I just inherited (parents extra car) an 86 300E and am having two problems.<br> 1) It is idling very low about 600 rpm by the tach and is very rough at that idle at any other RPM runs great, is this something that I may adjust or is it a problem that a MB mechanic must adjust?<br> 2) I just replaced the A/C compressor and dryer and living in S. Florida cold air is a requirement, the air is cold but when you select the normal cold A/C setting the air doesn't come out of the center vent for a couple of minutes, but the other problem is it always blows cold air out of the top dash vent on the window, which per the owners manual is only operating in the multi level mode (both white arrows) and heating. Has any one else had this problem, or experience fixing it? Any help is greatly appreciated.<br> One last question, I haven't been able to find any repair manuals other than the MB repair CD, is it worth the expense?<br> Thanks Ron<br>
You will get a number of responses with a number of possible corrections to the idle problem. Most commonly mentioned is the OVP that I hope someone will clarify in a follow-up. I also have an 86 300E (68k miles) and have been looking for solutions to my rough idle problem which may be related to a plug that I can hear is not firing. I'm amazed that a somewhat disabled car like this can run so smoothly at 70mph. My AC (climate control) works great. I keep it on medium most of the time. I didn't notice if it was blowing cold on the windscreen but I do know the defroster kicks in immediately and there is a short wait for the AC to kick in. Mine modulates to temperature changes just fine. I don't know about the CD, I am a Mac user. I have the Owners Workshop Manual (Technibooks) that has a lot of valuable information, but I am far from ready to pick up wrench. Let me know if you want a list of other web sources for info.
1- don't know, sorry<br> <br> 2- You defintely have a problem. It could be the pushbutton unit, but it's more likely to be one or more failed vacuum actuators for the flaps in the system. To test them, remove the glovebox, and apply vacuum to each of the 7 vacuum lines at the manifold behind it (left side). All 7 should hold vacuum. If not, you need to replace that pod. Only the floor flap, and defrost flap, can be changed easily. The other 4 require dash removal (4-6 hours). If you have to pull the dash, replace ALL of them! They're $15-$25 each.<br> <br> 3- The factory MB manual is better than anything else out there but assumes you have basic mechanical knowledge. It is just PDF's of the old paper manuals, which are no longer printed. You can get it new from the dealer for $120+, from Rusty (800-741-5252) for under $100, or bootleg copies (CD-R) on eBay for ~$25.<br> <br> <br> HTH,<br> <br> Dave M. :)
I had an evaporator core replaced in my 1987 300E last summer. Afterward I noticed a problem with the dash AC control panel. When you pushed the off button it would not engage fully, it felt as if the button had an obstruction. The AC quit cooling after 3 weeks. The mechanic said he soldered a wire in the dash AC control panel. Again 2 weeks later the AC wouldn't cool. Now he has replaced the dash AC control panel and 2 weeks later again the AC will not cool. Fan blows okay.
1. You can try adjusting the throttle linkage, it is under the air filter housing. Just turn the knob for more or less throttle, but be careful there is also a switch that needs to engage when the car is in P or N.<br> 2. Mine did something similar, it would vent funny in normal mode (clear/white), then I would switch to multi (white/white) for a few minutes, then switch back to normal (clear/white). Then it would be venting fine.... weird but it worked.<br> 3. No idea about the CD. Would like to know though...
Cheery, What happens if that switch is not engaged when in P or N? I have a 88 300CE...I just increased the idle speed, but didn't check to see if the switch was being contacted.
I had the same problem with my 90 300E, and solve it very easily.<br> First you have to check if the vacuum diafragm is working: remove the glove compartment lining.You'll find the diafragm behind it. It's a cilindrical item usually with a plastic pink disc attached to a flat rod and a vacuum line to the other end. Turn your car and a/c on, watching the rod to see if there's movement (slowly in) when you turn the a/c off it should again move out, slowly though. If it does that, then your difragm is good but probably could not be working all the way. Bent the flat rod a litle, to shorten the working distance. With that the windshield flap will travel more and close well.<br> I did that on mine 2 years ago and is still working great. Hope is not late and you had to change it or take your dash down.
Linear Mode
