Repair Plan and Parts

• At a minimum, replace the compressor and condenser – filled with correct PAG 100 oil ($10), evacuate and recharge with fresh 134a refrigerant ($36). For parts, DENSO is the OEM for the ML350. Called DENSO to order correct model, but they were out of stock. Gave me a DENSO part number that Pelican Parts had in stock with a new oil filled compressor for around $380 plus tax/ship. Ordered a BEHR OEM condenser from Pelican for $246. IMHO – always replace the condenser when a compressor fails because it sends particulate downstream to the small passages of the condenser. This condenser came with an installed dryer/fluid reservoir. A new dryer/fluid reservoir needs to be installed every time the AC circuit is opened. I also go with quality parts that may cost a bit more, but figure the labor savings makes up the difference by quite a lot. Saying that, I skimped and got a universal AC O-ring pack, and wound up re-using one O-ring for failure to heed my own advice. Cleaned, oiled and re-used all of the black bushings at the end of hose connections in series with O-rings.
• Since the root cause of the AC failure was the radiator suction fan, and the 11 year old ML350 had 163,000 on the clock, decided to replace this component as well. Not found on PartsGeek, or PelicanParts; so looked on FCPEuro and OEM Parts.com. OEM was definitely less expensive than FCP, but still spendy at $468. Considered the replacement to be good insurance to avoid repeat failure.
• Got all of the instructions available for this model on R&R compressor/condenser. (Shout out to 43sqd). Workshop instructions are a good starting point, but do not include the nuances needed for success.
• Bonus points, replace TX valve and install a filter. (As it would turn out, the TXV is buried in the firewall, and I missed the sequential steps to install a filter in the high pressure line to the TXV). Since there was only minimal pressure difference between the high and low pressure line readings (which indicated no clog), I elected not to install the new TXV and filter. I estimated the TX valve replacement would have been 4 hours and caused a very bruised forearm and the expulsion of bad words. The TXV was one of those things in the universe you can look at OR touch, but not both at the same time. Turned out to be the right call to not replace the TXV.
• Concurrent maintenance – since the power steering pump came out for this job, we replaced the $4.95 O-ring between the reservoir and the pump sourced at the dealership. An extra 30 minutes to eliminate a pesky long-standing leak. Replaced the power steering fluid with Pentosin CHF. The serpentine belt also comes off for this work scope – but it was only a few months old MB brand so it was not replaced with new. Have replaced a compressor on a 2WD ML320 before from the bottom, but the ML350 4Matic eliminated the ability for this approach – so a top down view was needed with removal of the PS system.
• Having done this before on a different ML, I estimated about 18 hours from start to cleanup considering my advanced age, deteriorating mental acuity and declining physical capabilities. About right, with 60/40 split between the condenser and the compressor, coupled with reading instructions and the occasional nap. How the indy shop boys do this for much less can only be explained by the breakage a customer never sees until it is too late. That, and a garage lift would help a lot. Most probably they don’t replace the condenser. (or even the dryer). For the first time, no beer was harmed in the making of this type of blog.
• Not performed – a flush of the remaining installed AC system circuit hoses and evaporator. I have done a home flush before and it was such a bloody mess with so little particulate recovered, swore never to do it again. A risk to a new compressor, but with a new condenser and dryer/fluid reservoir took a chance on reliability. If the TX valve showed signs of clogging may have reconsidered. My last compressor replacement was done with no flush and is still going strong. We will see.
• Environmentally responsible – A local indy shop will evacuate the system for $30 (but keep the R134a) - so do environmentally responsible thing and get the R134a removed.

