Automotive Air Conditioning Information Forum (Archives)

BIG on Thu September 02, 2010 1:54 PM

Year: 99
Make: Mitsubishi
Model: Montero Sport
Engine Size: 3.0
Refrigerant Type: R134A

I will be replacing the A/C compressor and drier on my 99 Montero Sport due to a weak/noisy compressor and very poor cooling performance. I have several questions prior to starting this job.

1) I have a flush can I purchased from A/C kits.com. I've never used it and don't know how to exactly. Do I simply use a solvent such as mineral spirits in this can to flush my hoses, condenser and evaporator or should I put some chemical like R141B or Dura 2 in it? (I assume I fill it with mineral spirits and blow through these components until they are clean on the outlet side.) I

2) Is it ok to use shop air with this as long as I have a filter/drier in my shop air line or do you even use shop air in conjunction with this flushing can device?

3) I'm reading that I need to assure my expansion valve or orifice tube is clean of debris. Problem is, I'm not sure where it's located. I believe it's likely under the dash close to the evaporator since I don't see it under the hood. This looks like an absolute nightmare to take out. Is it necessary to check it or clean it? I was told it's simple to remove on this particular car (2 bolts) but I looked under my dash and I sure don't see it that way.

4) To flush my evaporator, can it be done leaving it under the dash and simply "blowing" through the fittings at the firewall with the hoses disconnected? I wonder about solvent or the cleaner "pooling" in the low spot of my evaporator such that pulling a vacuum prior to recharge won't get it all out and it ruining my system again. Is this feasible?

I just need some tips here folks. Thanks for any comments or questions to help you help me.

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It takes all kinds of people in this world, just less of some than others.

HECAT on Thu September 02, 2010 9:38 PM

1. In regards to your "flush can"; look on this page and tell me if you have the Pulsator kit or the Mastercool kit.

2. Dry Dry Dry shop air is Ok and regardless of which "flush can" you have, they both use air to operate.

3. It is either under the hood at the firewall where the lines connect or under the dash with the evap.

4. You can flush the evap. in place as long as the TXV is removed and you can blow high volume air to dry it out.

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bohica2xo on Thu September 02, 2010 11:34 PM

The TXV is inside the evaporator "suitcase".

The evaporator assembly comes out of the Sport without too much trouble. It is a bit more than two bolts, but it is not a Ford Focus either.

You should get a Mitchell subscription if you want all the pictures & steps. The lower dash cover (knee panel?) comes out, the bolt & lines in the engine bay come off, an electrical connector or two - THEN the two bolts will drop the suitcase from under the dash.

B.

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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

ACProf on Fri September 03, 2010 1:09 AM

Edited: Thu September 09, 2010 at 9:36 PM by ACProf

HECAT on Fri September 03, 2010 5:25 AM

Flushing chemical note: Mineral spirits will leave mineral oil residue and is not recommended (I would not use it) for use as an A/C flushing agent unless you plan to refill the system with mineral oil (i.e. R-12 system).

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BIG on Fri September 03, 2010 8:42 AM

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It takes all kinds of people in this world, just less of some than others.

BIG on Fri September 03, 2010 8:42 AM

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It takes all kinds of people in this world, just less of some than others.

iceman2555 on Fri September 03, 2010 8:55 AM

Never use mineral spirits or a mineral spirits based flush chemical in an automotive system. It is impossible to remove all traces without the use of other flush chemicals.
These are the result of a mineral based flush chemcial.



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The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson



Edited: Fri September 03, 2010 at 8:58 AM by iceman2555

BIG on Fri September 03, 2010 8:59 AM

Hecat, I have the mastercool type "flush can". I bought it from this site years ago and never ended up using it so I have no idea how it actually works. I'm a mechanical engr. by day and and have the aptitude to do this compressor/drier replacement correctly but I don't claim to have all the knowledge. That's why I'm here to learn all I can prior to ordering parts and starting the teardown.

The Montero Sport A/C has been very weak for months and finally about 2 days ago instead of just the annoying "rattling" we've become used to of the noisy worn compressor, my wife says it made a louder, different noise and she cut it off. I've had it on briefly since then and it still works (isn't locked up) but it's weak and needs replacement.

My idea to tackle this project:
1) Discharge system and remove compressor, drier, condenser, evaporator and hoses. This is given I find out removing the evaporator suitcase is not a 8 hour job.
2) Replace compressor, drier and thermal expansion valve (again given I can get the evaporator suitcase out from under the dash where this TXV is located).
3) Flush hoses, condenser and evaporator while out of the car and get them as dry as possible before reinstall (the compressor I will use has a simple filter/drier assembly on it's outlet line - is this enough to provide "dry dry dry air"?).
4) Replace parts to car, vacuum an hour or so and recharge.

Back to the flushing though, I'm totally stumped on how exactly to use my "flush can" correctly and what flush agent to use with it. It seems it would take a lot of whatever agent I use to flush all these parts correctly and at a hefty price/gallon I'm backing up questioning my alternatives. I want to do it right but I'm not a moneybag either. You say mineral spirits isn't encouraged due to the mineral oil residue it leaves? Give me detail on how to use this "flush can" and the gospel truth on my options as a flushing agent. I appreciate you help.

