2014 Mitsubishi Outlander GX 4HS PHEV Heater Problem with a twist.

[Eugene]

Hello again; I have read and watched a few YouTube videos on this subject and used these to investigate my continuing problem of the heater not working. I can tell you it's not fun driving a car at 3 degrees. So this is what I have checked and found out:

• I have checked the inline filter on the hot feed pipe to the heater matrix. Despite my car from 2014, it was clean, with very few foreign objects in the filter.
• I have also striped the four-way valve and found again no foreign particles.
• The hot water feed pipe to the heater matrix is hot. Despite this, I back-flushed the matrix with no effect.
• I have tried the various climate controls and settings, and no effects.

I am puzzled about what stops the hot water from flowing through the heater matrix.

Any suggestions?

 

[NightPHEVer]

Hello again; I have read and watched a few YouTube videos on this subject and used these to investigate my continuing problem of the heater not working. I can tell you it's not fun driving a car at 3 degrees. So this is what I have checked and found out:

• I have checked the inline filter on the hot feed pipe to the heater matrix. Despite my car from 2014, it was clean, with very few foreign objects in the filter.
• I have also striped the four-way valve and found again no foreign particles.
• The hot water feed pipe to the heater matrix is hot. Despite this, I back-flushed the matrix with no effect.
• I have tried the various climate controls and settings, and no effects.

I am puzzled about what stops the hot water from flowing through the heater matrix.

Any suggestions?

See 'Heater Question' on 'General Mitsubishi Outlander PHEV forum' re. my experience of getting the heater to work again. Likely to need the citric acid treatment and mysterious knowledge of how to bleed the system once it is clear.

 

[Eugene]

Thanks, NightPHEVer, I will take a look.

 

[nrayanov]

To diagnose and fix your heating issue, you need to carry out some steps:

1. There could be stuck airflaps. To reset/fix this, you need to put the car into ACC2 mode, push AUTO on the HVAC controls, and then press the MODE button 20 times, pausing for about 5 seconds between each press.

2. If this doesn't help, the cabin temperature sensor might be blocked with fluff/dust, and/or other stuff. It's located behind the gashes on the dashboard near the steering column. You can clean that with a compressed air can.

3. The cabin heater matrix might be blocked. You can check on YouTube to learn how to fix this or find a garage to do it for you.

4. The 4-way valve might be blocked. You can check on YouTube to learn how to fix this or find a garage to do it for you.

5. If none of the above fixes the issue with heating, you are probably looking at a broken electric heater or electric pump, especially if it heats fine from the engine.

 

[Eugene]

See 'Heater Question' on 'General Mitsubishi Outlander PHEV forum' re. my experience of getting the heater to work again. Likely to need the citric acid treatment and mysterious knowledge of how to bleed the system once it is clear.

 

[Eugene]

I managed to sort this issue out. It was a blocked heater matrix, and the fix was to flush out the system and replace the coolant. Thanks for helping out.

 

[Farmer]

I've just had my (very low mileage) 2021 Outlander in for a warranty fix - no heating except when on a motorway in Save where I got a little bit coming through. When I phoned the garage, the first thing the lady said when I mentioned "Outlander" was "you need your heater fixing?"! She says that every year at about this time, all the Outlander owners come in to get their heaters fixed.

This is not good.

The garage was great and fixed it under warranty, and has given me the details of their work which I'll share in case it helps anyone:

"Investigation into heaters not getting warm. Found electric pump not working.
Carried out pump test - requires new pump. Found electric heater and matrix blocked, requires system flush as per technical bulletin.
Carried out coolant system flush.
Replaced electric coolant pump, tested all OK.
Rechecked from cold, tested, all OK."

I have a question; the system flush. Does the coolant have any inhibitor in it? Or is this like a central heating system; we're going to keep getting a build up of crud from the system?

Does anyone do any preventative work to stop this happening?

Not impressed with Mitsubishi on this. Touchscreen and heater issue in a virtually brand new (mileage wise) car. Are there any other common faults to look out for?

 

[littlescrote]

I've just had my (very low mileage) 2021 Outlander in for a warranty fix - no heating except when on a motorway in Save where I got a little bit coming through. When I phoned the garage, the first thing the lady said when I mentioned "Outlander" was "you need your heater fixing?"! She says that every year at about this time, all the Outlander owners come in to get their heaters fixed.

This is not good.

The garage was great and fixed it under warranty, and has given me the details of their work which I'll share in case it helps anyone:

"Investigation into heaters not getting warm. Found electric pump not working.
Carried out pump test - requires new pump. Found electric heater and matrix blocked, requires system flush as per technical bulletin.
Carried out coolant system flush.
Replaced electric coolant pump, tested all OK.
Rechecked from cold, tested, all OK."

I have a question; the system flush. Does the coolant have any inhibitor in it? Or is this like a central heating system; we're going to keep getting a build up of crud from the system?

Does anyone do any preventative work to stop this happening?

Not impressed with Mitsubishi on this. Touchscreen and heater issue in a virtually brand new (mileage wise) car. Are there any other common faults to look out for?

A central heating system should not keep getting a build up of crud of dosed correctly, although open vented systems are much worse than sealed unvented systems due to the continuous oxygen entrainment that feeds the process.

An automotive cooling system is similarly sealed and similarly dosed with inhibitors in the coolant (antifreeze, which is not only a frost protection, but also corrosion inhibitor, although I don't think automotive glycol has biocide in).

The blockages are not normal for vehicles, but occur on this particular one due to the leftover engine block casting debris. The very fact that a service bulletin exists tells you that it's systemic.