Do all older cars have mediocre ventilation systems??
 

I love vintage cars....the styling, build quality, ease of maintenance, and more are just some of the reasons I prefer old vs new...I'm an engineer...I work with technology every day, but when a late model car with multiple computers pop up warning lights because of this sensor or that, or go into a limp mode or whatever, I really get frustrated. Late model cars are great when all works well...when something fails, it can be a challenge pulling codes, trying to find an intermittent fault, and of course costly.

One thing cars from the 80's onward have that is great is the heating and air conditioning...strong blowers and a lot of registers...my question today for all of you, is how did people deal with, and accept, the substandard ventilations systems in the early cars? I have three Mercedes...my 300D ventilation system is great...well, the automatic mode and manual two speed fan could be improved, but otherwise is very good. But on my 1969 280SL and my 280SE, the air doesn't blow, it just wafts out...the levers aren't marked well and are a mystery how to adjust like some WWII Enigma machine...the under dash A/C is OK, but the heater and defroster are so bad. What do you think?

I guess I would still prefer manual control of heat. It is easy to find a comfort point. I believe however that when t was finally decided that under-dash or trunk-mounted air conditioning was not desirable and we wanted the ac to blow out of the same vents as the heat, things started to get complicated.

One of the most comfortable ac units I ever had was in a 1956 Chrysler. It had a HUGE squirrel cage blower in the trunk that just blew low speed cool air through vents in the rear package shelf. It cooled the car thoroughly and quickly without a draft.

I prefer manual HVAC. I have a 300000 mile 2000 Silverado with the base HVAC and have never had an issue. My 130000 mile 2005 GMC Yukon Denali with a full auto system has failed multiple times with servo failure and control lockups.

my cars all thrive on 4-60 climate control. It's especially fun when the windows are hand the budget style hand crank kind. There is a well worn story of Jackie Gleeson hating the A/C in his early 60s Mercedes limo while driving in FLA. He invited two Mercedes Benz execs for a ride and they gleefully accepted and he made them sweat a while in the back seat. Soon after that, they added a whole separate A/C system in the trunk, accurately referred to as "the Gleeson A/C" system from that point on.

There are several variations in the heating and cooling technology in the 60s and 70s due to folks trying to balance noise, weight and efficiency of the equipment. At times they tried high-tech solutions like climate control where you choose the temperature and the car figures out if it should be on heat or cool. And plenty of times, the technology didn't fit the need well. Often it worked up front, but after time, the maintenance cost became untenable.

Mercedes had made some rather interesting design trade-offs over the years. The 60s limos have hydraulics controlling just about everything, even closing the trunk lid, but the maintenance cost is staggering. The hydraulic windows controls are totally effortless, fast and silent. It's exactly what a head of state would want. Then some later owner has to pay the bill to fix it, at thousands of dollars these days for the switches and tons of money for the hours and hours of labor, presuming you can even find somebody well trained to do the work. Why? Because small electric motors just weren't good enough for what was required.

-CTH

I owned and restored a 600 and did two more restorations since then. The AC in those cars was very good and worked perfectly.
Window lifts were amazing and very fast. I had a source for hydraulic cylinders at the time but have since learned that you can get them rebuilt. If you know hydraulics really well you can fix just about anything on the car. One of my guys rebuilt all of the door switches plus the main pump for a few dollars in parts - lots of time spent but they worked perfectly.
MB wanted as much interior room as possible and they also wanted to keep their door's weight as low as possible. Electric motors would have been heavy, bigger, taking up more room inside of the door, and also noisy.

Expectations have changed. Today we drive our cars with the windows closed at all times. In every sedan Mercedes up until the W123 the ventilation window was a feature that allowed for augmenting existing in-cabin ventilation. The W108/109 has wonderful ventilation if the car is moving. The moving car has clever air exhaust features that allows for the car to exchange cabin air well enough to keep the occupants comfortable until air conditioning is needed. Standing still the blower is indeed weak and noisy, but it will keep the windshield from fogging assuming its clean and the flow is dedicated up via the control. Also, assuming you have the correct thermostat for extreme cold weather driving and the heat control levers are working properly the system will warm the cabin very well. In middle Tennessee we typically do not seasonally change thermostats so I just bundle up when driving the car in temperatures below 10 degrees F.

For the driver (the most important occupant according to Mercedes) the dash vent on the far left(right for right side drivers) has a lever to allow for direct outside airflow. which while for the benefit of keeping the driver cool and alert it also serves as added anti-fogging for the side window.
The W100 600 first released in 1963 and the W111/112 released about the same time were the first Mercedes to feature the same ventilation tech found in the W108/109.

