New (to me) 1987, w124, 300d - PeachParts Mercedes-Benz Forum

BenzBid · #1 01-05-2012, 03:35 PM

Greetings - proud owner of a 1987 300d turbo. Owned a few w123s and I have to say I am quite impressed! Took her to the local dealer and they did the trap recall and that seems to have improved the non-turbo speed.

Being that I am kind of a newbie with the w124, I have a few questions for those that may have the answers....

Sluggish off the line - I think this has to do with the Alda. I found a how to on here and will give it a shot to see if it helps.

Just did an oil change and was supposed to find what are called "sound encapsulation panels" on the underside of the car. I removed the front one to get to the oil pan. Problem is that the screws that held in in place will no longer thread to the frame. I have it up with some ties, but this is only a temporary solution. Anyone had an experience with this? Better to remove them? I kind of like the idea of an "oil catch".

Heater gets cold at low RPMS - I had a similar problem with a w123 and was able to solve it by replacing the "mono valve". I do not see one on the w124, any suggestions as to what the equivalent is to the mono valve on a w124?

Drivers door lock - looks like the key lock on the drivers door has been jimm'd or something. Is there and easy fix for this, or would a locksmith be a good place to start?

Oil Light - comes on when the car is taking a quick or sharp turn. Just for a moment. Would assume this is just the old moving about in the pan and the sensor is not submerged in the oil for a second. But wanted to see if maybe that is the sign of a bad sensor to come.

Steering - feels a bit tight. Not like any other w123. Tires seem to be ok, but I guess they could be the problem. However, when I got her, the fluid level was low. I drained, replaced the filter and added fresh, but still seems a big tight. Is this the way a w124 rides, or do you think there may be an issue to check out?

Don't have many pics, but here are a few of my phone. Being unloaded and the engine before cleaning.

ashedd · #2 01-05-2012, 05:57 PM

Quote:

Originally Posted by BenzBid

Greetings - proud owner of a 1987 300d turbo. Owned a few w123s and I have to say I am quite impressed! Took her to the local dealer and they did the trap recall and that seems to have improved the non-turbo speed. Congrats

Being that I am kind of a newbie with the w124, I have a few questions for those that may have the answers....

Sluggish off the line - I think this has to do with the Alda. I found a how to on here and will give it a shot to see if it helps. ALDA

Just did an oil change and was supposed to find what are called "sound encapsulation panels" on the underside of the car. I removed the front one to get to the oil pan. Problem is that the screws that held in in place will no longer thread to the frame. I have it up with some ties, but this is only a temporary solution. Anyone had an experience with this? Better to remove them? I kind of like the idea of an "oil catch".

Your lucky to have them. Most do not.

Heater gets cold at low RPMS - I had a similar problem with a w123 and was able to solve it by replacing the "mono valve". I do not see one on the w124, any suggestions as to what the equivalent is to the mono valve on a w124? Aux water pump

Drivers door lock - looks like the key lock on the drivers door has been jimm'd or something. Is there and easy fix for this, or would a locksmith be a good place to start? Dunno

Oil Light - comes on when the car is taking a quick or sharp turn. Just for a moment. Would assume this is just the old moving about in the pan and the sensor is not submerged in the oil for a second. But wanted to see if maybe that is the sign of a bad sensor to come. Mine does the same. I wouldn't worry

Steering - feels a bit tight. Not like any other w123. Tires seem to be ok, but I guess they could be the problem. However, when I got her, the fluid level was low. I drained, replaced the filter and added fresh, but still seems a big tight. Is this the way a w124 rides, or do you think there may be an issue to check out? That's because the 124 is superior to the 123. It should be tight.

Don't have many pics, but here are a few of my phone. Being unloaded and the engine before cleaning.

Watch your engine temp... don't let it get too hot, EVER!

jonbobshinigin · #3 01-05-2012, 06:01 PM

Get that baby on Mobil 1 Synthetic 5w40 Turbo Diesel Truck Oil. It will be much smoother! Also, I have the wagon model of this and I never have the oil light come on during turns.

Did they do the trap recall recently? If so that is still top notch from Mercedes!

sixto · #4 01-06-2012, 01:04 AM

If it's diamond blue with gray leather it's the twin of mine.

Oil light = are you sure the oil level isn't low?

Steering = could be a dragging damper, worn upper strut mounts or worn ball joints. Could also be lots of things in the steering linkage.

Picture = I don't see a transmission amplifier by the glow relay. It's not something to miss if it shifts properly.

Did the car come with service history documentation?

Sixto
87 300D

punkinfair · #5 01-06-2012, 06:42 AM

The sound panels are held to the frame with special screws and little square inserts that snap into holes in the frame. Both are inexpensive and available from the dealer.

Stiff steering on a 124 can be tight balljoints. The test for this is to disconnect tierods and turn the struts by hand. It's a bit subjective as to what is 'too tight' or 'just right'.

I'd be careful about the oil light. Could just be the level sender in the sump acting up but you want to be quite sure about anything relating to low oil level or pressure.

If you have a bad lock cylinder there aren't too many options except ordering new keyed cylinders from the dealer. Installing used replacement parts will use a different key which may be fine for some people but wouldn't be ideal.

shertex · #6 01-06-2012, 07:01 AM

Quote:

Originally Posted by BenzBid

Sluggish off the line - I think this has to do with the Alda. I found a how to on here and will give it a shot to see if it helps.

.......

Heater gets cold at low RPMS - I had a similar problem with a w123 and was able to solve it by replacing the "mono valve". I do not see one on the w124, any suggestions as to what the equivalent is to the mono valve on a w124?

Before messing with the ALDA, make sure you do simple stuff like replace fuel filters.

