Heater Core replacement

freewayross

Adventurer
Hello, I have Gen 2.5 Montero. I see white smokes coming out of my went and the windshield gets foggy everytime I drive also the coolant level drops. I think it's a clear case of coolant leak inside the cabin, so heater core or the rubber parts around it? What has been your experience with these symptoms?

Also I called few local stores NAPA/Advanced no one has a part number for heater core, doesn't look like anyone sells it except OEM. The OEM part number I found is MN188337.

Does anyone have a link for a DIY? The closest I found was for Gen 2: https://www.youtube.com/watch?v=VyDP1QUncHg

Any help much appreciated, need to fix it before winter.

Thanks in advance.
 

freewayross

Adventurer
I've read that changing the heater core would mean a complete hvac system haul. As in recharge a/c put in compressor oil and stuff, that is how the montero system has been designed? Can some one help me out here if this is true and it's not as simple as swapping out the core?

Thanks
 

PacS14

Adventurer
I've read that changing the heater core would mean a complete hvac system haul. As in recharge a/c put in compressor oil and stuff, that is how the montero system has been designed? Can some one help me out here if this is true and it's not as simple as swapping out the core?

Thanks

I have not had to replace the heater core yet, but I can guarantee you that the heater core is separate from the A/C condenser and expansion valve. I replaced my ac compressor, and expansion valve and did not have to touch the heater core at all.

Now the only thing I can think that would make you have to remove them is if they were obstructing the heater core from coming out which I doubt. Download the manual for your vehicle or the closest year available and read before tackling the issue if you have doubts.
 

newworld2004

Adventurer
I am in same boat need heater core to be replaced, so for this to be fixed only Heather core needs to be replaced ? or there is other dependency.

Thx
 

Schitzangiggles

King of Macastan
Understand that the heater core and AC evaporator coil aren't hooked together per say, but they are often placed into the same HVAC ductwork and when I replaced the heater core I had to disconnect the AC hardlines where they passed through the firewall to be able to take the ductwork assembly out to the point where I could get to the heater core.

So I'd plan on having to recharge the AC system doing the heater core.
 

newworld2004

Adventurer
I am thinking to by-pass heater core for now as this is my second car. what size heater core by pass do it need? do I need 5/8 or 3/4?

Thx
 
Last edited:

TheMole

Adventurer
I listed the parts in the thread below when I used to have a Montero and I believe its 5/8.

 

cr4x4cruiser

Observer
A/C Interference; Yes, the A/C unit must be removed before one can remove the Heater Core... it is required, because there is not enough room to remove the Heater Core - unless the Heater Housing it sits in is moved towards the rear of the cabin [towards the dash].
While the complete job is very time-consuming, it is not extremely difficult. Further, most original - brass/ copper - Heater Cores can be repaired... often for under $100 [the same shop that does radiators do heater cores].
We have done two of these in the past two months... it gets easier every time.

A/C Disconnect; Consider finding a shop to retrieve/ empty the A/C system, rather than dumping refrigerant into the atmosphere. Likely, the shop will afford you a discount when it comes time to refresh/ fill the A/C system.

Notes:
Consider a heater core service as an excellent time to...
... run wiring through the firewall - for other projects.
... factory alarm removal.
... ignition cut-off switch install [theft deterrent].
... antennae replacement.
... stereo replacement.
... dash/ console light bulb replacement.
... usb/ voltage meter install.
... switch installs.

Plan ahead...
Have patience...
Have a second set of hands to remove/ re-install the actual dash...

Much success
 

newworld2004

Adventurer
I listed the parts in the thread below when I used to have a Montero and I believe its 5/8.

Thanks you Sir,
 

newworld2004

Adventurer
A/C Interference; Yes, the A/C unit must be removed before one can remove the Heater Core... it is required, because there is not enough room to remove the Heater Core - unless the Heater Housing it sits in is moved towards the rear of the cabin [towards the dash].
While the complete job is very time-consuming, it is not extremely difficult. Further, most original - brass/ copper - Heater Cores can be repaired... often for under $100 [the same shop that does radiators do heater cores].
We have done two of these in the past two months... it gets easier every time.

A/C Disconnect; Consider finding a shop to retrieve/ empty the A/C system, rather than dumping refrigerant into the atmosphere. Likely, the shop will afford you a discount when it comes time to refresh/ fill the A/C system.

Notes:
Consider a heater core service as an excellent time to...
... run wiring through the firewall - for other projects.
... factory alarm removal.
... ignition cut-off switch install [theft deterrent].
... antennae replacement.
... stereo replacement.
... dash/ console light bulb replacement.
... usb/ voltage meter install.
... switch installs.

Plan ahead...
Have patience...
Have a second set of hands to remove/ re-install the actual dash...

Much success
Great Info. Thanks,
 

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