I totally agree the manual controls are better...I have never seen an automatic system that worked over the long term. One example is how I had to find a special control box to adjust servos in a Rolls Royce Spirit A/C system...Rolls boasted so much about this split system, but few ever worked correctly.

It's interesting and great to hear that some here on the forum were lucky (and brave) enough to own and drive a Mercedes 600...I'd love to see one someday...Jay Leno features one on his show, and it's amazing how fast and silent the windows move (kids and pets beware!). The trunk looks scary how fast it drops though...anyway, I would imagine the A/C was great on those. Is there a unit in the trunk for those? If memory serves correct, I think the 41 Packard had it first in the trunk, but no A/C clutch, so on all the time...and didn't the Lincoln Zephyr in the forties have hydraulic power windows? I thought Cadillac electric power windows in the fifties, so the motors must have been OK by them, so I wonder why MB didn't use them at that time. Going back to low flow ventilation, I just remembered my '66 Mustang has small lever controls like the 60's Mercedes...also, not a great air flow to defrost or warm you. The resisters on my 280SL are really really small...you pop them open with your finger...only the fresh air vents are larger...the registers on these cars was never big...then again, Rolls never had enough registers either in their early cars...

In my MBZ experience, the quality of ventilation is a matter of manual vs automatic climate control system. My W115 had sufficient venting - manual. My W123 came with automatic CC - poor venting. After changing to manual CC, which I did almost 30 years ago, the W123 had (and still has) very good venting, plus AC and heat function.

How did you make that change, may I ask? My W123 is automatic and I have either high or low and nothing really in between. I have to hit defrost and then switch to other settings to get the fan on. Temp sensor is fine, and I haven't had the time to pull apart the dash to look at the blend door servos and such. I would prefer going to a manual system. The solenoid valve in the heater line is bypassed using a ball valve, since it doesn't cycle correctly to maintain heat in the winter or A/C in the summer...like I said, an automatic system problem I haven't had the time to hit real hard. I guess when we collect more than one car, we pick and choose our battles given limited time and money!

It's a bit time consuming, but basically I removed the dash first, then R&R the entire box, controls, and AC housing with a manual system from the same year 240D. The automatic CC wiring harness is mostly separate, so not too problematic. As I remember, there were only two leads that I had to cap off. It was much easier to use a thermostat from a W115 while retaining the original W123 on/off dash compressor switch than to use the 240D thermostat system. Then all the vacuum lines and "evil servo" and associated water lines were removed as well.

I would guess that your problems stem from either the evil servo or a combination of the solenoid valves. The CC water pump also contributes to lack of heat problems. I can't offer much else on repairing this system, but there are others here who have successfully worked on it. Your way of thinking about this horrible system appears to be the same as mine - replace it with manual and have done with it.

Some observations.....

A/C in the trunk was always mounted between the rear wheels. Today on Mercedes, or at least starting with the 116 and 107s, the gas tank is located in that spot.

The trunk mounted A/c weighted about 45 pounds. That's a lot of A/C. They had to be in the trunk because in order to cool the entire interior as those old large cars you needed a giant unit. You could order a 600, or a Caddy, with a front and rear unit, a must if you had a divider window.

I once had a 1951 Studerbaker Champion. When you opened the side vents you had plenty of air moving through the car even with the windows up. Opening the vents and cracking the rear door windows was a common thing.

The heaters in those cars from the early 50s was usually a add on heater box in the passenger footwell. It would torch you out unless you were in the back seat and then you just covered up with blankets. The under seat heater vents on the 114 and 115 were considered amazing at the time.

The hydraulic windows on the 600 were that way not for weight but for silence. The speed was a function of the diameter of the window cylinder pistons and the pressure put up by the hydraulic pump. The pump had to put a lot of pressure to open the trunk lid so since Mercedes had the pressure they just increased the size of the window cylinders. Thus you got speed and lots of it.

By the way... If you do own a 600 and the windows move to fast for your taste you can install a valve in the pressure line to decrease the amount of hydraulic fluid entering the cylinder. This will cause the cylinder to fill and to drain at a slower rate thus slowing down the windows. With a small valve you can adjust the window speed to whatever suits you.

Electric motors then were also noisy since the power window motors they used were the same motors used on the 116 to open and close the sunroof. So if you know how noisy the sunroof motor is you can understand why they went for the silence of hydraulics for the window and seats.

Modern systems can be made to work. I have an old Toyota Landcruiser and the climate control on that is excellent. But it also must cost a fortune to install. I guess you get what you pay for.

Consult the owner's manuals and learn how the controls work. You may be pleasantly surprised.

Look in the glove box for gloves and hat. A 87 degree thermostat?

My W115 has the best ventilation out of the cars I've driven. The center fresh air vent that blows out over the radio is second to none!