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-   -   Advice on fitting an air-conditioner in the Mahindra Thar (https://www.team-bhp.com/forum/4x4-technical/99916-advice-fitting-air-conditioner-mahindra-thar.html)

Dear all - AC INSTALLATION IN THAR CRDE. I am giving herewith, guideline / preliminary information for dealer equipped AC installation procedure for Thar CRDe.

Please give your comments. I am attaching one photograph.

Best regards,

Behram Dhabhar

SOP FOR AC FITMENT ON THAR CRDe
The Thar CRDe vehicle comes with a factory fitted Heater unit consisting of Blower, Heater Core and Air Distribution system. This vehicle can be equipped with an AC unit. A typical AC unit basically comprises of the following components. Compressor / Evaporator unit / Condenser unit / Expansion valve / Receiver Drier Bottle / Refrigerant Flow Lines / Electrical items like Relays, Controllers, Wiring etc / Refrigerant. In forthcoming sections the existing set up in the vehicle and the nature of change required on each component is elaborated in detail.

Compressor installation procedure - the engine is fitted with an idler pulley, driven by a 7 groove serpentine V-belt. The idler pulley must be replaced with the compressor, same as used in Bolero VLX.

Following steps need to be followed for replacing the idler pulley with the compressor: ->
Loosen the tension bolt, tensioned pulley nut, to relieve the tension and take the belt out from the pulley seat. Once the V-belt is loosened from the pulley, the idler pulley mounting bracket can be removed by loosening the four mounting bolts and replaced with the compressor. The compressor is mounted on to the engine with Hex head flanged bolts M8 x 1.25- 105 mm long, torque to 35 +- 3 Nm. Place the belt over the pulley grooves and tightens the Tensioned pulley. Stabilized tension must lie between 140-145 Hz. Check for proper tightening of all mountings before starting the engine. The compressor comes with the specified amount of Compressor oil. Compressor oil specification is 135 cc, SP10 PAG.

Evaporator installation procedure - the Thar contains a Heater unit which consists of a heater coil housed within the evaporator housing. There are two ways of adapting this unit for AC application.
The first way is to replace the heater coil with a cooling coil. Loosen the bolts (5 nos) holding the evaporator top cover to the bottom cover, also remove two self tapping screws holding the top cover assy. Remove the heating coil housed within the bottom cover and replace with a cooling coil. For routing the AC pipes from the evaporator bottom cover, two holes need to be punched on the plug provided on it (marked). The cooling coil containing the AC pipes can then be routed through the evaporator for final assembly. Replace the top cover back to its original position and tighten the 5 holding bolts. Plug the ducts present in Thar evaporator top cover to prevent air leakage in the circuit. After assembly, ensure proper matching of blower and evaporator face so as to avoid any air leakages.

The second way is a much simpler mix and match method. This involves an extra evaporator unit. Loosen the bolts (5 nos) holding the evaporator top cover to the bottom cover of the heater unit (removed from Thar) as well as the new cooling unit. Swap the top cover removed from the Thar heating unit with the bottom cover housing the new cooling unit. Here, 2 evaporator units are combined to create one cooling unit suitable for use in Thar. Tighten the 5 holding bolts to the original specification. During assembly it will be seen that the drain pipe in this case is oriented towards the left, reorient it towards the right without any kinks for proper functioning. After assembly, ensure proper matching of blower and evaporator face in order to avoid any air leakages. The pipes carrying hot fluid to the coolant must be plugged as the AC circuit no longer requires this. Insert plugs similar to the ones used in engines having “no heater” application (standard parts). These are easily available, and aids easy fitment. After plugging the pipes in the circuit, the tightness and sealing of the joint must be ensured. The joint can be tightened by a suitable size band clamp or a spring band. The joints must be effectively sealed. As the heater unit is now not functional; the circuit carrying hot coolant needs to be plugged tightly. This can be done either by plugging the heater pipes carrying hot fluid into the Heater coil or by plugging the hot water point emanating from the engine side. This is a very critical activity, failure to do this properly will cause coolant leakage which may even lead to overheating, resulting in engine seizure. After completion of this activity, the evaporator installation is complete.

Electrical system installation procedure - as the HVAC system is being changed to AC from Heater, the wiring, switch plate, along with the HVAC controls in the vehicle need to be adapted for the same. The relays must be installed on to the bracket provided in the vehicle (RHS body panel above driver foot well). With this the electrical installation is complete. Ensure designated fuse is in place for condenser fan.

Condenser installation procedure - the condenser has been specifically developed for use in Thar. The specifications mentioned herein have been arrived at after considering all possible conditions, static as well as dynamic. Hence, it is very important that the technician sticks to these guidelines during the installation. Remove the deflector assembly along with the intercooler, intercooler pipes from the vehicle. The condenser contains a dual fan arrangement. The condenser comes with brackets which provide mounting provisions with the deflector box assembly. The relative orientation and clearances of intercooler and condenser assembly is important to ensure requisite performance. On the RHS of the deflector side panel a slot needs to be provided for routing the condenser inlet and outlet pipes, the size of the slot must be in accordance to the grommet provided in the condenser assembly. Once this step is done, the condenser is ready for assembly with the deflector. Once the intercooler, condenser and deflector box are mated together the final assembly will be ready for placement on the vehicle. The length of intercooler hoses change. While assembling the hoses proper tightening of hose with the intercooler must be ensured. Similar hoses can be used on the RH as well as LH sides. Clearances between condenser, intercooler and radiator have been defined in the design. In-order to establish good reliability with the installation, the boundary dimensions must be maintained.

