[vigsom]

The Mitsubishi Pajero Sport comes with an auxiliary fan that cuts in when the AC Compressor kicks in.

This fan augments the function of the main clutch driven fan.

The issue

This fan would rotate slow at times, and, if the body of the fan was tapped with a tool, the speed would normalize - something similar to what one would experience in some non AC coaches in some trains.

This wasn't impeding the performance of the cooling system OR AC, but a fan has to work as intended.

The fan motor wasn't easily available, and given its slim construction was pricey - a good enough opportunity to try and service the existing motor.

Here goes :

1. Disassemble the fan assembly


2. The motor casing is glued - pry open the casing at the three holes using a strong but sharp screwdriver


3. Carefully open the casing by pulling it apart.


4. I found the motor full of carbon - it's been slogging for 8 years so has to be so.





5. Separate the armature from the stator(magnet) - note the unique design of this armature

6. Clean the carbon out using a soft cloth , then polish the commutator - I used 2000 grade emery for the fine finish.

7. Use a thin blade to remove carbon build up between the various segments of the commutator

7. The carbon brushes were found to be good enough and so I let them be.

It is surprising to see the brushes in such good shape even after 8 years. I observed the brushes to have a residual life of 2 more years or even more.



8. Apply a thin layer of glue around the circumferential joint of the two casings, so that the top and bottom casings stick after step9 is executed.

9. Re - assemble the motor - be careful to place those two plastic washers back in the center bottom of the bottom casing and the center top of the top casing- the rotor bearings rest on these.

10. Re - assemble the fan



The fan works like a charm now.

[lapis_lazuli]

Lovely restoration. I was wondering, what glue you used, and perhaps, the original glue was also meant to resist water ingress, spread uniformly along the circumference. After 8 years, the innards look shiny, except the carbon deposit ! What make was the motor?
OTOH, I was actually expecting the fan to be BLDC... Usually Japs adopt the new technologies faster.

[vigsom]

Originally Posted by lapis_lazuli

the original glue was also meant to resist water ingress,What make was the motor?

The motor had a weird looking M on it bearing a part number 37406J520.

The Mitsubishi part number for the motor is 7812A100; the complete fan assembly is supplied by Valeo.

I used a layer of fevibond. Silicone sealant would also work but I felt it might be an overkill. I didn't want excess adhesive/sealant to get inside.

The top and bottom casings when fitted seal perfect since there is a magnet as the stator inside.

Also, the motor is on the inside - towards the AC condenser and well protected.

[Ravi Parwan]

Awesome DIY. I have had a number of fan failures in my Indica, but as the prices were lower for the spares and I never had the courage to open up the sealed unit and rely on a resealed unit, never got around to doing this.

But does the motor suffer just due to carbon dust from the brushes? just a simple cleaning allows the motor to run properly?

Also did the shaft run free before cleaning? did you lubricate the bearings? sorry for asking all these questions, but am facing issues with my AC external fans and planning to open them up shortly.

[vigsom]

Originally Posted by Ravi Parwan

Does the motor suffer just due to carbon dust from the brushes?

just a simple cleaning allows the motor to run properly?

Also did the shaft run free before cleaning?

did you lubricate the bearings?

Any such motor, when serviced will mean

- Cleaning out all the carbon
- replacing the carbon brushes if required
- polishing the commutator, and ensuring that the cuts between various segments in the commutator are distinct and free of carbon

The shaft ran free before cleaning.

The miniature bearings are sealed, as you can see in some pics that I'd posted - they bear the number 607z and are made by NSK.

If replacement motors are available for, say, 1500 bucks, it would make better sense to go new.

A point on the carbon brushes - putting in any brush can damage the commutator over time. It is important to use the right grade(softness) of brushes meant for the motor. I haven't gotten to understand the grades of brushes as yet.

[Sandy Damodaran]

Originally Posted by vigsom

The Mitsubishi Pajero Sport comes with an auxiliary fan that cuts in when the AC Compressor kicks in.

This fan augments the function of the main clutch driven fan.

The issue

This fan would rotate slow at times, and, if the body of the fan was tapped with a tool, the speed would normalize - something similar to what one would experience in some non AC coaches in some trains.

This wasn't impeding the performance of the cooling system OR AC, but a fan has to work as intended.

Hi @vigsom, So I finally managed to get a Pre owned Pajero Sport, after a lot of convincing my family, given that I have a Cedia already, wasn't a easy job at all . Your Thread on getting one recently was super helpful.

I got the Car pretty cheap and have done the following till now
1) Clutch plates replaced (FNG)
2) Front suspension (Strut kit) + Tie Rods Replaced (ASS, yes they still exist , AYL in Pune)
3) Seats + Roof Liner changed to OEM quality ones
4) Tyres changed to Michelin ATX Trail Standard Size.

