Buying a 300D. What to look for?

[Guest Close David]

After looking for about 12 months, I am ready to buy myself a Diesel and have decided the Chariot of Choice will be a 300D. ( although if I could find a 300TD wagon, that would be better still!)

I have a found a couple of cars to go look at the next couple of days and am wondering if there are any particular things to look out for or be wary of?

As injectors and pumps seem to be the most likely things to wear out and be the most expensive things to replace, is there any way of telling their condition or can they be practically tested before purchaseing a vehicle?

Has anyone recently had a pump or injectors replaced and can give me some idea of what this would cost? If I find a vehicle that is otherwise sound but has a problem with these components, it may be worth buying and having the pump injectors done if the initial price is right.... and I have an idea of the cost of the repairs. Can anyone reccomend anywhere in Sydney I could ring for an estimate?

Is there any average life expectancy of the pump and injectors or will any 1980 or there abouts vintage vehicle will already have them done by now through time if not milage?

Are there any other components that typically fail after a certain milage that should be looked at like transmissions etc?

Any info anyone can offer in what to look for when checking these cars out would be appreciated!

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: Buying a 300D. What to look for?

Hello David

The only check that I am aware of is to remove the oil filler cap while the engine is running. If a lot of smoke comes out, the engine is worn and probably should be avoided.

Tilly

[Captain Echidna Senior Member Find all posts View Profile Close Captain Echidna]

Re: Buying a 300D. What to look for?

There was a good thing on the net on "spoting a 123 dog" but I cant find it. If it is the w123 range, there are a few things to look for. Steering boxes often wear badly. They can be adjusted (there is a lock nut and an allen key bolt which winds OUT to tighten the box. Check it on full lock however to check it doesnt bind though) but new boxes are expensive. Some have self leveling suspension, which is expensive for parts, if you can avoid it do so, as rebuilding it requires specalist equipment to fill it with oil and get pressures correct. (if it has a big resvour with light oil in it under the bonnet, it is self leveling) If the rear end is sagging, it is an indication it needs attention.
And despite mbspares in the act which do good priced spares, there are few more expensive cars to own than a cheap to buy merc.
Mind you I am an amature at this, I am sure Tony from west oz (who has turned mercedes ownership into an art) will have some excellent things to look for...

[Tony From West Oz Vice Chairperson of WARFA Find all posts View Profile Close Tony From West Oz]

Re: Buying a 300D. What to look for?

Chris,
I have been reliably informed that repairing a SLS will be cheaper than replacing it with springs and shockies AND the car will ride much better too.

David,
Tilly mentioned that the amount of smoke from the oil filler cap can give an indication of engine condition. This is true, but I would be worried if there were no smoke from there. What you expect is smoke like a boiling kettle steams, but not so much that it blows the filler cap off while you are removing it. Have a look at other diesels to compare.

The things to look for are:

• cold starting: The GP light should come on and then extinguish after 5 - 10 sec (1980 - 85) or 30 sec (1977 - 80). The engine should catch on the first revolution and be running by 2 full turns of the engine.
• Vacuum issues: The central locking, auto tranny shift changes and engine shutdown are vacuum operated. Check the operation of all of these systems. The auto tranny should shift smoothly at low throttle settings and more harshly and later for flat out acceleration.
• Oil Leaks: These cars can be oil leak free. It can be difficult to achieve, but it is possible.
  • Oil leaks from the rocker cover are fixable as are oil leaks from the fuel pump / IP side plate.
  • If the rear main oil seal is leaking, you will need to pull the engine to repair it.
  • The sump is in 2 parts, leaks from the bottom pan gasket are easily fixed, but the upper oil pan gasket again needs the engine to be removed.
  I have not seen leaks on any of our 300Ds which needed engine removal. The rocker cover gasket can leak oil down the back of hte engine, making it look like the rear main needs replacement.
• RUST: Common places for rust are:
  • Rear Window, passenger side between corner of boot lid and rear window.
  • Boot floor
  • Under doors
  • Around hinges for the bonnet
  • Floors
  • Bottom of front guards.
  • Passenger side windscreen wiper pivot point can rust (I have seen this on many W123 Mercedes.)
  Interior rust indicates that fixed glass seals are leaking
  