 

Tools used

Internal Torx 1/2 inch socket set or T25 driver at the very least
External Torx 1/2 inch socket set for use of E12 socket.
½ inch universal joint for socket set
1/4 inch rachet, extension, and 10 mm deep well socket,
10 mm socket box end ratcheting wrench (DIY could not be done without this tool)
17 mm socket with 3/4 inch rachet or breaker bar (for fan belt tensioner and wheel studs)
6 mm Allen wrench or socket for AC hose connections
hand held battery powered ½ inch ratchet driver
3 inch and 6 inch socket extensions
½ inch Torque wrench calibrated to 20 Newton Meters
Standard Pliers
Vice Grips
**** cutter for horn ty-wraps
Two new ty-wraps for horns
T25 Torx screwdriver
Small blade standard screwdriver to pry off PS C-ring and compressor solenoid plug
Trim removal pry bar (to remove plastic rivets)
small inspection mirror
magnetic pickup
wheel stud locator
jack stand
wheel chocks
hydraulic jack
safety glasses
shop light
paper towels
Bungee cord
A small grey ferret
Industrial plastic syringe graduated in ml for adding PAG oil
Oil catch basin
Large pitcher for holding hot water
Compound gages/manifold/hoses for AC
Vacuum pump
AC can metal valve
Drift pin, or awl, or nail punch to center up bolt holes during reassembly.
Rubber mallet (or rubber chicken might have worked)
Ball peen or claw hammer
18 egg carton and felt tip pen to keep track of all of the fasteners (removed eggs first)
lots of latex gloves
Garage ventilation fan
An old pillow to lay my head on while working underneath the SUV
And a roll around stool to sit my tired arse upon

 

Very Important must do TIPS

I knew that surgical cleanliness for the inside of the AC circuit is key to lasting repair. Cleaned any accessible connection before taking apart. (Brake cleaner will work for hard to reach points) Wrapped ends of hoses with Saranwrap for FME controls. Used plenty if oil on O-rings before reassembly. Compressor needed to be turned at least ten revolutions (by hand) before final installation and engine start. Set a flag reminder to check hood latches operate properly after cross beam reassembly (Fortunately, I DO NOT have the T-shirt for that last potential snafu of inadvertent disabling of latch release and then closing the hood).

SAFETY

• Use of a jack stand under a cross member is mandatory in my book whenever jacking a vehicle. Same for wheel chocks.
• Safety glasses are a must.
• When starting a car in an open garage – a strong fan is required for good ventilation.
• On the other hand, shop instructions all said to disconnect the negative battery terminal. For what? Keeping the key out of the ignition kept the compressor and radiator suction fan electrical connections de-energized. And I lived to blog about my careless disregard for electricity.

 

Started by Clearing the workspace in engine bay

• Removed the top plastic front engine cover. The two snorkel hoses came off, but the backside air cleaner housing stayed clamped on.
• Removed the front grill and two horns.
• Unbolted the cross beam over the radiator, unsnapped the hood latch release lines from underneath, set cross beam aside.
• Unplugged the radiator suction fan connection on the passenger side. Unbolted the top two left and right 10mm bolts holding the fan housing to the radiator. Pulled fan housing straight up and to the left around radiator hose.
• Removed serpentine belt. (It is possible to use the tire iron on the 17mm bolt/stud when detensioning.)
• Removed the power steering pump.

 