If heat is weak only at idle, what you need to do is replace the auxiliary water pump. Your car has a movovalve, but that is not the problem.

shertex · #7 01-06-2012, 07:04 AM

On the stiff steering, if the ball joints are original replace them if for no other reason than as a safety precaution....it's just not worth the risk.

BenzBid · #8 01-06-2012, 01:41 PM

Thanks for all the good info! When I got her, I changed all the filters, air, oil, fuel, etc.. Did a diesel purge as well. I'll give the ALDA a shot this weekend and try not to break anything. I'll also check the ball joints.

shertex · #9 01-06-2012, 01:45 PM

Quote:

Originally Posted by BenzBid

Thanks for all the good info! When I got her, I changed all the filters, air, oil, fuel, etc.. Did a diesel purge as well. I'll give the ALDA a shot this weekend and try not to break anything. I'll also check the ball joints.

Something I found out recently: sometimes bad ball joints can be difficult to detect....they can be bad without being loose or creaking.

vstech · #10 01-06-2012, 03:37 PM

Quote:

Originally Posted by shertex

On the stiff steering, if the ball joints are original replace them if for no other reason than as a safety precaution....it's just not worth the risk.

Hmmmm.
I've not heard this recommendation, have you had issues with the ball joints in the 124?

shertex · #11 01-06-2012, 03:48 PM

Quote:

Originally Posted by vstech

Hmmmm.
I've not heard this recommendation, have you had issues with the ball joints in the 124?

Yes. In my case, I had one very competent indie inspect the ball joints on my 91 300D, say they looked fine, only to find out later that they were the cause of my binding steering. More significantly I had a conversation with an indie in PA (when I was trying to figure out my steering issues) who knows the older Benzes INSIDE AND OUT. He relayed an instance where he visually inspected the ball joints on his daughter's car and one of them fell apart that week going down an alley! My point is that, apart from taking apart the suspension components, even a competent, experienced mechanic can miss bad ball joints.

In the OP's case, if he has ball joints that are now 25 years old, I say just go ahead and replace them....it's too significant a safety issue.

vstech · #12 01-06-2012, 03:57 PM

yeah, from a DIY standpoint, I'd agree. or have the suspension opened up, and verify if they are good or not... keep in mind that front 124 ball joints can require entire control arm replacements... the 87 has replaceable ones, but not all 124's joints are...

dagObx · #13 01-06-2012, 09:04 PM

Congrats on your new "rocket ship"!

I have one like yours (green color? Looks like it in the pic). I love mine!

Don't waste time fooling with the ALDA - just take it off & save it for the next owner. If you mind your right foot, it won't cause problems like over smoking. But you won't be able to resist goosing her around a little to feel the extra low-end power.

As was said above, WATCH YOUR ENGINE TEMP!! If you have the "dreaded" #14 head, don't let it throw you for a loop. Mine does & easy to live with if you watch your temps.

The oil level sensor should be replaced. Mine suffered from the same symptoms, light would come on, I'd check oil level only to find it was OK. Replace the sensor & then it will only come on when you REALLY need more oil. My indie said that this was a common failure on the early 124s.

X2 on getting it on synthetic oil. If you ask 10 people on this board what oil to use, you'll get 10 different answers, but the Mobil 1 suggestion above is a good one.

X2 on the auxiliary water pump. It boosts heat output at low RPMS. Yours is probably dead.

X2 on VSTech's advice on ball joints. The 87 model is replaceable. I also concur with the advice of going ahead & replacing both now, rather than waiting for a failure in a far-away location. Mine failed in the grocery store parking lot, which was nice since I had just returned from a 500+ mile trip to the VA hospital. I don't even want to think about what a mess I would be in if it had let go on the road.

Anyways, you have an excellent car on your hands that will provide you with many years of good service (not to mention around 30 mpg hiway mileage). Good luck & have fun!

sixto · #14 01-07-2012, 01:33 AM

FWIW the auxiliary pump is under the windshield washer fluid bottle. It pulls straight up after disconnecting the level sensor and pump motor wires. There's enough slack in the fluid lines to move it aside.

Sixto
87 300D

retmil46 · #15 01-07-2012, 10:22 AM

Quote:

Originally Posted by shertex

Before messing with the ALDA, make sure you do simple stuff like replace fuel filters.

If heat is weak only at idle, what you need to do is replace the auxiliary water pump. Your car has a movovalve, but that is not the problem.

X2 on the ALDA. On my two 87's, both were sluggish when I first got them - and I never had to touch the ALDA on either one to cure the sluggishness and make them live up to their "rocket ship" nickname - matter of fact, on one of them, the ALDA is still "virgin" with the original factory cap.

I just got a copy of the W124 Service Library and started walking thru all the checks and adjustments in the FSM - throttle cable idle and full stop, throttle linkage, tranny feedback cable and vacuum signal, vacuum control valve, vacuum lines, sensor lines, resistor cap idle setting, etc, etc - once all the basics were set back to rights after twenty-some-odd years, there wasn't any need to mess with the ALDA.

Quick check you can do to verify the aux water pump is toast - start the car and let it run until it's at some semblance of full coolant temp. Set the climate control for max heat, blower in auto, and while still idling put it in Defrost mode. If you don't see the coolant temp gauge drop like a rock by at least 5 to 10 C after at least 15 to 20 seconds, the aux water pump has went bye-bye.

Aux water pump is also important from another standpoint - it's nearly effin impossible to get all the air vented from the heater circuit after a coolant change with a nonfunctional AWP.

What's your oil pressure running at cold and hot idle? If I remember correctly, minimum spec per the FSM is around 1 bar at hot idle. Even if it's getting toward the low end at hot idle, as long as it zooms back up as soon as you give it some throttle it's still healthy enough for quite some time to come.