Couple of questions for you SDL owners - PeachParts Mercedes-Benz Forum

Ether · #1 04-05-2009, 07:20 PM

Under the hood, drivers side near the firewall, there is a dial type gizmo that is numbered 1-9 I think. Looks like it can be rotated for different settings. What is it? What does it do?

What is your typical tach rpm at 70 MPH?

JackG · #2 04-05-2009, 07:23 PM

Quote:

Originally Posted by Ether

Under the hood, drivers side near the firewall, there is a dial type gizmo that is numbered 1-9 I think. What does it do?

It is there to tell the cat you just ran over, how many lives it has left

.

just kidding, I haven't a clue

bustedbenz · #3 04-05-2009, 07:32 PM

Quote:

Originally Posted by Ether

Under the hood, drivers side near the firewall, there is a dial type gizmo that is numbered 1-9 I think. Looks like it can be rotated for different settings. What is it? What does it do?

What is your typical tach rpm at 70 MPH?

It's an idle speed adjuster. 20 rpm +/- for each number up for down from the default position, which is 4. Recommended idle is 630rpm +/-20 @ position 4.

Mine runs at least 3k at 70. Maybe 3200ish? I haven't looked that close but I'm used to cruising between 3k and 4k. Sometimes the high side of that if it's an open road.

Ether · #4 04-05-2009, 07:53 PM

Thanks bustedbenz.

I was driving an SDL today and I noted that while the rpm was lower at a given speed than my SD, I had expected it to be even lower. I had no reason to expect that but I guess it was just my preconception. It was just at or under 3k at 70 mph (checked with gps) so that must be about right.

LUVMBDiesels · #5 04-05-2009, 09:07 PM

My '86 runs about 3400 RPM at 80MPH..It is just around or under 3000 at 70.

My idle is set at '7' and is too high. I will be setting it down to '4' now that it is warmer...

Ether · #6 04-05-2009, 09:29 PM

Do any of you guys have noisy lifters? One particular SDL that I'm looking at has a tic, tic, tic, tic noise that varies with engine speed?

I recall having a similar noise with a 2.5 liter 300D I used to own.

sixto · #7 04-05-2009, 11:07 PM

Not uncommon. Sometimes 20-30K miles on Mobil or Delvac synthetic will clear the noise but then you're hooked. Worst case is the head gasket is disintegrating in the usual spot near the #1 exhaust runner sending debris into the oil passages to the lifters. Less severe but time consuming is finding and replacing the lifter that's gone soft.

I wouldn't pass on a car with lifter tick at idle.

Sixto
87 300D

LUVMBDiesels · #8 04-06-2009, 04:59 AM

At 300000 miles mine developed an occasional lifter tick. Switching to M1 from Rotella T cured it in a couple thousand miles. This car had been run on dino oil for its entire life. The Rotella synthetic and the M1 really cleaned it up inside to the point where there is no sludge visible when you open the filler cap. I would also not run away froma car with a lifter tick...

Oracle12345 · #9 04-06-2009, 09:13 AM

regarding the noisy lifters, the remedy for the problem is to install the improved valve tappets, a TSB on this issue for the 603 engine.

It is caused by the valve tappets draining oil partially. I know mine were replaced at the dealer since the car was dealershiped its whole life.

replacing the headgasket will not solve your problem and changing what oil you use is only a temporary fix since it will be back.

part number 601 050 04 25(check epc it may have changed)

Ether · #10 04-06-2009, 11:12 AM

Thanks for all the good info guys. Nothing to scare me away from the car I'm considering.

The valve tappet replacement doesn't sound like an easy DYI though.

mplafleur · #11 04-06-2009, 12:28 PM

Quote:

Originally Posted by Ether

What is your typical tach rpm at 70 MPH?

I don't know. I've owned mine for 6 years and haven't have it over 20 mph.

Ether · #12 04-08-2009, 09:56 PM

Ok, now that I own one I need to ask another question.

Is there anything different about the brake bleeding process with ABS? Can I just connect my pressure bleeder to the MC reservoir and go at it?

daw_two · #13 04-08-2009, 11:11 PM

Quote:

Originally Posted by Ether

Ok, now that I own one I need to ask another question.

Is there anything different about the brake bleeding process with ABS? Can I just connect my pressure bleeder to the MC reservoir and go at it?

Don't forget to "flush" the brake fluid system. Which means you got to open the little things at each wheel. Be careful with them. They have been known to be stubborn and at least one forum member has broken one.