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Bypassing the back heater in a 1998 GMC Savana?

Hello all,
I’ve already spent much more than most would probably recommend on keeping this van in good, running condition, and after having just dropped $1500 on it last month for a new lower intake, (plus about $1200 last year for a new radiator, et. al.), I’m now faced with the question of repairing the back heater coil, which is sucking coolant out the back end like there’s no tomorrow. First, the back is only used for equipment transport, so the back heat is never even used. I want to just disable the back heat altogether. I’m pretty handy and can do minor repairs/modifications as long as it doesn’t take disassembling the entire front housing in the cab, so my question is this: Is there a way to access the hoses that run to the back heater from under the hood that I can easily just cut and clamp off, or is this a process that would involve getting to the hoses somewhere in the back? Conversely, might this higher mileage, older vehicle benefit from a product such as Bar’s Radiator Stop Leak? I know, I know, it’s just a temporary fix, but I have seen a number of people post online about how they’ve used that particular product and gotten a number of more years out of their vehicle without any more leaks (which is the best I could hope for this vehicle…)? I generally balk at these kinds of products, too, but I’m wondering if I really need to drop $350-400 on just bypassing the back heater, which is what my mechanic quoted me (which seemed very high to me to cut and reroute a hose, at which point I felt I was being taken advantage of…). Thanks in advance, and if anyone knows of a reputable repair shop on the north side of Chicago that could benefit from the money pit that my vehicle is becoming, any recommendations on shops you know and trust would be greatly appreciated.

The heater hoses can be capped off under the hood once you identify them. If you follow the hoses from the front heater back to the engine there will be a branch to the rear heater on each hose. You can use whatever is most convenient to cap off the lines or remove whatever branching device is used.

Thanks, Rod. Any advice on what is best to cap the lines?

Shove a snug fitting bolt in the hose and clamp it.

Leaky heater cores are bypassed with a pipe.

Connect inlet and outlet hoses with a pipe, to be more specific.

connecting the inlet and outlet hoses to the rear heater together may cause the hot coolant to bypass the front heater core.

What I mean was bypassing the rear heater core only.
Connect the hoses for the rear heater inlet and outlet with a pipe, if that’s possible given the layout of hoses.

You, the OP said “I’m pretty handy and can do minor repairs/modifications as long as it doesn’t take disassembling the entire front housing in the cab”, so it shouldn’t be hard for you to locate the hose and connect them together.

The water will tend to take the path of least resistance. That might leave the front heater core with no flow. But maybe not. We may know soon.

From under the vehicle, remove the two heater hoses from the rear heater core. Install a barbed hose coupler such as this to connect the two hoses together and tighten the hose clamps.


A loop would be much better than capped off, to keep the flow going.
You can loop at the back where the tubes become rubber hose. Or you could find the beginning of the tubes near the engine and loop there so the coolant need not even go all the way back there only to come back again.
A parts store may have a pre-bent hose in a U shape to connect the tubes together. It won’t be listed for your vehicle so tell them what your doing.
Auto Zone, O’reilley’s, and Car Quest are helpful that way but stay away from PEPboys !
( pb; "I don’t show to have one of those."
me; " can I look at the hoses you have to see if I can see one I could use?"
pb; NO, no customers behind the counter."
me; "well why don’t YOU go look by my description ?"
pb; "cuz I don’t show to have one!"
me; “well you just lost ten customers, I’ll see to that , g’day mate.” )

Wherever the hoses start in the front of the car for the rear heater, remove one of the hoses. Take the other one and connect it to where the first hose came off. If the second hose is way too kong you can just cut it to a convenient length.

oldtimer 11, There is something I don’t think is right about your Idea.