Air cleaner Rattle. It's not the mounts. - PeachParts Mercedes-Benz Forum

JenTay · #1 12-12-2003, 06:19 AM

Guys,
I still need your help on this one. I thought the rubber mounts had failed on my 240. i removed the air cleaner last night and found them still intact.
The tinny rattle is coming from the linkage (all those ball and socket rods) that controls engine speed. it is the same linkage that is attached to the 'stop' engine switch.
I find that the rattle gets worse when i slightly push the 'stop' switch in the direction of stopping the motor.
So i need to adjust the idle slightly up a little. the idle control knob from inside the car is frozen in place right now. any tips? pics with arrows would be helpful. thanks

jen

engatwork · #2 12-12-2003, 06:40 AM

Jen I don't have pics of that particular application but to start I would suggest disassembling the linkages, cleaning the "ball/socket" real well, lube em up and put it all back together. Based on how long it has been since this was done some of them may be a pia to get apart. I use a flat blade screwdriver to pry them apart and I have heard of other people using a 10mm open end wrench. Take your time in getting them apart. As far as lube goes some folks use atf on them and I have seen grease used in other applications. Check out the bushings at all the pivot points.

thebern · #3 12-12-2003, 07:51 AM

Jen Tay, DO NOT remove them all at once, it will be a Rubics cube to reassemble. do one end at a time. It can also be helpful to take a few pictures (digital) as referance to be sure it all gets back together the way it came apart. I use ATF to lube mine.

thebern

JimSmith · #4 12-12-2003, 08:13 AM

JenTay,

The idle adjustment knob on the dash is a fairly important control if you live in a cold area as starting with it in the slow position can be more difficult than it needs to be. And some times you don't get more than a first attempt before your chances at success fade quickly.

Anyway, the idle adjustment knob cable ends at the throttle linkage cluster of mechanical levers, bars, pivots and so on that attaches to the valve cover. If you have cruise control, there may be a cable from that device that attaches to the same stamped sheet metal support. There is an adjustment feature to control the idle speed much like the adjustment feature on a set of caliper brakes on a bicycle where idle adjustment knob cable sheath ends. The cable sheath ends by slipping into a collar threaded into the sheet metal support. The cable itself goes through the collar and is captured by the end of a lever that manipulates the throttle. I am writing this from memory as my daughter has already departed for work in "her" Diesel so bear with me.

If your cable is indeed frozen but still there, you should still be able to use this feature to adjust the idle speed. By unscrewing the collar you will cause the throttle to be moved in the direction of increasing engine speed. I believe there is a small lock nut on the collar threads that you tighten to set the speed so it does not change due to engine vibration.

Be careful to set the low idle speed with the engine warm though as if the engine idle speed is too high, and this cable adjustment mimmics you pressing the pedal down a little, the intake throttle plate for idling can be displaced by the other linkage bars. If you set it up like this, to idle too fast when warm, the idle speed will increase to an alarming level when the car warms up. Also, one of the reasons Diesels are popular for taxis is they can idle without using much fuel. The idle speed is typically so low, and the engine "efficiency" high enough that they cannot even maintain normal engine temperatures. In cold climates you see trucks and cars with Diesel engines that have means to block off the radiator air flow. Anyway, if you adjust the idle speed high and always run it there, you will notice a drop in fuel economy if you drive in the city a lot (obviously this has no effect if you drive mostly on the highway).

While you are in there look to see why your cable to the knob on the dash seems bound up. This is a feature I used every day, all year round, and I would have missed it severely if it failed. I have seen the knob get a little loose, but never frozen. Good luck, Jim

bjcsc · #5 12-12-2003, 08:54 AM

Although cleaning and relubing the linkage joints is good practice and a good place to start, it won't solve your rattle problems. More than likely, some of the lock nuts that lock the ends of the individual rods themselves have come loose, and by vibrating shortened their span. When you clean them up and reinstall them, make sure they are the correct length by making sure they fit tight, but not so tight as to move what they are connected to on their own. Basically you just loosend the locknut and screw the end in or out as needed. Once you get them all set make sure the locknuts are tight. A well adjusted linkage makes a great deal of difference.

bodyart27 · #6 12-12-2003, 10:04 AM

Something I noticed on my 84 300SD was that the air cleaner box (the round metal can that holds the air filter) would actually make contact when the engine was fairly cold at start-up and I placed the car in gear (either reverse or drive). I could even see a slight dent developing as it made contact with that brass looking plate with the four bolts to the top of the valve cover that holds some linkage and vacuum tubes, etc...

