Mercedes 300D Suggestions

Mr_Shiftright

Just unscrew them like a spark plug, one at a time...you need a deep socket...it's really easy.

opsterusa

No, The car rides very nice, corners great. The tranmission shifts so smooth you can't feel it go through the gears. We are going to replace the mounts that hold the rear end to the body. As far as we can tell thats all that is left. My mechanic says no, but I suspect a tranmission problem. I will keep the forum up to date.

Thanks

Mr_Shiftright

The transmission is SMOOTH? Now that's a first. :P

I don't think it has anything to do with the transmission either.

wyte

Where can I find optimum operating data based on "as new" condition such as 0-60 acceleration, turbo boost pressures, rpm's at at road condition speeds, transmission shift points under full accelleration, passing gear speeds, ideal oil pressure at given rpm's, engine temperatures, etc., I have haynes repair manual but that just gives vanilla specs. Seeking "under ideal conditions" "as if new" type data.

Mr_Shiftright

Everybody who owns a 300 series diesel and who works on their own car has to have the three-volume workshop manual. For those kinds of stats, you *might* be able to find some of that in the booklet packet that they originally issued with the car from the factory...this had owner's manual, maintenance book and I think a spec book. Try eBay for that or the dealer.

ryan66

I have a 1982 300D Turbo. Just changed the fuel filters. How long should they last with normal driving?

Mr_Shiftright

I used to swap the little plastic ones every 5,000 and the big one every 15,000.

aznoutlawz02

I have a 1987 300D turbo, and being the typical high school student that I am, I'm not satisfied with the acceleration of the car. Everything else about it is great, I have had to replace a few parts here and there but I'm happy since I bought the car from one of my dads friends at $1000 @ 170k miles. And the interior was in good condition.

However, the only problem with the car is the acceleration, which takes forever until the turbo kicks in, and after that, the car is a powerhorse. I read on one of the earlier posts that this specific model has a "trap oxidizer" which causes problems. I was wondering if this, and any other factors, could be replaced/fixed/taken out in order to have maximum performance. Is there any parts I can add (such as chips, larger turbos, etc.) which I could add on? If so, where could I buy these products. I have heard of some people swapping in the huge semi-truck turbos into the 300D and also getting boost controllers for the car, but I wasn't sure if this was true/possible.

If anyone could help me out, that'd be great. Thanks!

Mr_Shiftright

Yeah if you have a trap oxidizer you might want to have that checked, definitely. It was a problem. It is a cannister upstream of the turbo. If it clogs it kills performance and, some say, particles trapped in the ceramic will break loose and cause engine wear. You can put in a new one but you will have the problem again and again over time. It was just a lousy idea.

Otherwise there's not much you can do with increasing performance. It is what it is.

In this case, if you want a faster car, go buy a faster car. Bigger turbos and boost controllers are basically a formula for building large German hand grenades.

You have 148 HP pushing 3400 lbs. for a 1:22 power to weight ratio. That's the reality of it.

In terms of acceleration specs, your car should do 0-62 mph in about 14 seconds. If you want to take a stopwatch and time this on a highway on-ramp, this will tell you roughly if your car is performing as specified.

Cars with trap oxidizers include 1985 300D, 300CD, 300TD and 300SD in California versions, sold in 11 western states; the 1986 300SDL California version and the 1987 300D, 300TD and 300SDL in both federal and calif. versions.

Generaly I tell people to avoid these cars if possible or buy them cheap like you did.

