AC for MM550 (and Jeeps in general)

akm225 · 8th April 2010, 16:28

Hi,
I recently bought a 2002 model MM540; the vehicle seemed to be in good condition until the AC was installed. Please read the below time line.

January 2010: Bought the vehicle (no AC), checked thoroughly by a mechanic and deemed to be in good condition. Temperature gauge constant at just below 80 deg mark, sometimes 85 - 90 deg in heavy traffic or when climbing a steep incline with 4X4 engaged.

February 2010: AC installed; everything seemed fine. After a couple of days though, started noticing the temperature needle dangerously close to the red mark. Switching off the AC makes the needle go back to just below 80 deg. However, after a couple of days, switching off the AC would result the needle to drop to 80 deg (not just below 80 deg mark). Noticed that radiator was losing water; obvious culprits were either loose hose connections or faulty radiator cap. Found out that radiator cap wasn’t original but couldn’t procure one; it seems that all spare part shops stock duplicate radiator caps worth just 25 bucks. Another strange thing noticed was that the temperature needle flicks back and forth between 80 deg and 100 deg when the clutch pedal is depressed and released. The obvious inference was that either the temperature gauge was faulty or there was some sort of a loose connection in its wires. Time was running short so decided to drive down the vehicle to Bangalore from Kerala without using the AC, and check with a good mechanic after reaching here.

AC details:

Sandem 507 condenser with Unicla blower (excellent cooling).

Condenser fitted in front of the radiator.

Electric fan fitted behind the condenser; the fan sucks in air through the condenser.

March 2010: Drove Vehicle to Bangalore, no problems encountered on the way. However, during the Ghats section (Nilambur – Gudalur), the engine temperature reached close to the red mark, but since the faulty temperature gauge problem still existed, while depressing the clutch pedal to change gear the temperature gauge needle flicked back to around 90 deg. Also, noticed that the exhaust was smoky so eased the accelerator pedal a little to reduce dumping unnecessary fuel into the cylinders, this bought down the temperature to 80 deg.
After a week, consulted a couple of mechanics here in Bangalore, all of them concurred that one problem could be the electric fan being installed behind the condenser. Their logic was that since the fan was sucking in air through the condenser, which is an obstruction, the fan’s effectiveness is questionable. And moreover, the hot air that the fan sucks in is then released towards the radiator, where it gets sucked through by the radiator fan. Now, by placing the fan in front of the condenser, the fan tries to push the air past the condenser; some of the air goes through the condenser while the remaining goes around it towards the radiator. Therefore the radiator will get cooler air in front of it.
Replaced radiator cap with original one; no lose of coolant after that.
Mechanic confirmed that there was a loose connection in the electric wire to the temperature gauge.

April 2010: Vehicle given to workshop with following instructions:

Install fan in front of the condenser.
Overhaul radiator.
Add a reservoir to the cooling system.
Fix temperature gauge.

I got back the jeep yesterday evening. During the drive back home, the temperature hovered between 85 and 95 deg (AC in full blast). The needle indicated 95 deg (maybe 90 deg, can’t differentiate) in bumper to bumper traffic. Once the traffic reduced and got a stretch of open road, the temperature started dropping to about 85 and stayed there (the temperature would eventually increase due to bumper to bumper traffic).

There seems to be obvious improvements, but is this enough, or is there more scope for improvement? If yes, what needs to be done.

I hope I have given enough information for all gurus out there to nail the problem. Hoping all of you guys reply.

Thanks

DesertKing · 13th April 2010, 13:09

Quote:

Originally Posted by akm225

Hi,
January 2010: Bought the vehicle (no AC), checked thoroughly by a mechanic and deemed to be in good condition. Temperature gauge constant at just below 80 deg mark, sometimes 85 - 90 deg in heavy traffic or when climbing a steep incline with 4X4 engaged.

Does your Jeep have a thermostate switch?? If yes, it will never let the temperature go down to 80 deg.

akm225 · 13th April 2010, 19:47

Hi DesertKing,

Thank you for replying.