So, off came the air assembly and out came the dremel! I ground down the plate slightly in an arc to mirror to curve of the air box.... problem solved!

If I think about it this weekend, I'll post a pic....

JenTay · #7 12-12-2003, 03:44 PM

i may have fixed it. at lunch today i worked on it in the parking lot. it must have looked like a beverly hillbillies scene with the airbox and filter out. anyway. i put it back together then adjusted the idle by tightening a cable which i assume is attached to the nonworking idle adjust screw. we'll see how it goes.

i'm outta here. have a good weekend y'all. you come back now y'hear? as granny would say.

jen

adamb · #8 12-12-2003, 11:01 PM

I have found that using Brake Caliper Grease is very effective on the throttle linkage. I have tried several other things and it seems to lubricate the best and last the longest.
Cya,
Adam

leathermang · #9 12-12-2003, 11:18 PM

Just for the record... the Factory Shop Manual specifically says to ONLY use automatic trans fluid to lub them.... I don't know why.. seems like any 'white grease ' would be fine....

Tirebiter · #10 12-12-2003, 11:30 PM

Jerry Fairchild had the Bosch franchise for gasoline MFI pumps and he taught me to use silicone stop cock grease bought at any scientific supply. It won't melt out or run, it stays put, and water has no affect on it. A $4.00 jar will do 20 sets of our diesel linkage arms. Also works wonders on window channel tracks.
I'm NOT SURE how really cold weather affects it. Winter tempertures here plummet into the 50's

JimSmith · #11 12-13-2003, 09:11 AM

JenTay,

Next time you try twisting the idle speed control knob, do it with the throttle pedal pressed about half way down. This takes the load of having to move all that linkage away, and may make your idle adjustment knob move again. It is lucky for you that you do not live where it gets colder in the winter as without the idle adusted to the high end, I don't think our 240D would start in cold weather. Good luck, Jim

roy wood · #12 12-13-2003, 09:39 AM

on a related note, when i attempted to adjust the connecting rod
that operates the lever for vac. control valve for tranny on the
ip, the manual gave a specific length that the end sockets were
to be from the center of the rod. is there a condensed listing of
the intended lengths of the sockets from the centers of all the
connecting rods in the linkage setup? i take it they're all different based on length --

just wondering.

thanks.

JenTay · #13 12-15-2003, 11:23 AM

Thanks to everyone who offered suggestions on what the problem might be. It turned out to be a cracked exhaust pipe (see thread).

I guess you count me into that "frugal" group.

I initially called midas and they wanted to see the car first and said that it was probably so old and rotten that the whole system might need to be replaced. HA!

I love this forum because it empowers the regular Joe (in my case Jen) to fight the whole "car repair" conspiracy. OR better yet.. the whole "car-replacement-every-4-years" conspiracy.
I truly believe that most domestic cars are designed to fail in one way or another within or about 4 years. This is further reinforced by their low resale value. why bother to 'fix' a cavalier when it is not worth that much? one is then tempted to just get a new cavalier. Then the cycle repeats.

I thumb my nose at Midas and every other ripoff place like that.

Just my $0.03

Jen

suginami · #14 12-15-2003, 07:01 PM

Quote:

Originally posted by JenTay

I truly believe that most domestic cars are designed to fail in one way or another within or about 4 years. This is further reinforced by their low resale value. why bother to 'fix' a cavalier when it is not worth that much? one is then tempted to just get a new cavalier. Then the cycle repeats.

I'm afraid this is true of not only domestic cars, but also of the "new" Mercedes, too.

The precipitous decline in quality occurred in 1996 with the release of the W210 chassis E class cars. Complaints on quality problems on this site have exploded.

It is believed that the last true "keep forever" Mercedes were surely the W123 chassis cars, and possibly the W124's.

driad_98 · #15 03-10-2004, 08:59 PM

My idle control knob is frozen too... not to mention the melted cable housing... anyone ever seen that? I don't know whether to replace the cable, my car starts fine... any reason for it other than starting? Thanks!

Ash