a line similar to line in photo below

 

[buickanddeere]

Is this diagram in a factory manual? Can you take a photo of it and post it? I am deducting the the coolant system major flow pattern must enter the front of the head on one side then it is forced down on that side into the block. Then flows up out of the block on the opposite side up through the head out to the thermostats. Where it exits to the radiator. That means that the connection to the head is on the wrong side of the head. It should be one the left side where the coolant exits to the thermostats. This is based solely on “how I think it works” so I could be dead wrong.

Into the front of the block , back through the bloc and up through the head into the stats and coolant manifold.

 

[used red MN]

Into the front of the block

I would love for you to tell me how that works, refer to photo. That screen shot is of the photo of the front of a 4020 404 replacement block for sale, I linked in reply 19.

 

[Tx Jim]

It's not a thermo-syphon, it has a pump. It's active or forced circulation.

As I previously implied in your tractors photos coolant is forced through a "Y" taking path of least resistance not traveling several feet into the air to the top of cab where heater core is located!!!!!!!!!!!!!!!!!!!!!!! Water pump can only pump coolant ""UP to heater core"" if coolant is correctly routed to heater core without a """"Y"""" leading from to tank heater

 

[buickanddeere]

As I previously implied in your tractors photos coolant is forced through a "Y" taking path of least resistance not traveling several feet into the air to the top of cab where heater core is located!!!!!!!!!!!!!!!!!!!!!!! Water pump can only pump coolant ""UP to heater core"" if coolant is correctly routed to heater core without a """"Y"""" leading from to tank heater

The cab heater flow would have a modest assist in flow . From the hot coolant rising and the cooler coolant dropping .

 

[Tx Jim]

Do you think the hot coolant temperature would be enough heat to cause coolant to rise several feet up to heater core rather than take easier route through the "Y fitting"?

 

[buickanddeere]

Do you think the hot coolant temperature would be enough heat to cause coolant to rise several feet up to heater core rather than take easier route through the "Y fitting"?

Not going to make a significant difference when properly plumbed . however with some Jimmy rigged connections . Convection is probably the primary source of flow .
I am not sure how sending coolant from a hot high pressure location on the side of the head or from a coolant manifold port below the stats to the cab . Then returning the cab heater coolant to the suction side of the coolant pump . Could be a mystery .
No idea what the fascination is with the bypass line.

 

[Tx Jim]

Not going to make a significant difference when properly plumbed . however with some Jimmy rigged connections . Convection is probably the primary source of flow .
I am not sure how sending coolant from a hot high pressure location to the cab . Then returning the cab heater coolant to the suction side of the coolant pump . Could be a mystery .
No idea what the fascination is with the bypass line.

Factory JD heater hose connections didn't include a "Y" that included engine coolant heater. One hose was attached to water pump & other hose was attached to engine cylinder head. Water pump in combination with hot coolant aided in coolant traveling "UP through heater core".

 

[Fixingfarmer]

Factory JD heater hose connections didn't include a "Y" that included engine coolant heater. One hose was attached to water pump & other hose was attached to engine cylinder head. Water pump in combination with hot coolant aided in coolant traveling "UP through heater core".

The water pump might not have the lower #12 on the original parts page sticks out bottom rh side (I believe) of water pump if there was no heater no one would have driven in the lower pipe. I believe I’ve skipped it before since 9 out of ten of these don’t have cabs.

Easy enough with all the coolant out then the bypass top line can go to the block through the block heater and life is all better….

So to get to that return pipe however he’s going to have to pull the hood off to access the fancy double thermostat housing and likely the cab is going to make that more fun.

Return hose shouldn’t matter too much I’d probably move the y to the other side of the block heater and call it good if I was doing it dump it back to the block IMO as long as the supply is off the water pump down below

You wouldn’t think there would be a restriction through that block heater but often there’s a small pump inside so could be I guess if something got stuck or…

Heater valve in the cab itself I haven’t ever had the joy of working on that either so that might be something that would stop flow

 

[buickanddeere]

The water pump might not have the lower #12 on the original parts page sticks out bottom rh side (I believe) of water pump if there was no heater no one would have driven in the lower pipe. I believe I’ve skipped it before since 9 out of ten of these don’t have cabs.

Easy enough with all the coolant out then the bypass top line can go to the block through the block heater and life is all better….

So to get to that return pipe however he’s going to have to pull the hood off to access the fancy double thermostat housing and likely the cab is going to make that more fun.

Return hose shouldn’t matter too much I’d probably move the y to the other side of the block heater and call it good if I was doing it dump it back to the block IMO as long as the supply is off the water pump down below

You wouldn’t think there would be a restriction through that block heater but often there’s a small pump inside so could be I guess if something got stuck or…

Heater valve in the cab itself I haven’t ever had the joy of working on that either so that might be something that would stop flow

Why dump the cab heater return line back into the portion of the block that is pressurized by the pump ?

 

[Fixingfarmer]

Why dump the cab heater return line back into the portion of the block that is pressurized by the pump ?

Return might be the wrong word for me to use that’s my fault.

For sure that drive in fitting on the pump is what’s for a heater though. I can’t remember if the drive in fitting is on the lower coolant side of the pump (intake) I believe so.

Plumbing it from the thermostat housing or the block pressure wise shouldn’t be different once it’s warmed up there shouldn’t be much difference. It might heat up quicker in the cab if plumbed in the block side into his Y since otherwise it would get pulled through radiator.

 

[buickanddeere]

Return might be the wrong word for me to use that’s my fault.

For sure that drive in fitting on the pump is what’s for a heater though. I can’t remember if the drive in fitting is on the lower coolant side of the pump (intake) I believe so.

Plumbing it from the thermostat housing or the block pressure wise shouldn’t be different once it’s warmed up there shouldn’t be much difference. It might heat up quicker in the cab if plumbed in the block side into his Y since otherwise it would get pulled through radiator.

The heater supply connection made on the thermostat manifold . Would be better
On the engine side of the stats vs the radiator side of the stats.
More pressure thus more flow . Plus there
would be some heat as the engine is warming up .