pkmaven

The reason your 124.133 accelerates slowly from the start is because it starts in second gear not first! All 124 body Mercedes were designed that way. There are no chips or other modifications that will speed this car up, but it also rewards the driver with huge miles per gallon, something to think about these days. It is a VERY safe car which will save your life if someone plows into you. This car was a steal at $1000 with only 177k, as most of these cars will reach 400k miles. Never use green antifreeze, and change the oil every 5k miles. Lubricate the sunroof annually. When it's time to change the front rotors and pads, use "Zimmermann" cross-drilled rotors and "Rotex Gold" brake pads and you will no longer have black front wheels. You can source any part discounted online by using Google to source anything. Shop around the net for the best price. This car was only imported one year, 1987, on the 100th anniversary of Daimler Benz. It was very carefully engineered. It is unlikely that you car still has the trap oxidizer which was recalled by Mercedes and replaced with a newer system which provides more power. If you look left when standing in front of the engine compartment, if you see a large, black plastic cylinder on the left side, that is a trap oxidizer. If you had it you could go to any Mercedes dealer and they would replace a bunch of stuff including the exhaust system for free. Ask your Dad's friend if he answered the recall, and had this modification done. To help the car run better, shift better, etc., order a rubber "F" fitting (part #601-078-06-45), where the vacuum tube comes off the vacuum pump on the front of the engine, there is a rubber "H" fitting with four white tube connected. Delete the left two and plug the right two into the "F" fitting.This easy modification will hugely increase the vacuum to the tranny and the whole car. Forget changing any part of the turbo system and the engine, all designed by Mercedes to last a very long time. To make the car handle much better, replace the rear, top "strut' link in the five arm, multi-link rear suspension. It is probably shot by now and it has been upgraded to a much more heavy-duty part. The difference will be realized as soon as you take the first turn around a corner! Increase the psi of the tires to 35 all around. Replacing the front and rear sway bars with the much thicker ones from the Sport package makes a huge difference, just like rpacing the junk struts and shocks with new Bilsteins. Someone, maybe not you, will eventually rescue this excellent car. P.

Mr_Shiftright

Oh those great suggestions reminded me...I was also going to suggest two other things:

1. You could shift the car manually through the gears starting in lowest gear and this will improve acceleration somewhat. I used to do this all the time and got pretty good at anticipating when I needed the extra power, by manual upshifts (on freeway on ramps), and manual downshifts (rather than waiting for that pokey transmission to do anything).

2. You might want to wait a while before sinking any money into this car. See how it performs for a few months. At 170K it could be pretty tired if it hasn't had regular repairs and maintenance, and any major component failures would cost you much more than the car is worth. Maybe have a Benz tech do a diagnostic on the whole car and write up what's substandard. Then you have a better picture of what's down the road for you.

But if the car turns out to be reliable and gets a good report from the doctor, and you can square away the trap oxidizer issue perhaps with the mods suggested, I'd just drive it and maintain it carefully if I were you, and definitely not mess with engine modifications. Pay particular attention to clean fuel and frequent oil changes.

However, it will never be an exciting car. You have to either give up excitement and mellow out and just enjoy the gentle drumming of that diesel engine down the highway, or you'll have to buy something more powerful.

As for economy, that advantage of the 300D has been compromised by the rise in diesel prices unfortunately, but you should be able to pull 24-26 mpg on the highway, which isn't bad for a big car like that regardless of the price of fuel.

Probably the main advantages of this car for you are safety and reliability and a certain kind of prestige, and the disadvantages are price of fuel, lackluster low end performance and expensive repairs if needed.

Might be a good car for you as it will force you to slow down. I'd say with luck you have another 100K left in that car if you keep it up nicely.

frankiii

i just got a 1982 300D tubo
everything going to the fuse 12 dosent work (turn signals, cluster lights, cruise control, tack) but the stop lamps do work any ideas on why
and also i have a couple leaks transmission fluid, diesel fuel, and oil any common leak areas?
thanks

mercerza

How do you get the starter out, there is barely any room in there, and where is the starter relay?

Mr_Shiftright

Arggh, I wish I hadn't sold my 3 volume shop manual set. I could help you guys out more. I never did a 300D starter.

You might google "Benzworld" for that and then go there and see what's up for info.

Mr_Shiftright

Well do you have a test light? Test current traveling THROUGH # 12 fuse....do you get a light on either end of the fuse? Sometimes those pointy little fuses look good but don't make good contact.

For oil leaks, you can replace the rubber gasket in your oil filler cap. Trans. leaks could be anything so you'd have to get under there, clean it off and see what's what. Diesel fuel leaks are usually loose connection issues or injector seals.

jerry_300d

I am using biodiesel and the fuel lines are starting to weep. I need to replace them. First question: What size ID do I need? Can I use Gates 30R9 fuel injection line or should I buy Viton?

