A few questions from a new 300d owner
 

Hi all, I have a few more questions for you if you don't mind. I've got my 83 300d on the road now and love it. This thing goes down the road so solid, it truely is a great ride (my other car is a 98 explorer and the 300d rides much nicer) I do have a few concerns though that I thought you all could help me with.....First at what temp should this thing run at normally? I ran into some major traffic the other day and sat on the highway for an hour and a half to go 7 miles (with the AC on). Then the car sat running for 10 minutes while I made the delivery I was making. When I got back to the car I noticed a little antifreeze on the ground. Not a lot but maybe a cup or two. It looked to be blowing out the overflow hose. The temp was up over 100 degrees C on the gauge. Once I got moving it went back down to around 90 degrees C. Is this normal? A friend who has an older MB told me he doesn't use the air conditioner when he is in traffic for this reason. Should I be allarmed about this or just watch it? Once I got moving I put another 200 miles on the car this weekend with the temp gauge staying between 80 and 100 degrees (pretty much in the middle).

Also what is the meaning of the oil gauge. It is always on 3 when I am moving and drops down a little when I am idleing. Again is this normal? I did not receive a manual with this car so i am not sure what normal would be.

Third stupid question (because I don't have a manual and never owned an MB before). what are the meaning of the 5 buttons for the heater/AC unit? I'm not familliar with some of the pictures on the buttons. I wanted to turn off the AC while it was overheating and couldn't figure it out. I finally pushed the last one to the right and it stopped blowing so I am assuming this is off BUT????

Sorry if these are very basic/stupid questions and thanks in advance for your help.....John

You can find owner's manual information (and much, much, more) at http://skinnerbox.steaky.org.


-- eskimo

john,
your should try to pinpoint the source of the leaking anti-freeze. post back.
i'll let the radiator experts comment further about this.


oil gauge. should peg to 3 when the engine is over 1000rpms and stay there
when you are driving. dropping down to 2 or bit under at idle is normal and ok.
if it drops down when you are driving STOP the CAR!

5 buttons on the ACC unit.from left to right as follows
defrost - default full heat
a/c compressor on - air flow top and bottom vents
a/c compressor on - air flow bottom vents
EC mode - a/c compressor off - (sort of the same as ''vent'' on american cars)
air flow top and bottom
finally last one is off

cabin temperature is controlled by the wheel to the left in Deg C. clicks at either end are full heat and full cool. in between is automatically controlled temperature. small changes of the hweel are preferable.


fan buttons to the right of ACC top = full fan , middle = auto whcih changes fan speed automatically, bottom = off

hope this helps

Check to make sure your electric fan is running in front of the radiator while the ac is on and the car is hot, if it isn't that might be why it's getting a little hot. Anything between 80 and 100 should be ok for a normal temp, it should be safe a lot higher than that but if it stays over 100 then something isn't right.

a little coolant "outflow" under these circumstances seems
 

pretty normal...I'd top up the coolant reservoir with water the next time I came out in the morning before I started up...likely the coolant "loss" won't even be noticed.

Ironic that the times you want to run AC the most are the times it's hardest on the car.

You should be able to find an owner's manual for the W123 diesels at a junkyard, used car lot, or from a mechanic who works on a lot of these cars...I'm amazed at the number of these cars I find junked out but with manuals, operating tags for various controls, and even the booklet on where you could find diesel fuel in 1983 still in the glovebox...ask and you can likely be told just to take it.

a/c mode(s)

Top = defroster vents
middle = center vents
bottom = heater vents (at floor)

From left, 2nd button sends air out top and middle
3rd button is middle only

Right?

ok yes to clarify defrost is top vents and 2 side vents, 2nd button
a/c all vents, 3rd button a/c all middle and bottom vents , and EC bottom and 2 side vents.

i get confused myself because i removed the center vent flap in my car
:eek: :o

Replace the coolant tank cap with a new cap and you should see better temps and no coolant overflow. The system has to pressurize properly to keep the temps down, and it sounds like your cap has gotten too old for the task.

Thanks to all who replied, it was very helpfull. I'll replace the overflow cap as suggested and watch the temp. It only got up to 100 while it sat and came back down once I got the car moving. I'll also check the electric fan. Also thanks for all the help with the buttons, I have them down now. Looks like my oil gauge is working properly as well. :)

Some other observations I have figured out from searching this site:

Looks like my drivers seat has the same problem many others have. The only machanical issues I seem to have left are the antenna mast is shot. This shouldn't be a problem to fix. The passenger rear window doesn't work, and I have no dash lights. I'm not all that concerned about the window since the others as well as the sunroof work fine. Is there anything tricky about the dash bulbs? I've already seen a good post on the antenna.

I really love this car and really appreciate a site like this with so many people who seem to like these cars as well and are willing to help. thanks again, John

Hey, I only learned the correct vent "order" when I finally got a vacuum issue resolved and got full center vent air and a smooth shifting transmission.

Those two things are soooooooooo nice.

smooth shifting transmition ???? OK, I guess I have one other mechanical problem. I do get a jolt after 2k on the tach and then a shift that is a little rough. I'm assuming the first jolt is the turbo kicking in. The shifting is a lttle rough though.... :confused:

Similar shifting "jolts" on many 300s...think its pretty
 

normal.

'85 300D - Drive for 2 years with head snapping back at each shift. Non MB mechanic played with it for years (with my money) trying to find problem. Started going to local (great) indy mechanic who specialized in MB. Found Vacuum leak right away, fixed, car shifted like new. Faster too. Not sure why that was but the car is now peppy. :p

'87 300SDL - Shifts were getting progressively harsher. Also had HVAC issue with vent air. AC came 95% out of the defroster. After researching this site was convinced of vacuum issues. Same indy found a bad connector and replaced it. Smooth shifting and proper hvac for 1 day and then back to same. Took it back and they simply removed a valve or restrictor that they thought was clogged. Shifting smooth and hvac perfect since. No other ill effects. :D

Seems to me 70% of problems with these cars are vacuum related. :confused:

jld,

I don't agree that the radiator cap will help cooling as I leave mine loose all the time and I have no cooling problems. Really all the cap does is raise the boiling point of the coolant by creating pressure in the cooling system.

If your cooling system was overfilled, some coolant would leak out because of expansion, and this is why there is an overflow hose. Next time your engine gets hot, notice if the auxilary fan is running. If it isn't running, getting it fixed will help cool the engine at idling speeds.

You may ask why I leave my radiator cap loose. Its because I use Evans waterless coolant which boils at ~375*F and thus requires no pressure in the cooling system. No pressure means there is much less stress on all the cooling system componants: Radiator, hoses, water pump, heater core, valves and any others parts that have any engine coolant in them.

P E H

Uh oh. I think my shifting could be vacume related. Last night I drove it for a little while in slow moving traffic. Lost power to the brakes. The car stopped but the pedal was dead. It started idling rough as well. I pulled it over and shut it down. Pulled the keys out and everything but it kept on running. I hit the stop button on the engine and it quit. I drove it home a different way where I was able to get up to speed and I got the breake pedal back and it shut down normal. Could this be a small vacume leak????? It started fine and shut down this morning but I did not drive it today for fear of harming it.....Any ideas?