Mercedes 300D Suggestions

Mr_Shiftright

You might check to see when the last time the engine had a valve adjustment.

Other than that, the secret to diesels is clean fuel, clean injectors, clean filters and keep them at 75 mph or under.

ryan77300d

I have a '77 300D, and have grown to like the car in general, however, there are plenty of things that irritate me about it.

It's got 124,000miles on it, and I'm planning on cutting out the rear suspension points/floor pan, both side trunk sections, the spare tire well, and the drivers foot well and welding in new panels. As the car needs a new head gasket, I'm also planning on pulling the head, changing the timing chain, valve seals, injectors and gasket itself. Assume all the steering/suspension components are also renewed.

After replacing the front seats (I've found excellent cheap spares) and getting the entire car rust, ding and dent free, then repainting it, I was toying with the idea of putting a turbo/intake/exhaust on it. I'm not talking boy-racer crap, but quality parts that will at least give me the driveablility of 20 more hp. Then, to top it all off, I'd like to change the transmission to a standard from a 240D/300D and perhaps put in taller gears to get more highway use out of it.

Does this sound crazy to anyone? Can this engine handle the stresses of a mild turbo, or should I replace it as well? (Have a turbo spare at hand) Would the upgrades be worth it (not in monetary value, I'm past that, I know I'm never getting a cent more than half of what I paid for it) in terms of decent performance? If putting a stick in it isn't feasable, is there any way to modify the transmission so it uses first gear all the time? Would one want it to?

-Ryan

goldcar

I have a 1982 300D turbo. I want to transport two dressers from San Diego up I-5 to San Francisco. I am wondering if I can rent a trailer, hook it up to the car and haul the dressers up I-5.

There is really only one serious grade up I-5, and that is leaving LA.

ryan77300d

With a turbo, you should be fine. I'd prepare for the right lane and flashers up any extreme grades, but those cars are rated to tow 3000lbs or somewhere in that vicinity, albeit very slowly.

First gear would probably help alot to get it off the mark.

Mr_Shiftright

You'll be okay but just DON'T STOP when pointing uphill.

240downer

Dear friend
I have a 1980 240D with a manual 4 speed transmission and wonder if there was ever a 5 speed manual transmission (with over drive?) made for this vehicle? Someone told me that the European models had this available. I would love to be able to reduce the RPMs on the freeway and increase the fuel milage. If you know of anyone with one of these transmissions for sale, please let me know.
Thank you.
Christopher

texases

I'm no help on the 5 speed, except to ask whether a 240D could pull an overdrive? The ones I see on the road seem to have enough problem keeping speed up with the 4 speed.

Mr_Shiftright

I also don't think a 240D has the power for an overdrive. This is why they geared the car low to begin with. I think if anything a 5 speed overdrive would make the engine labor excessively and produce worse fuel mileage, as well as premature engine wear.

Perhaps a 300 Turbo could pull an overdrive gear.

240downer

Dear Friend,
My 240 has plenty of power; it cruises at 75 easily but the RPM is a bit high for my liking. It feels like it should have another gear at about 55 -58 mph. I've just rebuilt the engine at 325,000 miles and it runs strong. I'm wanting to find out if Mercedes made such a trans. Any leads?
Thank you.
Christopher

240downer

Dear Friend,
My 240 has plenty of power; it cruises at 75 easily but the RPM is a bit high for my liking. If I keep the speed down around 60, it gets about 30-31 mpg; if I take it up to 70-75 it drops to about 25-26 mpg. (I'm in California so at 60mph, you'd better be in the slow lane or you'll get run over).
It feels like it should have another gear at about 55 -58 mph. The 4 speed manual has been trouble free but I'm always wanting to make that next shift into 5th when on the freeway. I've just rebuilt the original engine at 325,000 miles and it runs strong.
In response to your comment: if you lug any engine you wll ruin it; but if you've got half a brain and pay attention to the car you won't have any problem. Isn't that one of the reasons for a manual trans?
As much as I appreciate your opinion, I'm wanting to find out if Mercedes made such a transmission. It may have originally been in the 300D but it would still fit the 240D as most of the parts bolt up between 1977 and 1984. Any leads? Thank you.
Christopher

fintail

There was a ZF 5-speed in the 60s (big bucks today) and I know a 5 speed could be had in Euro versions of the W116, W126, W124, and W201 (maybe the W201 also available in limited numbers as a manual in the US?) - perhaps this could be mated.