  
• Power: The 300D is not a sporty modern car. If you wish to be the first off at the lights, then you had better arrive at the lights just as they turn green, because the 300D will not win any races (except against auto 240Ds and Gophers)
• Seats: The drivers seat sags with age and broken springs. I have repaired mine by stuffing a 'pool noodle' wrapped in denim in amongst the seat springs to restore the comfort and support)

[bruceT Senior Member Find all posts View Profile Close bruceT]

Re: Buying a 300D. What to look for?

What Tilly has referred to is the result of blowby. A 300D without any blowby would be a very rare beast indeed, so I would not necessarily eliminate a car that exhibits this, unless it was really excessive. I would try to establish if oil consumption was excessive. Also, have a mechanic check the compression and do a leak-down test if possible. These engines are quite noisy and exhibit a distinct clatter, but try to identify any strange knocking or grinding noises over the clack clack, and run away if you hear any! For all the clatter, it should not run "rough".

Don't be put off by black oil on the dip stick. It goes black soon after an oil change! However, check the service history. These engines need the oil changed every 5000km (ideal). 10,000km is too long.

The Bosch injection pumps are not usually a problem and if the engine is running nice and evenly, the pump should be fine. The glow plug dash lamp should go out after about 30sec and the car should start within seconds without much cranking at all. The oil pressure should go up to the max "3" mark within a second or two of starting. When the engine is at operating temp, the pressure should drop to the "2" mark at idle, and go up to "3" immediately you accelerate.

If an auto, the transmission should not flare at any changes. Check that it does not take more than a second to engage reverse. Changes should not be too harsh or lazy. Check that the kick-down works. Often they don't because the accelerator pedals of these cars are always pushed to the floor at all times

If it has self-levelling, check that it works. The ride for rear passengers should be smooth and not bouncy. If it bounces, the self-levelling is shot. Check the plastic oil reservoir. If depleted, the bladders in the actuator cannisters have burst. They are easy to replace, but new cannisters can cost $300 each. When it's working and adjusted correctly, the ride is so sweet. The ride height is also easily adjusted if the rear end sags. Allow about $75 for new MB hydraulic oil too.

Check for clunking in the rear. This is usually the upper bush on the hydraulic strut, but it could also be the cv joints are stuffed. Check the boots on the cv joints are intact.

Check for play in the steering. Vibration at speed could be the steering damper or worn suspension components. Check the tyres for uneven wear for a clue.

Vacuum door locks often don't work. They can be a pain to sort out and you'll need a vacuum tester to find the leak. However, it not expensive to fix if you do it yourself.

Do all the guages on the instrument panel work? Importantly, does the odometer work? If not, the true km travelled by the car could be in doubt.

The vacuum on these engines comes from a pump on the engine. Check that the brakes are nice and firm and work without too much effort. If the effort is high, the vacuum pump could be on the way out. The pumps can be serviced with a rebuild kit that is not expensive, but it's a bugger of a job that requires the removal of the radiator.

Check for damp or rust under the carpets. It is usually the result of the air-con overflow pipe having perished.

Does it still have it's original Becker radio? If not, ask the owner if he has it, even if it doesn't work. They can be repaired and they are as scarce rocking horse sh*t. If it has the auto-tuning Becker Mexico, they work and sound great and were the first auto-tuning radio ever made. I believe they were a $2000 option in the 70s.

Finally, do a take off test. You should not be able to squeal the tyres and
0 to 100km/h should be under 40 seconds. If it has a turbo, start smiling, because you'll easily do 0-100 in under 30 secs

[Guest Close David]

Re: Buying a 300D. What to look for?

Thank you all for the very informative replies!
I have been around and played with cars all my life but this is new territory for me and I now feel much more confident in what I am looking for. Obviously these things are quite different to your run of the mill Holden’s, Fords and Jap cars… Although I have played around with Subaru self leveling suspensions but they are Pneumatic not hydraulic.

