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-   -   02 Montero XLS Heat Issue Making Techs Scratch Their Heads (https://mitsubishiforum.com/forum/mitsubishi-montero-montero-sport-14/02-montero-xls-heat-issue-making-techs-scratch-their-heads-37483/)

john196899 10-28-2010 03:01 PM

02 Montero XLS Heat Issue Making Techs Scratch Their Heads
 
As the title indicates I have been unable to get any consistant information in regards a diagnosis. My 02 Montero XLS, with 145K miles has heat blowing from the driver's left side dash vent, and as you move closer to the passenger side, the heat is cooler and completely cold on the passenger right side dash vent. The same applies for the floor heat. I have gotten everything from a door might be open, to heater core. Has anyone out there experienced anything like this, and what was the remedy???? I don't want to get roped into replacing something I don't need to

redturboeclipse 10-28-2010 06:52 PM

which techs? mitsubishi dealer?

john196899 10-29-2010 12:48 PM

Dealer says it might be a heater core, and two other mechanics I have taken it to say it's not the core, it is something else. Their reasoning is that if the core was bad there would be no heat at all.

mxmikie 10-30-2010 10:15 PM

its the blend motor very comon

john196899 11-08-2010 03:15 PM

Thanks
 

Originally Posted by mxmikie (Post 265266)
its the blend motor very comon

Thanks for the info Mike, I really appreciate the assistance.

kimzz69 02-18-2014 10:29 PM

did it work John 196899
 

Originally Posted by john196899 (Post 265534)
Thanks for the info Mike, I really appreciate the assistance.





was it the blend door? im having the same issue.

kimzz69 02-18-2014 10:31 PM

or blend motor?

elixirbooks 08-30-2015 04:08 PM

Heater Remedy !
 

Originally Posted by john196899 (Post 265192)
As the title indicates I have been unable to get any consistant information in regards a diagnosis. My 02 Montero XLS, with 145K miles has heat blowing from the driver's left side dash vent, and as you move closer to the passenger side, the heat is cooler and completely cold on the passenger right side dash vent. The same applies for the floor heat. I have gotten everything from a door might be open, to heater core. Has anyone out there experienced anything like this, and what was the remedy???? I don't want to get roped into replacing something I don't need to

Same problem in 2001 Montero Limited. Little heat from driver vent but none on passenger. Turn on fan to max

elixirbooks 08-30-2015 04:12 PM

Heater Remedy !
 

Originally Posted by john196899 (Post 265192)
As the title indicates I have been unable to get any consistant information in regards a diagnosis. My 02 Montero XLS, with 145K miles has heat blowing from the driver's left side dash vent, and as you move closer to the passenger side, the heat is cooler and completely cold on the passenger right side dash vent. The same applies for the floor heat. I have gotten everything from a door might be open, to heater core. Has anyone out there experienced anything like this, and what was the remedy???? I don't want to get roped into replacing something I don't need to

Turn on fan to the max. I used meat thermometer inserted in vent. Cycle between AC and heat 115xs and voila, heat started coming out of passenger side. Blend door had gotten stuck. 100° now. Best wishes.

matt1992 11-29-2017 11:39 PM

Was the blend door the confirmed fix? Did you have to replace the entire heater box or was the door replacable? Finding a good in depth parts diagram for this thing is next to impossible. My Montero should be similar, its a 2006 limited. Driver side swtiches from hot to cold and passenger side stays cold. Im pretty sure I seen the blend air door actuator move so I suspect a broken door in the air box.

jstecz 01-09-2018 11:42 AM

I'm fighting this problem now... I think the blend door/actuator is behind the glove compartment, I'm going to see if I have movement there and then move to flushing the heater core.

Are there any good troubleshooting guides or diagrams for this?

jstecz 01-18-2018 09:12 AM

I solved my problem, but not necessarily in the best way.

I pulled the heater hoses and blew out the heater core with water and then compressed air, it seemed very clear, hooked things back up and burped and burped the system and no luck. Same problem, occasionally I would get warm air out of the far left vent.

