New to the boards. - PeachParts Mercedes-Benz Forum

John-84-300D · #1 11-20-2011, 02:09 AM

As my user name suggests, I've got an old Mercedes Benz 300D sedan. Yeah, the 3.0 Inline 5 TurboDiesel that has almost 230K, I drive her around every few days or so (I have other cars, I tend to swap around), but a couple thousand miles a month on her at most.

For right now, I'm on a shoe-string budget, but I've managed to give her some recent maintenance that has improved her MPG and also some repairs that have improved her driving ability.

1st, I replaced the horribly nasty air filter, both fuel filters, and the oil/oil filter. I used MAAN oil filter from the Mercedes-Benz dealer, the rest I bought new but not German. Trust me, given the choice in what was in there and what I have in there now, it was the right thing to do. I know most of you guys prefer OEM stuff, and I do to, but like I said, budget is an issue.

2nd. I repaired two vaccum lines that were rotted out a bit. This stopped the surging and lack of power I was experiancing. I also lubricated the throttle linkage and this helped a lot with the sticky throttle. In fact, that's why the old woman gave the car up, if she hit the throttle hard enough to get it to go down, the car lurched ahead. It's much smoother to take off in now, and after driving it a few thousand miles, I've learned how to manipulate the transmission into decent shifts and downshifts when I need them.

One problem that has plauged the car for years is that it will not turn off with the key. It will continue to run until it runs out of diesel (unless, of course, you press "STOP" button under the hood, which isn't convinant everytime I want to shut the engine off). Something is not right there, and I was hoping maybe you guys had an idea on what to do about it. I have checked all vaccum hoses I can find, including those that go to that maze of vaccum hoses moutned on top of the valve cover near the throttle linkage, everything seems to be OK, no leaks, no missing hoses. Is there a solenoid that is vaccum controled that I should be looking for? I'd appreciate your help on where to go next for a solution to this problem.

I have further plans for the car, including an entire overhaul of the brakes (whole system), suspension, both rear CV axles and possibly the steering system as well. There are also a lot (or one very large) oil leak(s) coming from the front of the engine. The oil cap itself seems to like to seep oil. I found recipts in the car where the valve cover was repalced, as were all of the seals in the transmission (which was slightly low when I got it).

On the plus side, it runs well, returns MPG in the mid-20s after the filters change, and the heater works great. We'll worry about the A/C system in a few months, as well as the cracked dash and so forth. It's to be a work in progress, fix a few things here and there to make and keep it reliable. It's not a daily driver, but it can be if need be. I would later like to do some updating to the front clip, give it more classy looking Euro-style head lamps, fog lamps and signal lamps to replace the old round (and yellow) ones it has now, which are in moderate to poor condition. The grille is also missing a plastic chrome strip on the bottom left corner and the emblem fell off on the ground one day (was always crooked since I got the car).

Well, I hope I havn't bored you all to death, I'll check back later for any responses. I'm new to German cars and diesels for that matter. We've had a Ford (International) 7.3L PowerStroke in the family since new, now with over 300K miles on it, but that truck has been super reliable, not much of a learning experiance if nothing ever goes wrong, besides, I'm sure this German 5cyl is totally different.

martureo · #2 11-20-2011, 02:22 AM

1) OEM isn't always necessary, but do avoid URO and MEYLE parts as you WILL replace them almost every year. Try to find acceptable alternatives as all of us know that the MBZ parts can be out of range of any budget at times. Febi, Lemforder, ATE etc....

2) The shutoff problem is mostly likely to be a vacuum line leaking. You never said how you checked the lines so I'd advise getting at minimum a set of golf tees and blocking off different systems to narrow down the leak. It could be the shutoff valve itself, but I'd check absolutely everything else before I'd blame that.

Search "vacuum leaks" and you'll get a load of info as they are a VERY common problem.

3)Check out the diy section on this site and learn to use the search function as there are dozens of well done writeups and explanations on almost every repair/upgrade/modification you can think of.

4)If you're planning on doing most of the work yourself I'd get at minimum the Haynes manual or better yet the FSM from the Classic Center in California (it's like $25 for two CDs that have the range of w123 manuals).

5) Go to epc.startekinfo.com put in your credit card info (don't worry it's free) and you now have access to the MB parts catalog (that is if you live in the US). If you need a part you'll be able to get the p/n and the assembly diagrams will help you figure out how stuff is put together.

6) Most importantly! Fill out your signature or profile so people in the future will know what model/year you have and where you are so someone might be able to drop by and help.