No, my 540 doesn't have a thermostatic valve.

Thanks

Tejas@perioimpl · 14th May 2010, 16:14

I'm planning to do a couple of dashboard modifications to my classic and also have planned an AC install in the near future. The dashboard mod is basically extending the dash to have a center console extending all the way till the handbrake with a lockable compartment. I may relocate the handbrake to the right of the driver and free up more space (still considering this though).

Since i am planning the dashboard mod first, is it possible to just install a blower first and use it as a fan and do the AC install (compressor, etc) at a later date? This is important so that my dash can be sculpted around the blower.

Also, which blower is recommended?

Gypsy-Boy · 14th May 2010, 16:36

Superking - its one of the best blowers you can find!!
Am sure lotsa people here will say the same!!

Jaggu · 14th May 2010, 20:52

Superking or National, they have the best blowers. But i don't think it comes without the cooling coil assembly. Don't buy second hand stuff, buy a new one and wrap the coil inside with plastic so that dirt doesn't settle in till you complete the fitment of AC.

Key is finding the right size compressor, most often people install oversize compressor which are a drag on the engine and results in heating. For a classic put a 505 compressor with a plastic partition behind the front passenger area. Also remember to do good insulation at the firewall and the floor area. 507 might not really be required for such a small area.

Tejas@perioimpl · 15th May 2010, 10:56

Quote:

Originally Posted by Jaggu

Also remember to do good insulation at the firewall and the floor area.

This is the biggest issue. Insulation will take the brunt of water fording, monsoon leaks etc... Even after a day of slushing, one needs to jet clean the interiors as well and again this will completely rot the insulation. What to do about this?

Jaggu · 16th May 2010, 23:58

Have you seen the sound deadening and heat insulation patches on the floor of modern cars, just lift the carpet and check you will know what am talking about. Use it, you need to heat and stick it, lil expensive, but will take care of all your concern points.

sreerajunnithan · 18th May 2010, 17:53

Quote:

Originally Posted by Jaggu

Have you seen the sound deadening and heat insulation patches on the floor of modern cars, just lift the carpet and check you will know what am talking about. Use it, you need to heat and stick it, lil expensive, but will take care of all your concern points.

I recollect we discussed about this last weekend, any pointers on where we will get this?

--Sree--

Jaggu · 18th May 2010, 19:43

Should be available with any of the big spare stockist in the city. Its not a fast moving part so might have to order and wait for it. This is a universal product only the shape of the patch will defer from vehicle to vehicle. Trouble will be to identify the biggest piece available, this can be then ordered and then cut and pasted based on the requirement.

Also i have heard that 3M has the product, so a quick check with 3M dealers might help.

sreerajunnithan · 18th May 2010, 19:46

What's the technical name of this thingy?

--Sree--

Jaggu · 18th May 2010, 20:01

I have no idea of the name, it should be sound deadening pitch or something of that sorts. Its used for sound deadening and heat insulation on floor panels of the chassis.

SPIKE ARRESTOR · 18th May 2010, 20:57

Quote:

Originally Posted by sreerajunnithan

What's the technical name of this thingy?

Sreeraj, it is called as a "Melt sheet".

Quote:

Originally Posted by Jaggu

I have no idea of the name, it should be sound deadening pitch or something of that sorts. Its used for sound deadening and heat insulation on floor panels of the chassis.

Good one Jaggu LOL!, yes what you have mentioned is right, its main function is dampening noise and vibrations.

Spike

Jaggu · 18th May 2010, 21:27

aha and all this while you were just watching eh!! so how does it work for heat insulation?

SPIKE ARRESTOR · 18th May 2010, 21:42

Hehehe, as I told you earlier it is basically a sound deadening material the only protection it provides from heat is because, it acts as a layer between the heat conducting surfaces. You would find "melt sheets" mostly in the passenger compartments where better NVH levels are required. Moreover, heat sources are less under the passenger compartment. A component which prevents a majority of those heat radiations is the "firewall" which has a material with good heat resistance.