240downer

Thank you for your prompt reply; I have heard that the 124 trans MAY be a bolt up. Any idea of who might carry such an item? I keep running into 5 speeds for the 190D but I haven't been able to find out from anyone if this will fit.

My wife and I teach in Europe (Italy, Switzerland) twice a year but I have no idea where to look while I'm there. I've never even seen a wrecking yard in either country. My Italian is passable and my German next to nonexistent so it is always interesting trying to discuss a technical matter without a translator.

Maybe the Mercedes club of America might know? Anyway, thank you again for your reply and I appreciate your efforts on my behalf.
Regards,
Christopher

fintail

Yes, I would seek someone in a aclub or perhaps check at a Mercedes-specific forum. There are many people out there with deep specific knowledge of those cars, something which I lack.

Mr_Shiftright

I certainly wouldn't do this until I found someone else who tried it and found it workable. I am still kind of skeptical that a 240D can pull an overdrive gear with shortening the life of the engine, or in the hands of a skillful driver, of forcing so many 5 to 4 downshifts as to make the conversion wearisome to drive. German engineers are clever. They put in 4 speeds for a reason and geared them, and the differential, as they did, for a reason.

hpmctorque

I would value Shifty's advice on this, accept your 240D for what it is, and be thankful it's not an automatic. Well okay, you wouldn't own it if it were an automatic but, seriously, Shifty (and fintail) are extremely knowledgeable about the characteristics of all the W123 series, and you can trust his judgment on the tradeoffs associated with swapping your 240D's transmission.

burdawg

I drove that 280SE sedan for years. At first it felt the same way, going down the freeway or interstate at 70+, it felt like it needed another higher gear. After some time though it was apparent that it was perfectly engineered to have the best gearing to keep it in the rpm range where the engine power curve was best suited for the demand. Yes, at 80mph it was revving at 4200+ rpms, but you wouldn't know it unless you were looking at the tach. On the other end, from a standing start it was designed to start out in second gear, unless it detected a big load or you manually started it out in first gear with the shifter. At first I thought that was silly, why not just make it start in first, but after a while it was obvious that it was fine for almost all conditions. Once I realized it just best to let it do what it wanted then it was fine for almost 100% of the time.
Of course a 240D will behave differently, less power and less rpm's. It's probably best to leave it alone and let it run how it's designed and just use it within those limitations.

jeffm6

I am currently researching, looking, test driving, etc. in hopes of purchasing a mid 80's 300D. This forum has been a great tool in my quest. Today I test drove an 83 300D with 147,000 miles priced at a ridiculous $ 5600. It looks great inside and out, all the power gadgets work(windows, locks, sunroof, antenna, clock) It started right up this wet, 45 degree morning and I noticed no black smoke, and it idled relatively smooth. I did notice the following items and would appreciate any feedback regarding:
1. The temperature as operating registered on the mark between 40C and 80C and the heater blew warm air but I would not call it hot.
2. The oil pressure gauge while driving was at the top of the gauge on 3 and then would drop down when at idle.
3. The brake pad indicator light on the dash would come on when stopped and would blink on and off while driving.
It has been in the same family with 3 different owners since new. It has 2 snow tire on alloy wheels in the trunk as well as the original spare with jack that look that they have never been used. It tracks straight, no pulls or shimmys, I could find no rust. The dealer is willing to let me take it to my own mechanic for the once over.
It drove like a dream on the highway, so smoothe and secure. I will buy one for sure, but perhaps not this particular one.
Thanks, any insights would be appreciated.

Mr_Shiftright

Yep, price is ridiculous but good clean ones can bring $2,500--$3,500. Maybe a touch more if it were a turbo-diesel, a real sharp car could push $4K.

1. The temperature as operating registered on the mark between 40C and 80C and the heater blew warm air but I would not call it hot.