John-84-300D · #3 11-20-2011, 02:25 AM

Thanks man, I did mention in my sig what my cars are, including the 300D at the top. I will check out the resources you suggested.

t walgamuth · #4 11-20-2011, 06:09 AM

Welcome John!

Sounds like you are off to a good start!

(What is wrong with Mehl products or ERO)?

vstech · #5 11-20-2011, 08:17 AM

Welcome to the Forum!!!

we'll keep you going, and help you shut down! the MOST likely candidate for non shut off is the door locks. (usually the trunk lock actually) and if you block off the vacuum supply to them, it usually solves the shut off situation, but a good mity-vac is priceless for testing and finding vacuum leaks.

I'd get a mityvac, and pull the brown line from the back of the IP and see if where itconnected to shuts down your car under vacuum.

Quote:

Originally Posted by t walgamuth

(What is wrong with Mehl products or ERO)?

they are CHEAP chinese junk products that fail regularly.

oldsinner111 · #6 11-20-2011, 08:25 AM

every Purolator or STP oil filter has Mahn stamped on them.

Yak · #7 11-20-2011, 04:57 PM

Rough info on vacuum lines: yellow w/ or w/o stripe = central locking, to include the trunk and the fuel filler flap and the "egg-crate" vacuum reservoir under the shelf in the trunk

Green (or blue green) = climate control
Gray or gray white = engine controls

Brown and brown/purple = shut off. This should tap off the accessory line, go into the firewall to the ignition switch, then back out and down to the modulator near the oil filter housing. If either the locks or the climate control systems have leaks, then the the engine may not shut off properly.

Blue (is probably coupe only) for seat backs.

Tracing vacuum leaks and finding info seems to be hit/miss, partly due to the fact that there are multiple systems involved (brakes, tranny, EGR, A/C, central locks). I'm proud of my thread: Definitive '83 Fed 300CD vacuum thread

Oil leaks aren't unusual. Leaking near the front is frequently the oil lines seeping oil. A straightforward repair as long as the oil cooler nipples don't get damaged -- but not exactly easy and should be planned out ahead of time. Otherwise look at the oil pan, plug and gasket. DO NOT try to remove the allen heads on the pan without a thorough cleaning first. You'll probably strip at least one.

A good engine clean prior to launching into isolating and fixing oil and P/S fluid and tranny fluid leaks is a good idea.

And, the most common advice: adjust the valves.

John-84-300D · #8 11-20-2011, 08:03 PM

Wow, lots of info, guys. Thanks for your help. I had no idea that the central locking could be at fault.

Here's what I have to do to lock my car. I first must get out and shut all doors and lock the drivers door with the key from the outside. This does nothing but lock the driver's door. I then must go around starting with the rear door on that side and lock everything manually. If I do not start properly with the key in the driver's door, it won't let me push the locks down. Somebody at some point (this lady had kids) decided they would force the one down on the passenger side front, and so it is lost behind the door pannel. I have not taken off the door pannel to investigate, I just lock that door with the key from the out side.

Ok, shopping trip over, I come back to unlock my car. I do so by unlocking the driver's door with the key and magicly, the rest of the doors unlock themselves. I assumed the gas flap and trunk lock had little or nothing to do with this issue, I lock the trunk with the key if needed and didn't know the gas flap could be locked (no key hole, it just flaps open if you push in).

Next on the list, I have no dash lights. Rather, I have them but they are very reluctant to come on. Is this in the headlight switch (as it usually is with the Fords)? I have seen my dash lights once or twice, and while not bright, they'd be a welcomed addition to these dark winter nights. They were on for an instant, they were green, everything lit up, then it was gone. Nothing I do with the key, headlamp switch, or buttons on the dash will bring them back. The only thing that lights up at night is the rear defogger switch if it's on, the radio (which does not otherwise work) and the rear dome lamp if I turn it on with the switch on the dash.

My front dome lamp does not work, either, have not investigated that. Possibly the bulb is to blame there.

Tell me where to begin.

I have a feeling I'm going to get lost very quickly, bit I hope not. I have just barely began to take on major repairs to my Fords, and this Mercedes is infinantly more complicated as you can guess. My progress is limited not only by my budget but by my bad back as well (i am disabled which explains the limited budget, too).

Thanks so much for your help.

tangofox007 · #9 11-20-2011, 08:07 PM

Quote:

Originally Posted by oldsinner111

every Purolator or STP oil filter has Mahn stamped on them.

Such is not the case.