Spike

8th April 2010, 16:28	#46
akm225 Newbie Join Date: Mar 2010 Location: Bangalore Posts: 10 Thanked: 0 Times	Hi, I recently bought a 2002 model MM540; the vehicle seemed to be in good condition until the AC was installed. Please read the below time line. January 2010: Bought the vehicle (no AC), checked thoroughly by a mechanic and deemed to be in good condition. Temperature gauge constant at just below 80 deg mark, sometimes 85 - 90 deg in heavy traffic or when climbing a steep incline with 4X4 engaged. February 2010: AC installed; everything seemed fine. After a couple of days though, started noticing the temperature needle dangerously close to the red mark. Switching off the AC makes the needle go back to just below 80 deg. However, after a couple of days, switching off the AC would result the needle to drop to 80 deg (not just below 80 deg mark). Noticed that radiator was losing water; obvious culprits were either loose hose connections or faulty radiator cap. Found out that radiator cap wasn’t original but couldn’t procure one; it seems that all spare part shops stock duplicate radiator caps worth just 25 bucks. Another strange thing noticed was that the temperature needle flicks back and forth between 80 deg and 100 deg when the clutch pedal is depressed and released. The obvious inference was that either the temperature gauge was faulty or there was some sort of a loose connection in its wires. Time was running short so decided to drive down the vehicle to Bangalore from Kerala without using the AC, and check with a good mechanic after reaching here. AC details: Sandem 507 condenser with Unicla blower (excellent cooling). Condenser fitted in front of the radiator. Electric fan fitted behind the condenser; the fan sucks in air through the condenser. March 2010: Drove Vehicle to Bangalore, no problems encountered on the way. However, during the Ghats section (Nilambur – Gudalur), the engine temperature reached close to the red mark, but since the faulty temperature gauge problem still existed, while depressing the clutch pedal to change gear the temperature gauge needle flicked back to around 90 deg. Also, noticed that the exhaust was smoky so eased the accelerator pedal a little to reduce dumping unnecessary fuel into the cylinders, this bought down the temperature to 80 deg. After a week, consulted a couple of mechanics here in Bangalore, all of them concurred that one problem could be the electric fan being installed behind the condenser. Their logic was that since the fan was sucking in air through the condenser, which is an obstruction, the fan’s effectiveness is questionable. And moreover, the hot air that the fan sucks in is then released towards the radiator, where it gets sucked through by the radiator fan. Now, by placing the fan in front of the condenser, the fan tries to push the air past the condenser; some of the air goes through the condenser while the remaining goes around it towards the radiator. Therefore the radiator will get cooler air in front of it. Replaced radiator cap with original one; no lose of coolant after that. Mechanic confirmed that there was a loose connection in the electric wire to the temperature gauge. April 2010: Vehicle given to workshop with following instructions: Install fan in front of the condenser. Overhaul radiator. Add a reservoir to the cooling system. Fix temperature gauge. I got back the jeep yesterday evening. During the drive back home, the temperature hovered between 85 and 95 deg (AC in full blast). The needle indicated 95 deg (maybe 90 deg, can’t differentiate) in bumper to bumper traffic. Once the traffic reduced and got a stretch of open road, the temperature started dropping to about 85 and stayed there (the temperature would eventually increase due to bumper to bumper traffic). There seems to be obvious improvements, but is this enough, or is there more scope for improvement? If yes, what needs to be done. I hope I have given enough information for all gurus out there to nail the problem. Hoping all of you guys reply. Thanks
	() Thanks

13th April 2010, 19:47	#48
akm225 Newbie Join Date: Mar 2010 Location: Bangalore Posts: 10 Thanked: 0 Times	Hi DesertKing, Thank you for replying. No, my 540 doesn't have a thermostatic valve. Thanks
	() Thanks