Check the coolant level. If that's not it, then it's the climate control system, which really sucks on these cars. Maybe the heater valve servo is stuck halfway or something, or the electronic control isn't sending the right info to the valve. Not the end of the world, but it could get expensive to square it away. But persistence and the Internet can solve this problem.

2. The oil pressure gauge while driving was at the top of the gauge on 3 and then would drop down when at idle.

Fine, normal

3. The brake pad indicator light on the dash would come on when stopped and would blink on and off while driving.

Might be just a loose wire at the caliper, sounds like. A dealer is required to sell you a car with good brakes.

If it's really clean inside and out with no dents, bad paint, etc, you might offer $4K for it. Sure would be nice if it were a turbo diesel The regular 300D is dangerously slow for modern roads IMO. Merging onto freeways is a knuckle-whitener.

jeffm6

Thanks for the info. I think it is a turbo, according to the badge on the trunk lid.
As you might notice I've got a lot to learn, but I'm in no hurry to buy one. How would I recognize the turbocharger under the hood?
Also, as I drove it the transmission shifted with a noticeable clunk between 1st and 2nd but was smooth thru the rest of the gears. Is this normal. I intend to use this car as a second car, and commute back and forth to work (an 80 mile round trip) probably 3 days a week and use my other car the other days. Is this realistic with a car of this age or am I dreaming? Safety and longevity are my main reasons for selecting this model. Thanks again.

lydia2

So.......have had my 1983 300D since 1984. Sounds like you have found an excellent car. That price sounds good, also. I have had an oddometer/tac, and other electrical snags, which have not hindered operation of the vehicle. Diesel mileage is most excellent both in city and on highways. Last major repair was a voltage regulator because it was not starting up well when the cold set in and the battery was not holding its charge.

No rust? Unbelieveabale! My bumper fell off, when the parts holding it on rusted. Picked it up and put it back on with stainless steel bolts! I live in a 4 season playground, so it has had its share of salty snow. My only complaint has been the lousy radio/tape deck it came with. I may do something about that some day.

Edmunds.com is the best friend I have found. Even the guys at the Mercedes special shops are not sure where relay switches (for signal lights) are and they will charge you five times their cost, then add an hour of labour for the $42 (Burnaby Auto Parts) part and 5 minutes to install it. The mercedes guys at Edmunds are worth their wieght in gold.

So glad to get my emails. Thanx

lydia2

I hear that clunk also. For driving it 80km to and from work this will be superbly economical. If you drive short distances like to school, the mall or such and back or if you open and close the locks often (3x+) you may find that you are taxing the battery. If the locks don't all go down at the same time, start it up and take if for a 20 minute ride and learn not to do the locks off and on too much.

Turbo was hot on this car when it was made. Now there are some standard driven cars that will beat you at the light, (turbo doesn't kick in immediately, needs to get up to some km), but it still does the hills great going up and does not run away on you going down.

Not a dream, but a dream car!

Use the marks on the speedometer to do the shifts down and save your brakes on the hills.

Mr_Shiftright

Oh good it's a turbo. That's a big plus. The clunk is probably...probably no big deal....these transmissions are neck-snappers (I presume this is an automatic?)

Sure you can commute with it, but if you want that level of reliability you will have to make sure the car has everything it needs; in other words, to be used like a regular modern car on freeway commutes, you have to be *active*, not re-active, to the car's needs. So that means "looking for trouble" before it happens.

Things like belts, hoses, dirty fuel filters, battery cables, tires, clean coolant, clean brake fluid, exhaust valves that haven't been adjusted in ten years----things like that---that's what you want to move on ASAP.

These old cars are like bank accounts---if you want to make big withdrawals in longer trips, you have to make deposits now and then---otherwise? BANKRUPTCY!