Thanks,

pkmaven

My 124.133 has 250k miles on it and runs perfectly. I easily get over 30mpg, and on the highway I get 33+mpg. I have no leaks. I bought it in 1992 and it still had the trap oxidizer in it. The dealer replaced everything from the header back on the recall. Three years ago I had a cylinder gasket leak and replaced the gasket after noting that the head had no cracks. I removed the egr and bolted on a block-off plate. The tranny shifts smoothly. I only use MB antifreeze. MB US told me I can expect 400k miles from my car and that he (head tech) had the same car with 287k miles on it and that the two techs under him also had this car and they both had over 385k miles on their cars. P.

Mr_Shiftright

Well if you keep replacing stuff as needed you can go as far as you can afford. I think though that natural life without intervention is not going to be 400K. I've never seen any car with 400K myself, restored or not. I think that is very unrealistic but not impossible. It would be like living to the age of 105. It happens but not very often and don't count on it.

Fuel consumption for a W124 is better than for a W123. With an automatic, Benz measures highway mileage of a W124 at 29 mpg at 74 mph, so your mileage is plausible if you drive slower than that on the highway. City/hwy mileage should be about 26 though for the average owner, which is what I was estimating based on factory numbers.

Enough money could drive a Hyundai to one million miles, but one has to say sooner or later what is the point?

Nice thing about a Benz though is that unlike many cars of that 80s era, the Benz build quality is so good that it won't fall apart before the engine does.

ryan66

I have '82 300D. It has an electric plug up front. Does this warm glow plugs or
is it a block heater? ( or both ??? ) Thanks.

Mr_Shiftright

Oh must be block heater. Diesels are hard starting in very cold weather.

You should be able to trace the plug wire back to some kind of cylinder that has water hoses coming out of it.

tech6

I have a 85’ 300 series turbo diesel. When I start it the starter seems to stay engaged momentarily so that I can hear it grind. Does it cold or hot. Is it the starter solenoid and is there a fix short of replacement. How hard is it to replace the solenoid/starter on this car? I just got it.

Thanks

gabsta

I have a 1985 300D, I love this car since I married the owner.

Can anyone tell me if it qualifies for the recall?

At the drivers' feet, thare is a pool of oil, Where did that come from?

Thanks

gabsta

1985 300D, The lights work but not the emergency or indicator signal lights.

Anyone?

Mr_Shiftright

There won't be any recall on a car that old but yet your car might have a trap oxidizer on it.

Pool of oil at driver's feet sounds like a leaky oil filter as one possibility.

rossott

I have a '85 300TD and when the accelerator is in a certain spot I hear a VERY loud squeal from under the hood. Is this a turbo waste gate problem? Thanks.

rossott

Can you just remove the trap oxidizer?

Mr_Shiftright

I'm not sure. I think so. If you use the "Search This Discussion" feature which appears above and below on each page, and type in "trap oxidizer" you will find at least one reference about removing this---one of our members apparently did this successfully. However, as it is part of smog equipment, some shops may refuse to do this for you. Personally I have no knowledge of the consequences to the running of the engine either.

tradedog

Could anybody tell me whether the hood (bonnet) on the later (93, 94) 124 or E class cars will fit on an earlier 124 series Benz? This later hood has a body coloured strip down each side of the grill.

Many Thx

nrkmann

MB was so far ahead with this. A particulate filter that stops carcinogens from going into the atmosphere and our lungs. Many of the European diesel manufacturers have picked up on this.

We should support this technology, not try and go around it. It does work.

exlawyer

I had a car like this, a 300TD wagon. One day I was taking the dash off (not the whole thing) to replace one of the instruments. While I had it off my wife told me to go pick up one of the kids. I just started the car and went to go. I soon found oil on my pants and jacket. It turns out that the oil pressure gauge works directly with the oil, and in fact the oil from the engine runs right up to the back of the instrument panel to indicate pressure. For your situation, I would guess that the connection to the back of the instrument panel is loose. I can think of no other way that oil could get into the passenger compartment of the car.

burdawg

That's a true oil pressure gauge, which has a small capillary tube that connects to a point on the engine where the oil is under pressure.

brasamer

I can't say what causes it, but I have a similar problem with my '82 300TD. My friend said that it sounded like it might be a belt issue. After the car has been running for a while, whenever I'm not cruising/coasting and depress the gas pedal, it makes a tweeting/squealing sound. My sister said it sounded like rats were fighting in the engine. It can get quite loud, but with the stereo on at low volume, you can't hear it from inside the car. With the window down and the radio off though, it can get kind of irritating. Anyone know what is causing this?