I'm just having a small freak out here..... Everything I have read about these cars has said they are no dragsters but IS 30-40 Seconds to 100K what they do really or are you guys having a lend of me???

I have driven 2 ton tippers and pantechs that were much livelier than that! I will be the first to admit I used to be a fast driver and was quite comfortable with the idea of a cruiser rather than a racer but holdingup traffic wasn’t something I was counting on!
I don't think I have owned a car since my very first bomb that wouldn't do 0-100 in ten seconds or well under! When people said slow, I thought like older style 4 Cylinder Auto slow…15, Maybe 20 seconds, but 30-40???
That would give them a 1/4 mile time of about an hour and a half!

This is really going to get some taking used to! How do the things go up hills and towing a trailer? Do you ever get there or do you allow double travel time for any reasonable country trips? I wonder how hard it would be to put a DIY turbo on these things or if there are any * Cough* -Performance- enhancements a person can do.

I like the look of the cars as they have a real classic appeal and I believe them to be Safe and comfortable but I wasn't expecting them to be quite so lethargic. I’ll still certainly be buying one though, sonds like the answer to my dreams to slow the leadfoot Mrs. Down!

Anyway, thanks again for the input and if anyone has any other tips or info I’d be pleased to hear them.

[Terry Syd Senior Member Find all posts View Profile Close Terry Syd]

Re: Buying a 300D. What to look for?

"the answer to my dreams to slow the leadfoot Mrs. Down!"

My brother thought that to when he got his 300D. Only problem was, his wife refused to drive it because it was so slooooow.

Anyway, he is quite happy with having run it with no problems on B100, low-conversion, unwashed biodiesel for the last three years. Although he just bought a 300TD so the wife will start using his increasing oversupply of biodiesel.

[Captain Echidna Senior Member Find all posts View Profile Close Captain Echidna]

Re: Buying a 300D. What to look for?

I would go and test my 0- 100k/hr time, but I cant find a calendar
I regulary tow a trailer with mine (with a few drums of filtered vegie oil, and the stuff that wont fit in the boot with 2 kids and a wife) it does slow things up a bit, but about 100-110 on flat ground. Come to a hill however.....
Unladen about 120k/hr top speed. Mind you I dont think mine is the best example. The speed (or lack of it) is not really a problem when you get used to it. Mind you if you own a modern petrol car and a merc swapping can cause a few surprises, as pushing the accelerator down hard becomes a habbit.
I think the self leveling suspension is both hydraulic and pneumatic. I have heard the same as Tony that it is not worth removing it over repairing it, but if you cant pick between 2 cars and one hasn't got it, I would be tempted to pick it. The rear shockers are about $400 each.

(After posting this I went and tested 0-100k/hr times. About 30 seconds. Amazingly enough when you get used to it, it is cool, you just sit back, enjoy the scenery, the wife probably goes to sleep in the comfy seat, and you cruise off. As for performance upgrades I did see a chrome rocker cover on e-bay! )

[Tony From West Oz Vice Chairperson of WARFA Find all posts View Profile Close Tony From West Oz]

Re: Buying a 300D. What to look for?

Smoke from the exhaust.
If at warm/hot idle, there is whitish smoke, this indicates that some unburned fuel is leaving the engine. This can be due to injectors which need servicing. This can cost from $50 each upwards, depending on condition of the injexctors.
Black smoke on full throttle acceleration can be due to dirty air cleaner or over fuelling (someone cranked it up to get more power). Use biodiesel and it will clean up.

Valve adjustments should be done around 25 000 Km intervals. If your 300D is more sluggish than described above, a valve adjustment can do wonders, as these valves tighten with wear, not loosen as in some other engines.
If the valves have been set and you still have a sluggish engine, do some 'italian tune up' runs, to burn off the carbon build up in the engine. This may result in some sooty exhausts as the carbon burns off. If still sluggish, have the injectors checked as above.

The injectors should deliver a fine cone of fuel mist as they inject. If they dribble or squirt, they can create smoke at idle and reduce engine power at full throttle.