Now the problem is the AC blow volume is not great, and the AYL people said it is because of the Aux fan not spinning freely. I already got the vents cleaned etc.

As you might guess, the replacement cost is not cheap and the quote is for 30K. I was planning to do this as DIY and just wanted to know a couple of things.

1) Looking at this fan on my car, I thought I'd just need to remove the clips holding the grille and pull it out. And then remove the Fan.Does it have any specific locking mechanism holding it( The Grill)?

2) I also saw that you mentioned that this did not impact the AC efficiency, whereas the ASS guys are saying that is the Root Cause. Any opinion on this?

3) The OEM Brake pads are being quoted for 20K for the whole set, Just wanted to know if you are using the OEM ones or anything else.

4) There is apparently a Jounce rubber fitted on the rear suspensions as OEM which were missing in mine. These again cost a bomb (20K/Pair). Are they present in your vehicle?

[vigsom]

Originally Posted by Sandy Damodaran

AC blow volume is not great, and the AYL people said it is because of the Aux fan not spinning freely.
I also saw that you mentioned that this did not impact the AC efficiency, whereas the ASS guys are saying that is the Root Cause

I feel that the problem that you are facing (AC blow volume) is because of
a) a clogged evaporator OR Cooling Coil as it is commonly called or
b) a weak blower

The aux fan, as the name suggests is auxiliary. The main clutch driven fan, in my view, is more than enough to take the heat load of the radiator and the AC condenser, and the Aux fan, which is a pusher fan, just pushes that additional air for improving heat transfer in the condenser. This additional air is anyways pulled by the main fan. Please check the old Innova and the 2009-2016 Fortuner for reference. They run on the main clutch fan alone.

If your evaporator is clogged, it is only because the Pajero Sport doesn't come with a cabin air filter by default, which even I discovered as a shock. I installed one per this thread (A/C Air Path clean out + Cabin Air Filter installation - Mitsubishi Pajero Sport)

My saga with the Pajero Sport AC was rather long and painstaking as can be seen in the following threads

1. diagnosing leaks (Mitsubishi Pajero Sport | Diagnosing an Ultra-Low Leak in the Aircon System)

2. Rectification of errors (Car Air-Conditioner Service | The cost of poor quality)

On the brake pads, my car's brake pads have adequate thickness and bite. I need to check on the rear suspension rubber but didn't find any abnormality when I inspected it last. Mitsubishi OE spares are pricey, and one can't be sure of their "OE-ness" even after paying the money.

[Sandy Damodaran]

Originally Posted by vigsom

I feel that the problem that you are facing (AC blow volume) is because of
a) a clogged evaporator OR Cooling Coil as it is commonly called or
b) a weak blower

Seems like both were the cases with my PS.
Basis your other article, I opened up the Aux fan and fit it back, but that did not seem to have any improvement on the throw.
Long back I had taken my Cedia to FNG AC mechanic near my home. Caught hold of him and explained the issues.

The evaporator was fully clogged. and so were the pipes.

Originally Posted by vigsom

The aux fan, as the name suggests is auxiliary. The main clutch driven fan, in my view, is more than enough to take the heat load of the radiator and the AC condenser, and the Aux fan, which is a pusher fan, just pushes that additional air for improving heat transfer in the condenser. This additional air is anyways pulled by the main fan. Please check the old Innova and the 2009-2016 Fortuner for reference. They run on the main clutch fan alone.

If your evaporator is clogged, it is only because the Pajero Sport doesn't come with a cabin air filter by default, which even I discovered as a shock. I installed one per this thread (A/C Air Path clean out + Cabin Air Filter installation - Mitsubishi Pajero Sport)

I Did chance upon this thread as well, would be getting a cabin filter installed now.

Originally Posted by vigsom

My saga with the Pajero Sport AC was rather long and painstaking as can be seen in the following threads

1. diagnosing leaks (Mitsubishi Pajero Sport | Diagnosing an Ultra-Low Leak in the Aircon System)

2. Rectification of errors (Car Air-Conditioner Service | The cost of poor quality)

On the brake pads, my car's brake pads have adequate thickness and bite. I need to check on the rear suspension rubber but didn't find any abnormality when I inspected it last. Mitsubishi OE spares are pricey, and one can't be sure of their "OE-ness" even after paying the money.

Once I get these cleaned and refitted I would be keeping an eye out for leakages, hopefully I get lucky

On the rear suspension, I got lucky and there is a ASS in Pune (AYL, who are basically staffed with older Pethkar staff), They had the Front Strut Kit and Tie Rod ends which were shot.

The OEM Brake pads cost ~20K for all four, I'm planning to get a Brembo ones for the same cost. I'm unable to name the pics asto what stages they are in.

Finally, Thanks a ton Vigsom, your posts and you have been super helpful and fantastic.