This is the 2005, with 5/8 alum tubing heater harness.

1)The way I see the easiest and cheapest is to replace and lengthen the main hot out directly to the hot in front core.

2)Then secure the open hot lines together. Hot source hose (now replaced and ran direct) to the rear core hot tube. Creating effectively a "loop" in the end of that side of the plumbing.

3) leaving the return plumbing as is.

What am I not seeing? Do I need to be concerned about reduced / increased flow?

(I still need defogger / defrost to work).


Ideas I don't think are great.

​​​​​​5) clamping hoses. Only place to is the rear and i want to cut as much heat as possible. Nope.

6) full hose direct hose replacement and unions and clamps for all open lines. Nope.

I think my first idea gets the job done cheaply and just as effectively as idea (6).

 

Just curious- why are you wanting to bypass it? If you’re not getting cold air or it’s not cold enough, it’s an issue with the temp/actuator controls or the AC is undercharged.

Regardless of why, you have options that don’t involve having to add or remove a loop when needed and would only need to be installed in one line rather than both.

1) An electric or vacuum operated shut off valve. Dorman (www.dormanproducts.com) makes several - you’d just need to add the necessary wiring or vacuum lines to make it work.

2) A basic ball valve, available in the plumbing section of a hardware store. Use compression type if you want to splice into the aluminum section; if splicing into the rubber section, you’ll have to get the necessary fittings to adapt a threaded type. There may also be a PEX type available that you can use with regular hose clamps. The closer to the tee in the factory line, the better.

There’s no safety concerns with bypassing the heater core(s) - you’ll just want to verify there’s no leaks after running the engine up to temperature. Cabin heat is merely a perk of using liquid coolant in engines but is not required to keep the engine cool - that’s what the radiator does. However, It is helpful to have cabin heat if the engine starts running hot because the heater core(s) can act as supplemental radiators.

 

Well the reason for the method is to stop the additional heat building up in thermal mass and heating the vehicle.

The AC costs precious money.
Plus the AC has a hole in it I believe. Idk gotta check that next. At least I so far achieved the goal of stopping the heat from pumping all over. I got 2 clamps, a plastic hose union 5/8ths, and a foot of 5/8 heater hose only needing 4-5 inches. $8.50.
i took off the clamps, loosened all the hoses, Trimed and secured the additional extension and then quickly pulled and swapped hoses while plugging the open ends my other finger. Worked ok, I didn't spill much. So little I'll just let the over flow fill it.


It's a traveling van, micro rv n sleeper.
So when you get off the road and need sleep the hot coolant sitting around on a hot night (or day) and having to wait to cool down or deal with it , sucks.

In the winter it's fine and appreciated and have thought about building a larger rear system but then it's gotta get filled with $ antifreeze. Anyways, this van prolly won't see another winter under my ownership. Gotta up grade to one of those 08 and up models with the middle door windows that go down, and a sun roof would be a nice civilized amenity.

 

Yeah I looked around at Home Depot, 5/8ths was highly elusive.

This 'hard wired' method suits my needs better because the disconnect really stops thermal conduction. Heat is still conducting down the coolant on the remaining hose but for $8.50 and the flow is stopped and the in hose is disconnected and sealed, coolant is where it needs to be for fall.. I think I'm sitting good.

I was worried about flow rate regarding limits per heater core but. Idk it's not just the pressure but also the flow pressure / rate that is by design sent to two cores.. there is a regulator on one of the return hoses but F#CK it. If it blows it blows if if don't it don't.

I have one day under the belt and I don't smell any a-freeze or see any moisture on the glass.

 

Fair enough. I hope it works out for you.

 

I used to have an 03 Town and Country that I lived in and yeah, that heat build up was a hassle in the summer.

I have an 01 Caravan now and it's only the heat from the exhaust on the floor I have to worry about now. I am going back to living in it after all this COVID stuff is over, probably next spring so I am using this time to figure out better heat dispersion and insulation.