Coolant leak in passenger floor. Is it possible to bypass the heater core?

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altide8

Active member
I’m getting some coolant in the passenger floor. After investigating I found that the previous owner has bypassed the heater control valve. Now I’m wondering where the coolant could be coming from? I really don’t need the heater to work. So if there is a way to bypass the heater without having to take the heater core out then that would be ideal. Anyone ran into this, or have ideas?


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autostaretx

autostaretx

Erratic Member
It's odd that they bypassed the heater valve, since it defaults to Open if disconnected from driving voltage.

--dick
 
autostaretx

autostaretx

Erratic Member
Looking at the 2006 service manual (section 24, page 76), the heater core is attached to a flat plate holding its pipes, with O-rings as a seal.

HeaterCoreAttach.png

Lots of leakage opportunities.


--dick
 
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DRTDEVL

Active member
autostaretx said:
It's odd that they bypassed the heater valve, since it defaults to Open if disconnected from driving voltage.

--dick
Click to expand...
That all depends on where the van came from. Mine was bypassed when I bought it... from Phoenix, where they didn't need or want the heat to work, but no A/C would have been a deal breaker. Just a long heater hose from the rest pump, over the engine, and to the pipe on the other side.
 
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altide8

Active member
DRTDEVL said:
That all depends on where the van came from. Mine was bypassed when I bought it... from Phoenix, where they didn't need or want the heat to work, but no A/C would have been a deal breaker. Just a long heater hose from the rest pump, over the engine, and to the pipe on the other side.
Click to expand...


I’m in Alabama. So heat isn’t needed at often. Could I bypass the heater core somehow? So I can worry about getting. And replace it later on?


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Last edited:
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DRTDEVL

Active member
If the heat control valve is bypassed, the core is bypassed. One way to be sure would be to take heater hose and run it from the rest pump on the driver's side firewall, run it over the engine, and then to the pipe on the passenger side (where the control valve hose connects).
 
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altide8

Active member
DRTDEVL said:
If the heat control valve is bypassed, the core is bypassed. One way to be sure would be to take heater hose and run it from the rest pump on the driver's side firewall, run it over the engine, and then to the pipe on the passenger side (where the control valve hose connects).
Click to expand...


Would the a/c still work in this case?


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autostaretx

autostaretx

Erratic Member
If you can figure out which hose is the "lower" one at the heater core, that would be the better one to suck on with the vacuum.

--dick
 
Nautamaran

Nautamaran

2004 140” HRC 2500 (Crewed)
Here are a couple of snaps under the hood.

1. Looking up, behind the cabin air filter.
You can replace the “T” with an 90 elbow and go to a union at the bypass valve outlet.
This avoids a hose draped over the engine, and keeps the boost heater available to warm the engine for cold starts.

2. the hose rising from the circ. pump behind the brake booster can be routed over the engine to the bypass valve, but you also bypass the boost heater (if that’s an issue) FAR easier to reach, but more hose length required.

3. The bypass valve. The single hose coming off the front (left) side returns to the engine via a short hard line attached to the block. Either join your new bypass hose to that hard line, or use a union to splice into the existing hose where it was on the valve.

-dave
 

Attachments

A

altide8

Active member
Nautamaran said:
Here are a couple of snaps under the hood.



1. Looking up, behind the cabin air filter.

You can replace the “T” with an 90 elbow and go to a union at the bypass valve outlet.

This avoids a hose draped over the engine, and keeps the boost heater available to warm the engine for cold starts.



2. the hose rising from the circ. pump behind the brake booster can be routed over the engine to the bypass valve, but you also bypass the boost heater (if that’s an issue) FAR easier to reach, but more hose length required.



3. The bypass valve. The single hose coming off the front (left) side returns to the engine via a short hard line attached to the block. Either join your new bypass hose to that hard line, or use a union to splice into the existing hose where it was on the valve.



-dave
Click to expand...


Thanks a ton Dave. I will give it a shot this weekend. Might ask you a few more questions later on when I run into them.


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