Power Steering Pump and reservoir

• With the front wheel drive transaxle taking up so much space down below, the only way we could access the compressor on the 4Matic was by removing the power steering pump and reservoir.
• The plastic reservoir is attached to the engine block by three front-facing easily accessible T25 bolts that are captured in the plastic housing. The metal housing of the pump is fixed to the engine block by three E12 torx bolts (and can be removed with a 16 point 10 mm socket). Two are on the front, one of which can only be accessed by pulling counterclockwise on the serpentine belt tensioner to clear the bolt view. (using a 17mm socket or MB tire iron). The third bolt was shy and could not be seen because the bolt head faced the driver and was located on the backside of the pump and below the OH cams. After much groping and griping, found the bolt and captured the head with a 10mm ratcheting box end wrench. It is the only way to get to this bolt short of pulling the engine. I have long arms, but my forearm barely fit between the ABS pump manifold and the power steering pump/reservoir to achieve 1/8th turns of the ratcheting wrench. Next time, I will tape a string to the wrench in case it falls into the abyss of the engine compartment. (Got the T-shirt for that snafu.)
• We hung the reservoir from a bungee cord attached to the engine block lifting eye and then vacuumed out the fluid with a Mytivac. (Should have done that prior to removal – but no fluid spilled and no foul this time.)
• Now we had room to see the top of the compressor, high and low pressure suction lines, electric start connection, and one of the three compressor hold down bolts. (The other two compressor bolts were now be accessible by wrench, but not seen.)
• The PS reservoir has a circlip to a return line connection that we left in place. We also left in place the banjo fitting from the pump to the steering rack. Both of these lines have high pressure hose that allowed some flexibility in moving the assembly. The O-ring to replace was the rigid connection between the reservoir and pump suction – held in place by a C-ring (aka Snap-ring). A flat blade screwdriver and pair of pliers was all that we needed to pull the C-ring. A minute later the old leaky O-ring was replaced with a new O-ring first lubricated with PS fluid. Reassembly of the C-clip was completed with the tap of a ball peen hammer.
• After the new compressor was installed and the system leak check was completed satisfactorily, the PS system was reinstalled and refilled.

Power Steering Pump Replacement Mercedes Benz ML500 1998-2005 - Bing video

 

Hey I’m replacing my 2008 e350 4matic and had to remove quite the amount of stuff you did. I was wondering if you put the power steering pump and reservoir back before doing a leak test with your new installed compressor. I am also replacing condenser so would it be best you believe to replace compressor condenser do a vacuum then reinstall the ps pump and reservoir?

 

Compressor removal and new installation

• With the top of the compressor clearly visible, unsnapped the single electrical connection.
• Unbolted the high pressure and low pressure hoses from the fully evacuated system with a 6mm allen wrench.
• Unbolted the three compressor housing connections. Rear one first (can be reached from above) and the lower front next, and the most visible top one last. Kept the old compressor upright because it contained PAG oil.
• Pulled compressor out from topside of the engine bay and set aside upright.
• Replaced the O-rings with new lubricated rings for the suction and discharge lines after cleaning the connections again.
• Turned new compressor by hand 10 turns and loosened (not removed) the top plugs (kept in place to avoid spilling PAG oil)
• Set new compressor in place and started top front engine block bolt first, front bottom bolt second, and back bolt last. Tightened to roughly right. Retightened.
• Reconnected electrical feed. Verified connector snapped in place.
• Removed compressor plugs and inserted AC high and low pressure lines. Tightened to 20 N-m. Retorqued. Admired the new shiny thing on the engine.

 

Preparing to think about removing the Condenser

• Removed the engine belly pan. (Between eleventeen and 20 bolts).
• Removed four underside bolts now visible on the front bumper.
• Jacked the driver front side and removed that wheel. Yes – removed the wheel to get to the condenser. (It is even more tits up from here on out.)
• Removed the front half of the wheel liner. Two 10mm bolts, three plastic rivets, and two plastic 10mm nuts. Now the fun starts.
• With the bolt head facing out, there is a horizontal 10mm bolt in a circular carrier that captures the lower bumper fascia to a brace on the body frame. The only way to loosen is with the 10 mm ratchet box wrench. The circular carrier pulls back to set the bumper free of the frame.
• Removed the T25 screw from underneath the clamping bar between bumper and fender. Using a flat bladed screwdriver, pried open the clamping bar. It fell to the floor and the bumper was set free of the fender.
• Meanwhile, up top, unbolted the innermost 10mm long bolt for the headlight which also captured the bumper fascia to the body. Pulled up the fascia to free it from the peg. Another 10mm bolt previously removed for the cross beam released the windshield washer fill spout. With the bumper fascia now loose and giving room to operate, the washer spout was pulled up and out.
• Tugged on the front of the bumper until it came forward on the driver’s side 6 – 8 inches (still clamped on the passenger side and bolted by the other headlight.)
• Back in the fender well, set a support beneath the washer reservoir. (jackstand will work) Unbolted two opposite facing E12 torx bolts to free the reservoir from the real metal bumper. Set reservoir on temporary stand because I was too lazy to disconnect the electrical or even drain the blinker fluid.
• Underneath, while lying on ones back, there is a 10mm bolt connecting the plastic windshield reservoir to the body frame that had to be removed to reveal the condenser connections.
• Next, a thin metal backet previously captured by the reservoir bolt just removed had to be bent aside to reveal the prize of this quest – a 10 mm bolt that connected the condenser to the radiator.