Then I checked the rear heater, no hot air their either. At that point I decided to eliminate the rear heater from the bundle of snakes next to the transmission. After getting rid of the tees in the line to go to the rear heater I now have heat. after disconnecting the rear heater, I blew out the lines to the rear heater core and it did not have new coolant in it, so there wasn't good flow back there.

I still think this was stull a burping issue, but but getting rid of the tees and forcing all water through the front core, I managed to get the bubble out. I wonder if I reconnected the rear heat, but put the 2 cores in series if it would help. But I don't really need rear heat.

The heat and defrost worked well on a sub freezing day, so I'm calling it fixed.

alsaaron 11-12-2018 08:35 AM

I am curious if your problem is still fixed, as I have the same issue on my 2003 Montero limited and, as you said, mechanics are scratching their heads. The mechanic I took it to also suggested cutting off the rear heat lines/heater core to simplify the system. He also cleaned out the lines in the front. The heat did improve, but it is nowhere close to where it should be. Can you provide any additional information as to what you did? Did you replace the coolant lines? I am just not sure I understand what you did. Many thanks!

Clytnjms 11-22-2018 11:05 PM


Originally Posted by alsaaron (Post 325408)
I am curious if your problem is still fixed, as I have the same issue on my 2003 Montero limited and, as you said, mechanics are scratching their heads. The mechanic I took it to also suggested cutting off the rear heat lines/heater core to simplify the system. He also cleaned out the lines in the front. The heat did improve, but it is nowhere close to where it should be. Can you provide any additional information as to what you did? Did you replace the coolant lines? I am just not sure I understand what you did. Many thanks!

My heater wasn't working good but I had used some of that barqs radiator stop leak until i installed a new one, which worked very well as far as stopping the leak. After i installed the new radiator, I wasn't getting any heat so I ran the radiator without the cap on for about 15 minutes or so. I also realized the upper radiator hose needed replaced. So those two simple things completely solved my issue. I have super hot heat now. I originally thought that stop leak plugged up my heater core but that wasn't the case at all.

Larry McDowel 01-22-2019 04:35 PM

Having exact same issues, What is this blend door? how do I confirm if it is the culprit? I was originally thinking it is not burping, and have been trying several different ways to burb, still cold on passenger side.

HunterD 01-22-2019 08:41 PM

Blend doors is the little gates inside the climate control system that direct air one way or the other. It is possible for them to get stuck. Do you get actual airflow from cold vents, or just no air coming at all?

Larry McDowel 01-23-2019 04:13 AM

Air flow not the problem, lots of air flow. Problem is trying to heat the cabin up. air is hot from the left side, and get colder as you go across the dash/vents to the right side. Might still need to burp the cooling system again, (for the 5th time).
I'd think the blend door would allow even temperature across all vents no matter what position it was stuck. if it was stuck in the cold...cold air from all vents. Stuck in the warm position.... warm air from all vents. Stuck in the hot position,,,, hot air from all vents. I am not gettting this, but hot on one side, and gradually colder as I go across the vent to the right.

Valdo Armuand 02-05-2021 11:27 AM


Originally Posted by Larry McDowel (Post 325919)
Air flow not the problem, lots of air flow. Problem is trying to heat the cabin up. air is hot from the left side, and get colder as you go across the dash/vents to the right side. Might still need to burp the cooling system again, (for the 5th time).
I'd think the blend door would allow even temperature across all vents no matter what position it was stuck. if it was stuck in the cold...cold air from all vents. Stuck in the warm position.... warm air from all vents. Stuck in the hot position,,,, hot air from all vents. I am not gettting this, but hot on one side, and gradually colder as I go across the vent to the right.




So has anyone fixed that issue? I have been flushing the coolant system, flushed heater core, cleaned inside temp sensor, changed thermostat. No changes at all.

Naeos_Valkarian 02-05-2021 02:49 PM


Originally Posted by Valdo Armuand (Post 332202)
So has anyone fixed that issue? I have been flushing the coolant system, flushed heater core, cleaned inside temp sensor, changed thermostat. No changes at all.