[Tony From West Oz Vice Chairperson of WARFA Find all posts View Profile Close Tony From West Oz]

Re: Buying a 300D. What to look for?

You can buy CD or DVD electronic manuals on eBay. I downloaded one from an internet website where it was hosted for people to look up online. It was at http://skinnerbox.steaky.org/Service/W123/Main.html. I have not revisited the site recently, so check it out. I used a Website Copier programme to download it. I used WinHTTrack from HTTrack Website Copier - Offline Browser
Tony

[biofuelbaby Junior Member Find all posts View Profile Close biofuelbaby]

Re: Buying a 300D. What to look for?

David
Your info says Bankstown.
I run a 240D auto.
Consistently one of the slowest cars on the road.
I have a mechanic in Rydalmere, sign says Dr Gas near Rydalmere station on Victoria rd. He installed Dieselgas turbo on his 300D wagon and the thing now has big increases in power,torque and acceleration. He's trying to talk me into a conversion but I'm not particularly interested in a huge power increase. What it does do is reduce particulate emissions, which for me is the biggest environmental problem with old diesel engines.
The conversion can be set to mix LPG, CNG or methane directly into the cylinder with diesel.
Should qualify for the new gas subsidy.
Personally, I would do it straight away if there was reliable commercial availabilty of biodiesel and biomethane.

Cheers

Phil

[Guest Close David]

Re: Buying a 300D. What to look for?

Thanks again Gents for the valuable input.

In all seriousness Tony, How on earth would a person determine if a car that does 0-100 in Say, 35 seconds, feels anything but sluggish??
I think I am going to have to get very used to driving one of these in order to know what they feel like first. As mentioned, getting out of a petrol car that is sluggish pulling 10 secs to 100 into one of these will cause some interesting sensations.

Thanks for the info on the white smoke... I always wondered what that indicated. I was thinking of taking the thing to a diesel place and asking them to tune it for power over economy. I don't think anything is going to make much of a difference but maybe slow will be better than completely painful.
One thing I was intending doing is adding water injection to keep everything in the engine clean and free of any buildup especially as I am planing to convert it to run SVO as well. May not be needed but I figure can't hurt if it dosen't help. And besides,If I can't win any street cred with it's speed, Maybe I can impress someone with it being tricked out with technology!

Terry, My Mrs is very likely to be the same as your sister in law. I have already wondered if these Merc's came with different diff ratios in other models so I could put in a lower ratio to give the thing a bit more pep even if it was flat out at 80Kmh or at least swap the speedo drive gears so she thinks she is going faster than it feels

She's too smart though to fall for this. I tried what I thought was a clever ploy to stop her running out of fuel all the time....I pulled the fuel sender out of the car she drives now and bent it so when the gauge reads empty, there is still almost 20L of fuel in the tank.
You guessed it, she still runs out of fuel despite the empty indication on the gauge, a dash light and beeping noise and having the best part of 20L of fuel in which to drive to a servo to fill up after all this happens!

I'm thinking of replacing the indicator light with something like a porta flood and the electronic beeper with a ships fog horn to see if that gets the message across Why is it that the ONLY place on earth she Dosen't love to spend money or buy anything is a petrol station??

" As for performance upgrades I did see a chrome rocker cover on e-bay! "
As I was driving home this morning I saw a 380SE with a boot spoiler!! Imagine if I got one of those AND the chrome rocker covers! I'd be eating 1954 Skoda's for breakfast....Almost!

[bruceT Senior Member Find all posts View Profile Close bruceT]

Re: Buying a 300D. What to look for?

You can buy CD or DVD electronic manuals on eBay. I downloaded one from an internet website where it was hosted for people to look up online. It was at http://skinnerbox.steaky.org/Service/W123/Main.html. I have not revisited the site recently, so check it out. I used a Website Copier programme to download it. I used WinHTTrack from HTTrack Website Copier - Offline Browser
Tony

That site has been locked for some time. This one worked yesterday!

There are a few other models here as well...

Mercedes Benz Service Manuals