At this point, I could only admire the abject stupidity of the sadistic engineer who thought this spot to be a good idea for deeply burying such a magical and critical bolted connection. I wistfully hoped he was stuck working at Fiat-Chrysler design basement now, and that made me feel better. Better yet – demoted to an AC repair mechanic.

 

Condenser Removal and new installation

• Just above and behind this magical condenser bolt was a perpendicular 10mm nut facing forward on a stud that connected the two lines from the condenser to the rest of the system. This nut had to be removed to partially free the condenser. Didn’t want to lose this puppy because I had no spares with a specialty land facing.
• At the bottom on both sides of the condenser shroud were 10mm bolts facing forward that clamped the assembly to the radiator. Removed these hard to reach connectors and unbolted the fasteners.
• At the top on both sides of the condenser shroud were two forward facing 10 mm bolts that clamped the assembly to the radiator. Removed.
• Now that the condenser and its shroud were unbolted from the radiator, it was time to begin the wrestling match. After separating the condenser/shroud from the radiator at the top and freeing the metal condenser ‘ears’, pulled up on the condenser to free the two bottom ‘ears’. I kept the radiator hoses on because of stubbornness, so had to shake and weave the condenser to pull it out all of the way.
• Vacuumed all of the crap that had accumulated between these two heat exchangers and underneath the radiator. This debris meant I had to pay attention on reassembly to avoid a poor fit between the condenser shroud and radiator to avoid more crap sucked into this annular space.
• Filled the new condenser with 10 ml of PAG oil at the connection to the attached dryer/fluid reservoir. Then added another 5 ml for good luck. (which I spilled during reassembly.) Replaced the FME caps on the condenser to prevent spilling PAG oil. (And then knocked one off during reinstallation, hence the spillage. Glad I put in a few extra ml.)
• Now the system was leak tight. Performed a preliminary system evacuation and leak check. Which was good. (yeah baby!)
• Reassemble in reverse of the steps above after satisfactory leak check. (Except do not put back the crap previously vacuumed up or drain the PAG oil.)
• Tips for reassembly of the AC line connections to the condenser dryer. A) Ty-wrap the two lines together and capture them snugly in the hold down clamp. Cut the ty-wrap once the lines are seated and the 10mm nut is tightened. B) Have a helper above to position the condenser when making the connections.
• Tip for attaching the condenser to the radiator at the magical bolt. Use Vice-Grips to pull the two components together and start the 10 mm magical bolt.
• Tips for installation sequence of the front bumper fascia after condenser and radiator are installed. A) Reinstall the windshield washer reservoir. B) Loosely set the fender fascia onto the frame peg at the headlight near the upper radiator cross beam. C) Used a hammer to seat the clip between the fender and the bumper. D) Used a rubber mallet to adjust the bumper and fender gap / alignment after inserting the bumper clip / bar set screw but before tightening the screw. (There are specifications on gap distances to achieve a margin of error within the length of a bee’s dick, but I just nudged the bumper fascia until it looked right.) E) Installed circular fastener between bumper and frame brace inside the wheel well. F) Installed the four bottom bolts of the bumper facia to the body. G) Tightened all remaining bolts that were loosely fastened.
• Tip for the radiator suction fan – ensure that the motor’s electrical connector is securely fastened to the shroud. I had to uninstall because this connection was loose. Minor PITA.