Mr_Shiftright

Oh I'm all for the technology or for anything that cuts emissions...but in this case Mercedes engineering for the trap oxidizer wasn't so good--in fact, really BAD. I never remove emissions equipment except for testing....if the trap oxidizer is removed and the car runs great, well there you go, you know the issue.

Mr_Shiftright

sometimes the AC clutch sounds just like that as it starts to wear out.

raidking

It is most likely your fan belt slipping.

300cdveggie

Is there any reason that a vacum should be created in the tank of my 300TDT? I always though that a diesel tank had to be vented. When I went to fill the tank the other day, it was pretty apparant that there was a vacum created. ???

raidking

Check your fuel cap vent hole. If it forms too much vacuum the fuel tank may collapse.

mwufle

I am unable to turn the key in the ignition at all. Jiggling the steering wheel to release the lock doesn't work. Can the ignition switch itself lock up or is there a safety mechanism associated with the steering column? Thanks.

nyulaw

My 1982 300D TD has been giving me good vibes ever since I bought it! (257,000 miles and still solid!) Recently however, it has been vibrating violently when the car is in park, reverse, or whenever im not pressing the pedal. It tends to vibrate harshly on morning startup, then it sort of settles down after a lot of driving?

I think it might be the mounts. Is this expensive to fix? Is it also possible that it is cheap diesel fuel, and should I stick to fuel with high cetane levels?

300cdveggie

I had a similar issue with a '77 300D. Take a look at the motor mounts. You'll be able to tell if they are worn out. If they are, you should have them replaced. If you have a mechanic who charges fair rates, it won't be very expensive.

tech6

ANYONE KNOW WHERE I CAN GET AN AFTER MARKET FUEL TANK FOR A 1985 300 TUBO DIESEL?

TECH6

Mr_Shiftright

Why aftermarket? Is the one from Benz too expensive, or ???

tech6

Actually, I just assumed that the one from Benz would be more expensive. I found it interesting that no one sells after market fuel tanks for this car.

This all started when a friend, who borrowed the car, found a fuel leak under the rear. I havn't had a chance to get to it to see what exactly is leaking. I just started checking on fuel tanks, just in case.

Mr_Shiftright

Well you can also have yours repaired if it is cracked, or you can get one out of the wrecking yard and have it cleaned and tested by a radiator shop and then just do a swap.

burdawg

I doubt if the tank is leaking. More than likely it's a cracked hose or some fitting. The only way to know for sure is to of course crawl up under there and have a look.

tech6

YOUR RIGHT, IT'S NOT THE TANK. I FINALLY GOT UNDER IT AND HAD A LOOK (WITH A FLASH LIGHT ONLY) AND IT LOOKS LIKE ONE OF THE LINES HAS RUSTED THROUGH. I'LL KEEP YOU POSTED.

THANKS FOR THE SUGGESTIONS.

mizzmugg

I am having the exact same problem as mwufle in #850. Can anyone help us with this issue?

jerry_300d

I bought this car used with 97,000 miles. After 6,000 miles the glow plug lights would not come on with the ignition but come on after I was able to start the car. I had the glow plugs replaced and this fixed the problem. 7,000 miles later the same condition. This time I had the glow plugs, the temperature sensor and the relay replaced. 6,000 miles later the same problem.

I was running the car on B100, homebrew biodiesel until 3 weeks ago. I am now blending 50% diesel and 50% biodiesel.

What's happening? What else should I replace? Could the biodiesel be causing this? Are there different brands of glow plugs that might be best suited for biodiesel?

Mr_Shiftright

The only thing I can think of is that the new relay is defective or the wrong one. Usually glow plugs burn out prematurely because the relay is sticking.

Can you time how long they stay on? Should be about 30 seconds MAX I think if you leave the key on...if they don't shut off in 30 seconds, there's your problem. You should be able to hear the relay click off.

brakeengr

In my 1982 300D, I can shift from Park to R, N, or D even if the ignition is not turned on. If it's the same in yours, you could try shifting to Neutral, pushing the car a little forward or back, and see if that releases the ignition? Good luck. I think I had done that some time back when I couldn't turn the key- but cannot remember for sure.