Receiver Drier Bottle Installation - RD bottle to be used for this application is same as Bolero VLX. The RD bottle can be mounted on to the RH fender inner panel. Use O rings while connecting the AC pipes at the compressor end. Use O rings of 5/8” / ½”. The AC pipes connecting the Evaporator unit are, pipe assembly evaporator end and pipe assembly compressor end. AC pipes connecting the Condenser end are new. During plumbing of AC pipes, proper tightening and sealing of all joints must be ensured to avoid refrigerant leaks.
Refrigerant Installation Procedure - this is a standard procedure, so does not need elaboration. The refrigerant to be used is R-134a. The oil for compressor is unique for R-134a. Never run the compressor without the refrigerant in the system as the lubrication relies on the refrigerant flow. Do not allow liquid refrigerant to touch metal and chrome surface as this will damage the surface finish. Never discharge a system or do welding / brazing operations when the engine is switched ON. Most parts used for the AC installation are common with Bolero model. Hence, all standard service procedures like Charging, Discharging, and Purging, Evacuation, Leak Tests, Evaporator Cleaning and performance of Bolero can be taken as a reference.

Hi Behram,

Thanks for the advice! I have copied your post from the Thar review thread, to a new thread as it will be easier for the many Thar owners to find. Better to have this important info here, rather than buried in the middle of a 100 page thread.

Sir Behram,
Thanks for the very informative thread on Thar, how similar is the procedure for XD3P on CJ340, Enlighten please.
Regards,

Am I correct in assuming that Heater and AC cannot co-exist in the Thar? Is it that it can be equipped either with AC OR Heater but not both? Please enlighten.

^^ Only Heater, Only AC, Heater + AC, No HVAC all are possible, just a matter of add / remove something.

Spike:)

If Heater + AC is possible, why is there no option listed in the original post giving instructions?

The above post is only a brief. The original SOP for AC installation prepared by me is a 22 page document which will obviously not be disclosed here :). Those who need a Heater + AC can use Evaporator assembly from Bolero VLX. I have mentioned in my earlier post also- it will be AC only as of now (KISS principle).

Spike

PS- Primary requirement is "Thanda hava"

Dear Shankar Balan - hello after a very long time. Its nice to interact with you again. Whenever I enjoy the turbo whine with boost in the Thar CRDe as the speed climbs very quickly from 100 to 140 kmph, I think of you and your Scorpio (a grey DX if I am not mistaken).

Answer to query - WHY ONLY AC? - ref your query above, there is nothing in this world which cannot be done on one vehicle. My decision is to go in for AC alone is from production / cost effectiveness / simplicity points of view. India is either hot or hotter. I have never used the heater in my Scorpio / Bolero VLX in the last four years. Still if someone wants to fit it, say up north for example, one can always do it for one vehicle because finally the complete assembly is from Bolero only which has HVAC in its VLX and SLX configurations. I don't think it would be correct to load each and every vehicle with this additional system, that's all. I will still get replies saying that I am being unreasonable, I am not "in sync" with the market, I don't know how cold it becomes up north etc. I am prepared to recieve such replies and I understand and appreciate the feelings behind them. I hope people understand that you don't have to necessarily pay for something that most of you shall never use. This statement is correct. I have got a database on the number of Boleros where heater has never been used (my VLX MH15CM6341 included). I hope my answer conveys its logic.

By the way, in the last financial year, we made 83,127 Boleros. It is the largest selling MUV in India. Along with Thar CRDe, it is also my favourite vehicle.

Best regards,

Behram Dhabhar

@DB/Spike.

Does the AC install require integration into the ECU? For shutting off compressor at load, etc...

@BD Sir / Spike: What is the cooling efficiency with the soft top? What is the variance on mileage with a HT vehicle?

Cheers

Tension is measured using Hz? how? I've usually seen x mm displacement for y load. Most contemporary engines use serpentine belts with hydraulic tensioners anyway.
Doesn't the compressor clutch need to be wired to the battery? and of course the switch on the dash. Is the Thar prewired? How do you get 12v to the clutch?

I remember reading up on this a few years ago. Many a times tension is expressed as the frequency (in Hz) at which a section of belt will vibrate at when plucked like a guitar string. The more tension a belt has, the higher the frequency. Hence here the belt will vibrate anywhere between 140-145 times in a second at the correct setting.However, note that this specification will changes with temperature. Apparently this method is more accurate and has excellent repeatability. Hence as long as the measuring device has a reasonably accurate clock and is able to count every oscillation, it will remain accurate and periodic calibration is not required. This dead accuracy is required in many critical sections like the timing belt of top-end / sports cars. :thumbs up

Regards,
Adheesh Parelkar

Attaching a sketch of how this is done, would make things more clear.



You are absolutely right Adheesh:thumbs up

Spike

WHAT!!!???? No rain drop sensitive windshield that automatically turns the wipers on when it rains???

That does it for me, Mr. Behram. I'm going to start my own company and then you'll be sorry, sorry, sorry. You just wait.

Seriously, is the Bolero A/C unit the way to go or are the Scorpio...Pajero-Endeavor- A/C components better quality, besides being more expensive?

DB Sir / Spike,
I too need some help on this please. Any pointers from you will be really helpful.