 

System Evacuation and leak check

Years ago I purchased a set of compound gauges and a cheap ($125) vacuum pump. Nowadays, you can get a ‘loaner’ set from AutoZone or O’Reilly’s.

As soon as the system connections were leak tight, I ran the vacuum pump for 30 minutes and did a resting system leak check over an extended 90-minute lunch. Did not want to reinstall the Power Steering pump, seat the condenser or reinstall the front bumper until there was assurance that the connections were tight.

Only then, to avoid having rework, did the reassembly of other components begin. During reassembly of these parts, ran the vacuum for another hour to get the remaining moisture out of the system, and let it sit overnight for a second check. In the morning, the vacuum was perfect, and I ran the pump for yet another hour – overkill to remove moisture and just because the bumper still needed reassembly.

Build it back better

• Now was the time to reset the Power Steering system and install the serpentine belt.
• Before bolt up, ensured the condenser shroud was positioned roughly right, and that the bottom ‘ears’ of the condenser were set into the radiator keepers. Repeated for the top ears and keepers.
• Next, was the reconnection of the four bolts for the condenser shroud to the radiator.
• Then, radiator has two legs that vertically set into the cross frame underneath.
• Back goes the upper cross frame. The radiator has two upper ‘hands’ that set vertically into the upper frame. Bolted that puppy up. Before going any further, did several checks of the hood latch – using a flat bladed screwdriver to activate the latches, and opened with hood release. Good to go.
• Installed the horns.
• Installed the washer fluid reservoir.
• Installed bumper.
• Installed fender liner and wheel.
• Installed the two snorkels and the front plastic engine cover.
• Installed the underbody ‘diaper’.

 

System Charging

This was the point of where doubt crept in. What did I miss in reassembly? Was the diagnosis correct? Are the parts correct? Will the system work or slowly leak over time? Real mechanics don’t have these insecure thougths.

Underneath the hood on the front cross bar is a decal that indicates how much R134a to add for a given system. The ML350 spec was 2.2 lbs +/- 0.04 lbs. To get to that measurement, using a $14 digital scale from Amazon, weighed a full can plus a valve stopper to get the integrated weight, and then weighed a discharged can plus valve. (Repeated process to add the correct weight and fully charge the system.)

The first can of R134a went in with the AC compressor turned off but the engine running. (The compressor hub still spins with AC button off.) My compound gage has a check valve in the fill/vacuum line so I did not use the old mechanics trick of purging the line before adding refrigerant. I held the can upside down to have the expanding gas push liquid into the system before opening the manifold valve to the low pressure suction. Using a large pitcher of hot water, then immersed the upside down can to heat up the isothermic reaction and further empty the can and system pressure stabilized between 70-80 psia.

With a partially charged system pressure above the low pressure compressor cutoff, we started the AC system. The radiator suction fan started as expected, and the compressor drew suction down to 30-40 psi and emptied the first can even further. I had the AUTEL OBDII computer handy in case we needed to reset any AC fault codes for the compressor, but none popped up. Next, we put in the second can in a similar manner. Cold air started coming out of the passenger side vents (expected since the R134a expands in the passenger side of the evaporator first). By the time we topped off the system to fully charged, both the driver and passenger side were blowing chunks of ice and making my nipples cold.

We demobilized the charging system. Then checked the Power Steering fluid now that the pump had been run, and topped off that reservoir.

Hope you enjoyed the read.

Merry Christmas!

Atom smasher

 

Wow. Thanks. Wow.

 

Just an unbelievable write-up. Not something I would ever think of handling. Interesting however in as much as my 2009 ML 350 is right now at the dealership getting the condenser and compressor replaced. I am paying $1800. Do you mind telling me what you paid all-in for the work that you did? I'm thinking from reading your post that you paid about $800?