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It takes all kinds of people in this world, just less of some than others.

iceman2555 on Fri September 03, 2010 9:01 AM

This 'gunk' was throught out the system. Required a total system replacement. Could have possibly be flushed with a flush machine and the proper chemicals...however, the 'ole' blow thru method did not remove this material.





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The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson



Edited: Fri September 03, 2010 at 9:03 AM by iceman2555

BIG on Fri September 03, 2010 9:12 AM

Bohica2xo, I see the bolts at the firewall where the lines disconnect. I also see that if I removed my glove compartment I see the case the evaporator is in and the fan is just to the right of it. As viewed from the passenger seat, the fan is to the right, then the suitcase the evaporator is in is sandwiched in between the fan and the duct work. I assume if I am able to remove the fan and electrical connections and the cable that controls my recirc damper door, it will be apparent how the evaporator suitcase comes out?

I have the original Mitsubishi service manual for this vehicle on CD but it doesn't detail removing this evaporator as well as I would like. Are you telling me the online Mitchell manual will definitely be more detailed than what I already have?

Also, how in the world do I know whether I really need to remove my evaporator or not? I mean if it's not 100% certain that I need to replace my TXV valve do I really need to remove the evaporator at all? Or, is it necessary to flush my evaporator and the only way I can do get good airflow through my evaporator to flush it is remove the TXV valve from it? If that's the case the evaporator has to come out. I want to do it right without cutting corners but I don't want to waste my time on this detail if it's not something that's necessary.

Thanks for any comments or pointers. I want to know exactly how to proceed with confidence before starting this teardown and buying parts.

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It takes all kinds of people in this world, just less of some than others.

HECAT on Fri September 03, 2010 10:33 AM

OK, your "flush can" is basically a "you-fill" aerosol can, also known as the 1 qt. flush gun. Scroll down and read the post regarding "removing flush from evaporator".

You cannot flush through a TXV without highly specialized equipment.

With this particular "flush can" you have; you may have better luck flushing the evap removed from the vehicle, so you can reposition the component to let gravity assist in removing the waste oils. Personally, if I did not have specialized flush equipment and had to go hours into the dash to remove the txv and evap, I would just replace them.

As a matter of fact if there is any metal debris in the condenser, this tool will be so ineffective; the condenser must be replaced.

As a mechanical engineer also, I invite you to read the paper in my signature to gain a better understanding of the chemical and physical requirements for effective flushing.

No disrespct to the supplier or manufacturer, but I would put the little "flush can" away for another day when say you need to douche some solvent through a power steering line.

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bohica2xo on Fri September 03, 2010 10:49 AM

You simply can NOT flush through the TXV. It is located inside the suitcase, connected to the evaporator with two threaded lines. You can blame the engineer for this, it would have been much easier to service with a block type TXV at the firewall. In situ flushing would have been possible.

I can't say for certain that the Mitchell info is better than the OEM CD that you have - I have never seen the CD. Do you have an exploded diagram on the CD? Is there a step-by-step text instruction - "remove x, then remove y..." ? That is what is in Mitchell.

B.

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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

BIG on Fri September 03, 2010 1:48 PM

Thanks for all the help guys. I guess at this point I'm still up in the air about flushing the evaporator and replacing the TXV valve at all. I mean since I haven't had a compressor completely "lock up" (catastrophic failure) am I wasting my time worried about getting them out from under the dash and flushing them at all? Same goes for the condensor.

Even if I take them out and clean them with my "flush can" how do I know they are really clean and still don't have metal debris, etc. in them that will ruin my new compressor? I guess the easy answer is to replace every single part in the system but I sure would like to avoid that given I was planning on selling the vehicle soon anyway...

If I removed my drier and cut it open to see how much crud is in it, wouldn't this be a good indication of how much crud might have passed through to other components such as the condensor and evaporator/TXV? If I cut my drier open and see no excessive metal shavings etc. isn't this a good indication I could simply flush my condensor/hoses and not flush my evaporator or replace my TXV and move forward?

I don't believe in cutting corners but where in the world do I stop? Replacing every single component in a non-catastrophic failure of an A/C systems seems like I would likely be throwing new parts at a system that really didn't need them don't you think? All said and done, I'm selling this car within the next few months and it's only worth $4000 or so with the air working anyway.

Again, I truly appreciate all of your comments and suggestions.

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It takes all kinds of people in this world, just less of some than others.

ACProf on Fri September 03, 2010 2:18 PM

Edited: Thu September 09, 2010 at 9:36 PM by ACProf

HECAT on Fri September 03, 2010 3:24 PM

BIG, you have said the compressor is noisy and weak. I can only make the assumption that it is failing. Maybe it is not (been that way for a long time), maybe it is the clutch, maybe it is an idler, maybe its low on charge, maybe, maybe...

The condenser acts as the primary filter in modern 134a systems. The paths are .060" or less. After recovering the charge you can back blow or "pop" the condenser to look for signs of metal debris. This should give you the answer needed to formulate your "fix it to sell it" strategy.

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