[Cap'n P.Zazz]

Anyone have a list of ALL the hoses in the engine compartment? I know there is upper, lower, U at water pump, and for the heat isn't there 4?

 

[Mariosaab]

4 heater hoses? So me bypassing the heater core with the 2 that go into the firewall does do anything for my coolant leak? Where are the other 2 hoses for heater

 

[Cap'n P.Zazz]

 

[Cap'n P.Zazz]

Also on that list should be the two hoses to the throttle body, and I believe 1 hose from the resovoir to the radiator. The rest are metal, to/from Turbo and water pump

 

[Cap'n P.Zazz]

4 heater hoses? So me bypassing the heater core with the 2 that go into the firewall does do anything for my coolant leak? Where are the other 2 hoses for heater

My wagon has dual heat zones, one for driver and one for passenger, hence the extra hoses. If yours is just one heat zone it will just have 2 hoses. If the coolant is leaking inside the passenger compartment that is the heater core leaking. If you want to bypass it, I would try to find a piece of pipe and clamps between the shortened hoses or for a better fix with less joints, a hose to go between the outlet on the block that is supposed to go to the core, and connect from the out on the block back to the return near the same point, thereby bypassing the heater core. Let me know if you have any questions

 

[Mimmi]

There is only 1 heater core and it has 100% coolant flow all time. Dual zones are equipped with temp flaps.
Heater bypass valve bypasses heater core coolant flow when you select LO on ACC.

 

[Mariosaab]

I have 2 zones but think there is only 2 pipes going into the firewall. I bypassed by joining those popes before entering the firewall. Good choice? I don’t know. But I still get fogged up windows on passenger side though a coolant leak steaming from behind driver firewall has stopped. Could there still be coolant leaking behind firewall from some hose on passenger side still entering there?

2003 9-3 arc cabrio

 

[Mike Brennan]

There is a lot more than just bypassing the HCV. Look up McKay hose and installation instructions to get an idea.

 

[Mimmi]

Have you cleaned and dried all mats etc?

 

[unclemiltie]

Well, let's see. This is from memory but I did just put my engine back in the car

Coolant:

• A U-shaped hose that goes on the water pump
• A large hose that goes from the water pump to the radiator
• A large hose that goes from the top of the radiator to the cylinder head
• a small hose that goes from the top of the radiator to the coolant reservoir
• A larger hose that goes from the bottom of the coolant reservoir to a pipe that feeds into the back of the water pump
• A hose that comes from the heater core to a pipe on the back of the engine, this has a "Y" in it that goes to the heater bypass valve as well for when the heater is "bypassed"
• A hose that goes from the side of the engine to the heater bypass valve
• A hose that goes from the bypass valve to the heater core
• two hoses that are used to heat the throttle body so that it does not ice up.

Vacuum (this from a pre-2004 with the old updated PCV)

• A hose from the turbo boost release valve to the boost controller valve on the firewall (center tap)
• a hose from below the two coolant lines to the TB to the boost controller valve (left tap)
• a hose from the throttle body to the left of the coolant lines that goes through a check valve to the PCV nipple on the valve cover
• a hose that goes from the nipple on the intake manifold to the fuel pressure regulator
• a hose that goes from that same nipple through a T to both the heater bypass valve and the boost controller valve (right tap)

EVAP/boost control

• a hose that comes out of the back of the throttle body into the EVAP system
• a hose that comes from a T on the valve on the COBRA pipe into the EVAP system
• the three hoses from the same valve on the COBRA pipe that goes to the waste gate actuator, the COBRA and to the turbo compressor housing.
• And then there are some hoses that go to the charcoal canister under the right front fender and run to the gas tank.

I think that I got them all. My car doesn't have the heater bypass valve anymore so I've eliminated a couple of vacuum lines as well as the Y-coolant line. So those are from memory.

 

[redaero-wagon-2000]

There is only 1 heater core and it has 100% coolant flow all time. Dual zones are equipped with temp flaps.
Heater bypass valve bypasses heater core coolant flow when you select LO on ACC.

Mimmi you got it right. There is so much misunderstanding on the by pass valve and all that dumb plumbin.. Dual heater cores is a new bit of mis information. I have been running with no by-bypass valve in a very warn climate for many years and it is all just fine. No one ever uses LO on the A/C.

 

[Mariosaab]

Have you cleaned and dried all mats etc?

No net yet ... I suppose I should and if there is water behind firewall I should leak out via some drain correct?

 

[Mimmi]

Should,if drains are clean.

 

[Cap'n P.Zazz]

Well, let's see. This is from memory but I did just put my engine back in the car

Coolant:

• A U-shaped hose that goes on the water pump
• A large hose that goes from the water pump to the radiator
• A large hose that goes from the top of the radiator to the cylinder head
• a small hose that goes from the top of the radiator to the coolant reservoir
• A larger hose that goes from the bottom of the coolant reservoir to a pipe that feeds into the back of the water pump
• A hose that comes from the heater core to a pipe on the back of the engine, this has a "Y" in it that goes to the heater bypass valve as well for when the heater is "bypassed"
• A hose that goes from the side of the engine to the heater bypass valve
• A hose that goes from the bypass valve to the heater core
• two hoses that are used to heat the throttle body so that it does not ice up.

Vacuum (this from a pre-2004 with the old updated PCV)

• A hose from the turbo boost release valve to the boost controller valve on the firewall (center tap)
• a hose from below the two coolant lines to the TB to the boost controller valve (left tap)
• a hose from the throttle body to the left of the coolant lines that goes through a check valve to the PCV nipple on the valve cover
• a hose that goes from the nipple on the intake manifold to the fuel pressure regulator
• a hose that goes from that same nipple through a T to both the heater bypass valve and the boost controller valve (right tap)

EVAP/boost control

• a hose that comes out of the back of the throttle body into the EVAP system
• a hose that comes from a T on the valve on the COBRA pipe into the EVAP system
• the three hoses from the same valve on the COBRA pipe that goes to the waste gate actuator, the COBRA and to the turbo compressor housing.
• And then there are some hoses that go to the charcoal canister under the right front fender and run to the gas tank.

I think that I got them all. My car doesn't have the heater bypass valve anymore so I've eliminated a couple of vacuum lines as well as the Y-coolant line. So those are from memory.

Holy Sh**, THANK YOU this should be pinned somewhere accessible for everyone to Access