 

Thanks for the feedback wayaboveme. This is my third MB AC replacement rodeo, so I already had some of the essentials handy (such as compound gages). Parts for the compressor and condenser were roughly $700 new OEM. The radiator suction fan was a separate item that I replaced concurrent with the work.

• At a minimum, replace the compressor and condenser – correct PAG 100 oil ($10), evacuate and recharge with fresh 134a refrigerant ($36). DENSO OEM new oil filled compressor for around $380 plus tax/ship. BEHR OEM condenser for $246.
• OEM Radiator suction fan at $468.
• Concurrent maintenance – since the power steering pump came out for this job, we replaced the $4.95 O-ring between the reservoir and the pump sourced at the dealership.
• Environmentally responsible – A local indy shop will evacuate the system for $30 (but keep the R134a) - so do environmentally responsible thing and get the R134a removed.

For dealership work, $1,800 sounds pretty reasonable.

What did they say was the cause of your AC failure?

 

Thanks for the feedback wayaboveme. This is my third MB AC replacement rodeo, so I already had some of the essentials handy (such as compound gages). Parts for the compressor and condenser were roughly $700 new OEM. The radiator suction fan was a separate item that I replaced concurrent with the work.

• At a minimum, replace the compressor and condenser – correct PAG 100 oil ($10), evacuate and recharge with fresh 134a refrigerant ($36). DENSO OEM new oil filled compressor for around $380 plus tax/ship. BEHR OEM condenser for $246.
• OEM Radiator suction fan at $468.
• Concurrent maintenance – since the power steering pump came out for this job, we replaced the $4.95 O-ring between the reservoir and the pump sourced at the dealership.
• Environmentally responsible – A local indy shop will evacuate the system for $30 (but keep the R134a) - so do environmentally responsible thing and get the R134a removed.

For dealership work, $1,800 sounds pretty reasonable.

What did they say was the cause of your AC failure?

At this point, they are saying intermittent failure of condenser/compressor with no reason why. They originally thought I had a leak somewhere so they evacuated the system, put the dye in and then re-filled the system and confirmed it was working. I then picked the vehicle up and while driving away, noticed no AC so back in it went and then they realized the intermittent failure.

 

Sorry to hear that they did not know the root cause of AC failure. Might be an electrical control signal. In my case, it was the radiator suction fan as the root cause. AC worked upon immediate startup, then went hot with no air blowing across condenser. (At least until the compressor bit the big one trying to operate like this)

You can still press them for DTC codes before they want to charge you with an expensive controller when all that is needed is a new system pressure cutoff switch.

Smart decision to not take the bait for $1200 wheel repair sensor - easy DIY. I usually clear the fault codes before driving, not sure if you have to, but if you are not successful at first that could be the problem. BTW - they do usually go bad in pairs in short succession.

 

Atmsmshr I just replaced my compressor on my 2009 ml 350 4matic this sunday and was able to remove and reinstall it with out taking off the PS. My arms paid the price as did my fingers but my AC failure was the bearing failing and the flex plate breaking on the pulley. Once I got it all back together I tried to load the Freon in to the system and my compressor would not engage. These compressors don't appear to use an electromagnetic clutch like the old days but instead use a solenoid valve to activate the unit. The compressor is always turning but no work or compression is being done because the solenoid valve is open but once it gets 12 volts the valve closes and compression is possible. Now on my truck I was not able to recharge the system like you were able to. I could not get the 12 volts to the compressor even though the ac control system seems to be just fine so I ran a jumper with a 3 amp fuse and loaded my system. Now, however, I have a fully charged system and no loading on my compressor. Reading your post and several others it appears that the ac control unit may need to be cleared of an error code in order for the compressor to work. You did make mention that you had a scanner ready incase you needed to do this but did not mention which one. I have seen some links to md808 or md806 but none specify that it resets the ac control unit codes. I believe I need to reset mine as the failure happened when my wife was driving and the ac was running at the time. I believe the unit detected the fault and I need to reset it. Thanks for for your help...