You should get 22-26 mpg on the highway, which is very good for such a big car. Of course, diesel fuel is as expensive as premium, so that means keeping your car tip top for best mileage. And I wouldn't drive it over 75-80 mph for any length of time.

jeffm6

Yes, it is an automatic. I'm no mechanic but I've replaced belts, hoses, filters and the like on all my other cars, so I imagine I could do this stuff on a Benz as well.
Brakes, valve adjustments, suspension-not too comfortable with-but am willing to learn, or should I say teach myself......ha ha. I rarely go over 65mph in my Scion, not because it won't, but I just don't make my cars work too hard as a rule. I'm going back to look at the 83 300d tomorrow(Sunday-no saleseman) to look more closely at the undercarriage for any rust or greasy, oily areas. Should the underneath be dry or are there parts that are normally covered with sludge at this age? The exhaust system looks relatively new.
Once the Mercedes mechanic goes over it and "if"he finds nothing major in need of repair I will offer $3500 and not a penny more. What do you think?
Many thanks.

Mr_Shiftright

Since there's a middle man I doubt he'll take that offer, but it's fair enough. I'd go up to $4K.

one thing to check is the air filter. See if it's filled with oil blow-by from the engine.

Yeah, there will probably be some oil under the engine. Those diesels are old cars now, and you can't expect perfection.

Check for torn boots in the rear axles and see if the cruise control works. Also it would be great to check if the instrument panel lights work, but it needs to be dark to do that.

Oh yeah, check the coolant level because of the lukewarm heat issue.

jeffm6

I took a flashlight and crawled under as best I could. The oil pan is pretty much covered with a layer of shiny sludge and the two lines on either side of the pan (fuel or coolant lines? I couldn't tell) are also covered and are wet with what I think is fuel as it is black and very thin. A small drip stain on the pavement about the size of a baseball. The rear differential also a little oily. I saw no cracks in the CV joints but the boots look pretty old but intact. No coolant leaks that I could see. Couldn't pop the hood so wasn't able to check for oil blow-by. How would you know if there was a fuel leak, would the top of the engine be covered in fuel? The very center hub on the front wheels looked like it had been dirty with brake dust and wiped clean even though it has the brake dust shields on all wheels?
Checked out the dieselgiant.com.mercedes diesel maintanence tips website, it was great, thanks.
Happy New Year.

Mr_Shiftright

All sounds pretty normal for an old Benz diesel.

A good tip is to start the engine COLD. If it fires right up, instantly, the engine is probably pretty tight. If it cranks and cranks when cold, that is not a good sign, although not necessary a disaster. It could mean old glow plugs, it could mean low compression, it could mean tight valves. Oil in the air filter is definitely a sign of some engine wear and blow-by, but again this isn't a disaster--just a sign of old age.

A diesel fuel leak would really stink up the front of the car.

nate811

I've had my 99 E320 for about six months now and have not had any issues. Recently, an issue has begun: when I start the car the blower fan will not immediately come on. After maybe a minute or 10 minutes the fan suddently starts to blow the heat. I have adjusted the climate control settings and no changes seem to have any affect, the fan just starts to blow randomly. Once it comes on, the speed can be adjusted and it has always stayed on.

I don't have experience with this type of issue, but am curious given that the car is designed to have a slight delay in the fan when started. Any suggestions?

mason84300td

Hello I have a 1984 300td with 100,000 miles, it has no rust, looks and drives pretty good, but it has a few of the problems I have been reading about. For example if I plug the car in it starts without any hesitation. If not, it will not start.I changed both fuel filters, glow plugs and fuel lines and am still having a hard cold start and a low idle (600-750). I am in upstate New York today it was 2 degrees. I don't know if using anti-gel additives will do any damage or should I just try to find an outlet wherever I go?

Mr_Shiftright

Yes at 2 degrees you DEFINITELY need additives. And even then, you might have trouble.

let's face it, in Alaska the big rigs often run all night long at the truck stops. If it's cold enough, a diesel car can be near impossible to start.

you might also consider thinning out your fuel with kerosene, and getting the biggest, baddest a** battery you can find. And additives. And starting ether.

2 degrees? Man, that's tough for an old diesel.

burdawg

I can't say for your specific car, but the MB's I have owned in the past with climate control won't blow any air until the heating system warms up to a specific point. Maybe with the colder weather now it's just taking longer to reach that point? Keep an eye on the temp gauge and see if the blower starts at a certain engine temp consistently.

texases

Any way to put a block heater in these? I'd hate to deal with a gasser at 2F, much less a diesel!

mason84300td

Hello, I was told to use synthetic oil, but also told if the car had any minor oil leaks would turn into large leaks.