I'm assuming you're having the uneven distribution of heat issue like you quoted. The problem is likely air trapped in the radiator or possibly the dash wasn't reassembled correctly leading to air escaping the ventilation ducts in places it shouldn't. To eliminate possible air bubbles, get yourself something like a no spill funnel kit that can connect to the radiator fill port and put some antifreeze in it (about 1/4th full), jack up the front end so the radiator fill port is easily the highest point in the system, start the engine and let it get up to operating temperature, turn on the heat to full blast and Start "bleeding" the system of air by gently increasing the rpm of the engine up and down a thousand or so rpms. This can be done in the drivers seat or by manually moving the throttle assembly(wear gloves, it can get uncomfortably hot). Watch as bubbles start burping their way out of the system and keep an eye on the fluid level in the funnel as you may need to top it off at points. Once you stop frequently seeing bubbles coming out, begin increasing the rpm of the engine. I find the best results at this point come from quickly bringing rpms up to 4500 or so and dropping it over and over. Once you do this a few times, switch back to the gentle method. At this point the air coming out of the vents should be significantly hotter than before.

Perform this until you are sure the system is bled correctly. If the issue persists after all this, look into taking the dash apart and reassembling correctly. There is a particularly pesky piece that sits directly atop the heater box that can get all cock-eyed when installing the dash if you're not vigilant.

Edit:
The insulation around the connecting points of the ventilation system and blend door can start falling apart with age, which can contribute to the uneven distribution issue. You can replace this material with padded weather stripping or a similar material, I'll leave it up to you what to use as there are many solutions to this.

HunterD 02-05-2021 04:19 PM

I have to say - I never in my life had an issue with bleeding air form my Montero cooling system. Not when replacing fluid, not when I replaced various hoses (including hoses to the cabin heater core), not even when I pulled and rebuild the engine. Not once in all these times did I have an issue with bleeding air out of the system.

Naeos_Valkarian 02-05-2021 05:08 PM


Originally Posted by HunterD (Post 332204)
I have to say - I never in my life had an issue with bleeding air form my Montero cooling system. Not when replacing fluid, not when I replaced various hoses (including hoses to the cabin heater core), not even when I pulled and rebuild the engine. Not once in all these times did I have an issue with bleeding air out of the system.

I will agree that 90% of the time I don't have issues either, only one time did I have to jack up the front end and do this and I burped my system for almost an hour before I saw that it was finally done.

HunterD 02-05-2021 06:47 PM

One thing that may help prevent air grtting trapped in heater core, is to make sure your temperature control is set all the way on HOT before you do anything.

Naeos_Valkarian 02-05-2021 06:59 PM


Originally Posted by HunterD (Post 332206)
One thing that may help prevent air grtting trapped in heater core, is to make sure your temperature control is set all the way on HOT before you do anything.

Unfortunately this does nothing to help on Montero Sports due to the neglect of the engineers in charge of designing the HVAC system. There is no heater core valve to control the flow of coolant to/from the core, the flow is constant. This actually plays a role into why so many people complain about poor AC performance on these trucks. I noticed a huge increase in cooling performance when I bypassed my heater core when it blew. Now this isn't to say having it on full blast doesn't have any merit, it does help to monitor the performance of the heater as you burp the system.

Edit:
I'm actually in the process of picking up supplies to make my own heater valve system. Using an old EGR control solenoid from another monty and a vacuum controlled heater core valve from Oreilly's. I'm awaiting my relays and electrical supplies from amazon and some free time to install it. I plan on making use of the unused vac port on the top right corner of the plenum to connect to the solenoid.

HunterD 02-05-2021 08:39 PM

Thank you for reminding that Sport is often an entirely different animal from full size Montero. Not all experience with one style translates directly to the other.

As far as making your own HVAC controller - have you considered using an electrically actuated ball valve? They make them in 12v version and I'd think it might be easier to control it with power supply than with vacuum. Just a thought.

Naeos_Valkarian 02-05-2021 11:07 PM


Originally Posted by HunterD (Post 332208)
Thank you for reminding that Sport is often an entirely different animal from full size Montero. Not all experience with one style translates directly to the other.

As far as making your own HVAC controller - have you considered using an electrically actuated ball valve? They make them in 12v version and I'd think it might be easier to control it with power supply than with vacuum. Just a thought.

When/If the solenoid fails I'll consider switching over to this, but unfortunately I already have purchased everything. I'll let y'all know how it turns out.


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