 

Ezra - I don't know if it will work, but try disconnecting the negative terminal of the battery for a few minutes if you do not have immediate access to a shop grade scanner to clear codes. You are correct in that this style of compressor appears to spin all of the time - loaded or not. Atom

 

There are many scanners that can do this. Just look for one that does "all systems" for MBZ vehicles. Some options include iCarsoft (MBII, i980, v2.0, v3.0), Foxwell n510 Elite, and the Autel Diaglink. The Autel MD808 Pro and MD806 pro will work, too, but they come with software for "all" cars. If you will be working on other makes, you might consider them (they are identical except in color).

 

Albeit the disclaimer, I’m about to take on the same task and have a couple of questions. I have a little past experience doing AC and car ac work, but it’s dated. These newer variable displacement compressors are a little difficult to diagnose.

I’m having approximately the same readings - a little over 100 on both the low and high sides. No change whether the ac unit is on or off. So I know the compressor is not pumping.

No fault codes are being generated. I did replace the solenoid valve in the compressor, but no change - although I could not fully charge back since the compressor won’t pump.

Later (bad timing) I figured out how to check the voltage at the compressor solenoid. I’m getting 12volts with the system on, zero volts with it off, so I’m pretty sure the controls and signal to the compressor are correct - which probably explains the lack of codes found by the scanner.

I do wonder about the cause - my fan seems to be working correctly, but I recently replaced the water pump and removed the fan for access (I.e. unplugged it and replugged it) so I didn’t observe its operation beforehand. Will keep an eye on that for sure.

So my question were about parts:
Regarding the oil, the under hood label has the MB part number for the oil (ridiculously expensive) but I can’t find a good way to cross that over to the correct PAG oil type. The Denso install instructions call for “ND-OIL 8” which their website calls PAG 46. I believe my 2010 ML550 uses the same Denso compressor. Mine calls for the Denso 471-1594. Just wondering how you settled on the PAG 100 and if you know of a site that would confirm the application.

Which brings me to my other question - for that compressor, Denso is again out of stock on the 471-1594 @ the good price point of $380. Pelican is at $680, with other suppliers varying but all at least $480ish. Any tips on how you got Pelican to do the $380 price on the compressor?

 

Please EDIT your post in that the Denso compressor part # is incorrect.

It should be 471-1594

 

Good catch

 

MJM550 - Sorry to hear that your ride has no AC at the height of summer.

Regarding which replacement compressor and cost through parts supplier - DENSO customer service provided me with the model change number for ordering.
Regarding the compressor price point - it is what they ask for. Supply shortages everywhere.
Regarding compressor PAG oil - I could not find a MB approved translator from the BEVO pages to a standard PAG number. The 100 quoted is what the new DENSO compressor was filled with, and a few other non-MB supporting articles. No guarantees in life.

Suggestion - Check to see if your aux fan rotates freely with the engine off and the fan starts concurrent with starting the ML and the AC button pushed in. If not, check the pin on the socket for power. (I did not do this step - just jumped to buying new).
Suggestion - Sounds like you have eliminated power to the compressor as a problem. Bite the bullet and replace the condenser concurrent with the compressor. The condenser should come with a new dryer - but verify in any purchase.
Suggestion - O-Reilly's and other auto retailers have 'loaner' vacuum kits nowadays. A good bargain for the shade tree mechanic.

Don't forget to be environmentally responsible and spend the $25 to have an indie AC shop evacuate the refrigerant.

BTW - The 4Matic in the starring role of this blog is still blowing ice cubes this summer.

Good luck,

Atom

 

Awesome write up. Thank you for doing this. 2007 320 CDI. Smoked a belt. PS pump pulley jumps around when running so thinking intermittent pump lock up but a bit hard to tell. Once diagnosed, I'll write this one up, as well.

 

Might be of help to