John-84-300D · #10 11-20-2011, 08:09 PM

Quote:

Originally Posted by oldsinner111

every Purolator or STP oil filter has Mahn stamped on them.

I use Motorcraft or AC Delco on anything else I own, not suprisingly, they dont make much for a diesel Mercedes. I've been going with what Autozone can get for me as far as the fuel filters and air filter, I did go to the Mercedes-Benz dealer for an OEM oil filter. It was expensive and about 70 miles away from my house, lol, not looking forward to that everytime I need an oil change, but I don't know any other local places to get decent parts. The dealer acted as though I was getting the last of the last OEM oil filters, it was in a very dusty box with writing on it from the mid 1990s. He said he doubted that they'd send him another one when that one turned up sold.

I swear, this car needs a lot more than my 1993 Ford Taurus did at this mileage, and everything is very much more expensive and hard to come by. I am not complaining, just stating a fact. I got 300,000 out of the Taurus before I sold it, guy said he got another year or so out of it before the trans finnaly went and he junked it.

I don't plan on getting rid of the Mercedes, ever. It was a gift from a family member and I love old cars anyway so it's not like I plan to flip it and resell it.

newtodiesel · #11 11-20-2011, 08:19 PM

One area to investigate. Upon buying a new to you mercedes, change out all the old fuses under the hood with copper fuses. You can get them on ebay or your local imports store or buy them from this forum, which we like to support since they sponsor our forum. The original fuses are a silver kinda color and most are so corroded you cant tell if they are working or not. Best thing to do is change out ALL of them. I think BMW and VW used the same fuses, so if you can find an old vw parts seller they will more than likely be the same kind of fuse you need. Here is a link to our sponsor. Look up top under buy parts tab. Remeber to replace them one by one so you dont forget where they all go!!

PeachParts FastLane Mercedes Parts Store

Here is another link too!

MERCEDES BEST upgrade fuses 300SEL 3.5 4.5 6.3 280SEl | eBay

Skippy · #12 11-20-2011, 08:26 PM

Dash lights: Easy fix. Most likely the rheostat behind the dash light brightness adjustment (little black knob on the left side of the bottom of the gauge cluster has gone bad. You can buy an expensive replacement from the dealer, or you can do what most of us have done and just solder a jumper wire across the terminals. You did say that when they came on that one time they were green. They are white from the factory, so yours have been messed with in some way.

Oil filters: I bought one today from NAPA for twelve bucks. They had it in stock, along with the inline fuel filter I bought. I've also bought filters from this site. I try to avoid ever buying anything from Autozone.

Vacuum system: Follow the link in post #7, buy a handheld vacuum pump with gauge from Harbor Freight for ten bucks, and start troubleshooting. Not really hard, but time consuming and sometimes frustrating.

Maybe it's a regional thing, but I find parts availability and pricing for my '83 Mercedes is slightly better than for the '86 Lincoln it replaced. Even the '71 is relatively easy to get parts for if I don't mind waiting.

John-84-300D · #13 11-20-2011, 09:18 PM

Quote:

Originally Posted by Skippy

Dash lights: Easy fix. Most likely the rheostat behind the dash light brightness adjustment (little black knob on the left side of the bottom of the gauge cluster .

I cannot find such a switch. I find the brake release, the headlamp switch and the only two little black knobs on the gauge cluster are for the indash clock adjustment (RH one) and the trip odometer reset (LH one). They don't seem to do anything else. I can't find any other switch or knob.

I figured that they had to have put one somewhere, but I have never been able to find it (a brightness adjustment knob).

vstech · #14 11-20-2011, 09:22 PM

Quote:

Originally Posted by John-84-300D

I cannot find such a switch. I find the brake release, the headlamp switch and the only two little black knobs on the gauge cluster are for the indash clock adjustment (RH one) and the trip odometer reset (LH one). They don't seem to do anything else. I can't find any other switch or knob.

I figured that they had to have put one somewhere, but I have never been able to find it (a brightness adjustment knob).

it's the left knob. the one for trip odometer reset. push to reset the odo, turn to adjust the brightness of the cluster lights.
however, MOST reostats do not work, and need repair or bypass

it's the left knob. the one for trip odometer reset. push to reset the odo, turn to adjust the brightness of the cluster lights.
however, MOST reostats do not work, and need repair or bypass

Skippy · #15 11-20-2011, 09:22 PM

The trip odometer reset is also the brightness control. Try turning it back and forth to see if your dash lights come back on. Sometimes this little trick will get them to work again for a little while.