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What is an automobile? Is it a mode of transportation, or is it an object that defines our personality and who we are? For most of us, it is a combination of both. However, there are variables that influence the decision about which make and model we will drive. The cost of acquisition and maintenance, in most cases, is the limiting factor. Often times, the maintenance consideration is neglected. Our objective is to educate and provide a facility which makes owning a high calibre vehicle, such as Mercedes, possible.

Monday, January 16 2017

     This title is, of course, an analogy for basically buying an automobile without a proper inspection. With all of the inter-related on board systems (computers), complex suspensions, catalytic computers, convenience systems and more, it is without a doubt necessary to perform a pre-purchase inspection from a qualified (that is, a facility that works on Mercedes) business that has the proper diagnostic equipment and is familiar with the weaknesses of the model that you are considering purchasing.

     There are 2 checks (among the others) that need to be performed. First, you must put the car on a lift and thoroughly inspect the suspension, drive line, exhaust, and integrity of the chassis. Without exception, if there are no problems underneath the car, there will be very few elsewhere. This means that the owner has regularly serviced the vehicle and has done the needed repairs. If the repairs have been performed underneath, the individual has done whatever repair needs to be performed.

     The other inspection that can be done is to do at least a short test on the Star Diagnostic System and get a good idea if there are any problems lurking in the future. There are 3 areas I would pay very close attention to. First is the secondary air injection system, second is the transmission, and third is the AC system.

     The secondary air injection system's purpose is to make the engine run cleaner (less pollutants) upon start-up. Carbon build up in the cylinder heads prevents this and the presence of this problem is a deal killer because it is so expensive to fix.

     The second item, the transmission, is overlooked on the older Mercedes because it was not a regularly serviced item. Mercedes stated "the transmission has a lifetime fill" which meant you never had to service the transmission. This policy started in 1997 with Mercedes first electronic transmission and continued through 2006, until the advent of the new 7 speed transmission. The Star System can unveil any potential problems here.

     And, finally, the AC system. The biggest (most expensive) problems would be a leak in the evaporator. A visual inspection some times can detect a leak from the evaporator. Sometimes you must charge the system using oil with dye. But remember, if the AC does not work you must assume the worst. The owner's assurance that it just needs to be charged with freon underlies the fact there is a serious problem.

     Finally, responsible owners will keep records! You want to see a dossier of records that would choke a horse: verifiable records (this means that you call the shop) on the car to be purchased. I would easily pay a $1000 premium for a car that has meticulous service records. Buying a good used car is difficult and time consuming but you can weed out potential prospects with a couple of questions: How long have you owned the car (at least 5 years) and do you have extensive verifiable service records.

     Finally, if a car meets the original criteria, schedule a pre-purchase inspection.

Posted by: Ken AT 01:40 pm   |  Permalink   |  0 Comments  |  Email
Tuesday, January 03 2017

     Arguably Mercedes air conditioning systems have left much to be desired. One can argue that with the moderate summer climate of Germany and with the engineers focused on quality, performance, and safety, the HVAC systems may have been overlooked.

     The first Mercedes imported to the U.S. in the 1960's did not have air conditioning, and if you did wanted it, it was an afterthought. This included a hang-down inside unit and an almost home-made engine bracket to accommodate the inefficient York compressor. No auxiliary fan to cool the condenser was available until the early 1970's. Early AC and heat controls were strictly manually controlled with a blower speed control switch and a switch for temperature adjustment. A lever would control the direction of air flow, i.e.,whether warm air would go to either your feet or the windscreen. Manual controls are okay for most as long as the desired effect is realized. Heating was okay, but air conditioning left a lot to be desired.

      As the U.S. became more important to Mercedes sales, MB USA needed to respond to the demands for climate control systems for the U.S. market. The first "climate control" system for Mercedes debuted in 1976 in the S class 116 chassis 450SE, SEL and the 280S. The fact that this system was only used in the U.S. market provides evidence that the engineering strength for climate control systems by Mercedes left a lot to be desired. As a result, the CC system appeared as a convoluted system which was expensive and unreliable and this continued through 1981. In 1982 the climate control system was completely changed to a much more reliable and inexpensive system.

     One would think that the heart and soul of any cooling system would be the compressor but I strongly believe that for a Mercedes owner, the evaporator would be the most important. The evaporator is the device inside the dash which gets cold and provides the cooling inside the car. There are no moving parts to break, just a piece of metal about the size of a loaf of bread, with small tubes and fins to help dissipate the cold provided by the freon.

     The evaporators of most Mercedes through the 1980's were made of brass and copper and very seldom failed. Automobile manufacturers are always faced with government mandates to improve fuel economy, which means weight is always a consideration, and the durable copper based evaporator was replaced with aluminum as the base material. Unbelievably, the model which suffered the most from defective evaporators was the high line S Class models, of which many were priced above $70,000. This evaporator replacement is very expensive (about 25 hours of labor) and with about $800 in parts, at a dealer it would total well over $3000.

     With this in mind, what percentage of these evaporators would fail within 10 years? Unbelievably, it is close to 100%. Why would this part, a part that is so important and costly to replace, be so poorly designed?

     So what do we take away from this blog/article. If you are purchasing a W140 chassis car, you must check the evaporator for leaks. The fact that the AC is operational is not enough. (It may be a slow leak.) When you do a pre-purchase inspection, make sure you check the condensate tubes for dye which is from the refrigerant oil. This is always a tell tale sign of a defective evaporator.

     Good luck and make sure you do your pre-purchase inspection due diligence.


Posted by: KEN AT 02:08 pm   |  Permalink   |  0 Comments  |  Email

The Benz Store specializes in the early mechanical speedometers, and early electronic S-Class 1981 and newer and SL Models starting in 1981 thru 1995 on most models. 

 Mechanical repair $75.00/Exchange.

Electronic $95.00/Exchange and the correct mileage it provides.

2 Day Turnaround. Email any questions.

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4321-C Buford HWY | Chamblee, GA 30341 | Phone: 800.631.4170 | Email:
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