Mr_Shiftright

Not true. Old wives tale.

lydia2

I was told that my 84 300D which has never had synthetic oil should NOT have a change to that now.

Is there a relay switch or such that controls the lights in the climate control/radio panel? I have light in the guage (gas, oil, spedometer, etc.) panel. I did manage the new relay switch for the signal lights, so I am wondering if there is a similar cure for this problem.

lydia2

Plugging it in in winter is almost a given.

However, how to start is needed info. In WINTER-- First time for the day you must press the accelerator firmly to the floor 3 times. THEN --after the glow plugs go out--you turn the key on without pressing the accelerator. The next time on that outing, having parked and restarting, you need to press the accelerator only 1 time to the floor, THEN--after the glow plugs go out-- turn the key on without pressing on the accelerator.

Short rides with a diesel in cold weather is hard on it. I often idle it (locked doors) if in and out quickly on a short trip. (NO idle laws here, yet)

Mr_Shiftright

Well you were told wrong and that's that. It simply isn't true. You can use synthetic. I did the same thing in my old diesel and it was fine all across the desert and back. And my old Porsche, too. Both were very high mileage engines.

As for the climate control lights, no, those teensy lights don't require a relay. A relay is a BIG SWITCH that is activated by a small switch. The idea is that a small switch cannot handle the amount of current needed but a big switch can absorb it. Signal lights can't be activated by a tiny switch, hence you need the relay or 'flasher".

But the climate control lights use very little electricity and don't need the protection of a relay.

brakeengr

I switched from "regular" oil to Shell Synthetic for diesels (I believe it is a 20W50- not sure, but I got the gallon containers from Autozone), and all is fine- actually, I think my 300D runs better after the switch.
As for the lights- check all the fuses.

Mr_Shiftright

I think the diesel engine appreciates the synthetic in cold weather as well as warm. The synthetic oil seems easier for the crankshaft to plow through on a cold day, and diesels need all the help they can get in cold weather--especially the old ones.

lydia2

Do you use a different synthetic oil for winter, or the 20W50 all year?
Is you car a 1983/84 300d?

Yes, I checked the fuses; they are all o.k. I figure it's wiring problem in that the oddometer, cruise control have not worked as well, for many, many years. The light problem came with the paint job that resulted in electrical mishaps or age and whatever happened.

Mr_Shiftright

cruise control is probably the amplifier behind the console. Very common problem.
$100 rebuilt on the Internet.

brakeengr

I use the same oil all year round- no changing in winter time.
I have been very happy with the synthetic, especially in winter- engine seems to run smoother- you can tell the difference when it just "purrs".
Mine is a 82 300D turbo; 255K+ miles.

rleitch

Is there not a concern with older cars that by shifting to synthetic oil, there could develop leaks in the seals? I thought I had heard this claim somewhere, I had tried synthetic in my '77 300D years go and switched back to regular just in case.

Mr_Shiftright

No basis in fact.

bumpy

Maybe not for a 300D, but if you go back far enough to when engines still had rope seals, the synthetics will "weep" through the seal because of their extra slipperiness. Something to do with the molecule shapes.

Mr_Shiftright

Dunno. Could be but rope seals go really far back, and besides they leaked like crazy themselves.

playernulla

I keep reading the advice against buying high mileage diesels and how it is better to buy one with all the receipts in excellent condition etc. In my part of the world here in Boston there are few if any with mileage under 180,000 and those that are cost upwards of $4,000 while a high mileage one can be bought for $2,000. These cars are now 20 years old so one owner documented cars are getting rare.

I dont make that much money and put 30K miles a year on my car and have been driving 180K plus mile diesels for years and never once had an engine or transmission go of natural causes. Nuisance stuff sure but nothing major. If I bought a newer car I would drive upwards of $5,000 equity offf in one year and I can't lease with that many miles so I have to buy and have a $700/month car payment for anything good enough to take that many miles. If I buy a high mileage Benz for $2,000 and drive it for three months without a major repair I break even on the car payments and can throw it away. If I luck out and drive it for three years (90Kmiles) like I do with a $500 repair ever three months or so I save a ton. If an engine or tranny goes I can toss it and buy another. There is no other car you can do it with. I have tried Volvos, Saabs, BMWs and Subarus and got burnt by them all.