14th May 2010, 16:14	#49
Tejas@perioimpl Distinguished - BHPian Join Date: Sep 2008 Location: Bombay Posts: 4,423 Thanked: 9,581 Times View My Garage	I'm planning to do a couple of dashboard modifications to my classic and also have planned an AC install in the near future. The dashboard mod is basically extending the dash to have a center console extending all the way till the handbrake with a lockable compartment. I may relocate the handbrake to the right of the driver and free up more space (still considering this though). Since i am planning the dashboard mod first, is it possible to just install a blower first and use it as a fan and do the AC install (compressor, etc) at a later date? This is important so that my dash can be sculpted around the blower. Also, which blower is recommended?
	() Thanks

14th May 2010, 16:36	#50
Gypsy-Boy BHPian Join Date: Mar 2009 Location: Bengaluru Posts: 298 Thanked: 9 Times View My Garage	Superking - its one of the best blowers you can find!! Am sure lotsa people here will say the same!!
	() Thanks

14th May 2010, 20:52	#51
Jaggu Team-BHP Support Join Date: May 2004 Location: Bangalore Posts: 20,212 Thanked: 15,892 Times	Superking or National, they have the best blowers. But i don't think it comes without the cooling coil assembly. Don't buy second hand stuff, buy a new one and wrap the coil inside with plastic so that dirt doesn't settle in till you complete the fitment of AC. Key is finding the right size compressor, most often people install oversize compressor which are a drag on the engine and results in heating. For a classic put a 505 compressor with a plastic partition behind the front passenger area. Also remember to do good insulation at the firewall and the floor area. 507 might not really be required for such a small area.
	() Thanks

16th May 2010, 23:58	#53
Jaggu Team-BHP Support Join Date: May 2004 Location: Bangalore Posts: 20,212 Thanked: 15,892 Times	Have you seen the sound deadening and heat insulation patches on the floor of modern cars, just lift the carpet and check you will know what am talking about. Use it, you need to heat and stick it, lil expensive, but will take care of all your concern points.
	() Thanks

18th May 2010, 19:43	#55
Jaggu Team-BHP Support Join Date: May 2004 Location: Bangalore Posts: 20,212 Thanked: 15,892 Times	Should be available with any of the big spare stockist in the city. Its not a fast moving part so might have to order and wait for it. This is a universal product only the shape of the patch will defer from vehicle to vehicle. Trouble will be to identify the biggest piece available, this can be then ordered and then cut and pasted based on the requirement. Also i have heard that 3M has the product, so a quick check with 3M dealers might help.
	() Thanks

18th May 2010, 19:46	#56
sreerajunnithan BHPian Join Date: Jun 2006 Location: Banagalore Posts: 445 Thanked: 11 Times	What's the technical name of this thingy? --Sree--
	() Thanks

18th May 2010, 20:01	#57
Jaggu Team-BHP Support Join Date: May 2004 Location: Bangalore Posts: 20,212 Thanked: 15,892 Times	I have no idea of the name, it should be sound deadening pitch or something of that sorts. Its used for sound deadening and heat insulation on floor panels of the chassis.
	() Thanks

18th May 2010, 21:27	#59
Jaggu Team-BHP Support Join Date: May 2004 Location: Bangalore Posts: 20,212 Thanked: 15,892 Times	aha and all this while you were just watching eh!! so how does it work for heat insulation?
	() Thanks

18th May 2010, 21:42	#60
SPIKE ARRESTOR Senior - BHPian Join Date: Nov 2009 Location: Germany Posts: 2,854 Thanked: 1,532 Times	Hehehe, as I told you earlier it is basically a sound deadening material the only protection it provides from heat is because, it acts as a layer between the heat conducting surfaces. You would find "melt sheets" mostly in the passenger compartments where better NVH levels are required. Moreover, heat sources are less under the passenger compartment. A component which prevents a majority of those heat radiations is the "firewall" which has a material with good heat resistance. Spike Last edited by SPIKE ARRESTOR : 18th May 2010 at 21:45.
	() Thanks