I test drive the car and if the engine sounds good and doesn't smoke, the tranny works well, and the body is decent, tires good and brakes sound, the chances of getting 3 months is close to 100%, chances of a year are 80+% chances of getting 3 years are much better than 75%. The mean time between major failure on MB's is very long. I have driven three of them from 180K to up over 320K and the only major failures was one blown engine when someone put gas in the tank instead of diesel and a blown tranny when AAA towed it on the rear wheels 45 miles (bad starter).

I say if you have $2000 to spend there is nothing safer, more comfortable, with best chances of coming out ahead than a high mileage diesel mercedes. I hit black ice doing 85mph on rte 89 in NH and was going sideways and was able to get control without rolling or going off the road like a dozen other cars did that night. What other $2,000 car would want to be in when that happens? I am assuming that you dont care about some windows not working, maybe no air (giant sunroof), just safe reliable low cost transportation. Not to mention how easy they are to fix yourself if something breaks to save money.

Not everyone has $3,000-$5000 to spend and you can not throw away a $5,000 car if something goes wrong like you can a $2,000. One mans opinion.

Mr_Shiftright

I guess it depends on how one intends to use the car and one's tolerance for things not working, or if the car is spewing black smoke behind it, or how good the brakes might actually be in an emergency.

You know, you get what you pay for, so you're quite right that one can make do with a $2,000 high mileage diesel if you are able to do stuff yourself and aren't too fussy.

So I agree with most of what you say except your "odds" of surviving 3 years. I'd say more like 20%, not 75%. I don't think the vast majority of people have the good luck you have had with old, tired, beat-up MB diesels selling for cheap.

Whenever anyone asks me to look at an old diesel for them, I can always find thousands of dollars of needed repairs---but the cars still motor down the road. The suspension is more or less dead, the engine smokes, no AC, some windows don't work, the driveshaft rattles, one CV joint is knocking, the brakes groan and vibrate (but they stop), the belts and hoses are old, the coolant is brown muck, etc.

So my feeling is why not buy a car for twice the price that has all this stuff done already? You'll be paying it out sooner or later anyway.

Old cars are fun but they have to be safe.

If you can find or make an old diesel safe for $2K, then great.Go for it! But I don't really agree with the argument (not that you're making this argument--NOT implied) that just because a person only has X dollars, this gives them the right to drive a smoking dangerous old beater.

As for driving on ice, that's really about tires and luck IMO.

playernulla

I agree with what you are saying. The cars I have been buying for $2,000 havent descended to the levels of disrepair you describe. They are generally good solid cars that have been well maintained but just have high highway miles on them. Kind of the pick of the litter of high mileage cars which are out there if you look hard enough. If the car is solid with just a few little things wrong, the suspension is tight, the engine is strong, and the tranny shifting well but the car has in the high 200's they can be good gambles in my humble opinion. They have often been owned by executives who do a lot of highway driving and take care of their cars.

Mr_Shiftright

I suppose any high mileage car is a gamble. I don't think any old Benz diesel would last any longer than a Toyota Corolla, mile for mile, with the same care given to both.

What gives old Benz diesels their mythology is that they are well built. They can "look" great 30 years later. But most of these "high milers" have already had head work, transmissions and thousands and thousands of dollars in repairs done to them.

We who buy them cheap at the end of their lives don't know about all that in most cases. We didn't make the deposits, we are just taking the withdrawals for all that good care some of them had.

But you have the right idea. If it's over 200K, don't pay a lot of money for one. I couldn't agree more.

timingchain

Hi Mr Shiftright,
I'm experiencing a couple glow plugs failing in my 82 300SD. This will be the third time this year I've had to replace 2 or 3 of them (I have not kept track of how many/which ones previously failed). The first time I used OEM, the second time I had to use Autolite due to availability. I will go back to Beru or Bosch, but any thoughts on what else could be causing the failure or how to test for it? The glow plug light doesn't do anything weird and I don't leave the key on/engine off or do anything else that would obviously run the relay excessively.
Thanks for your time.