Project: 1981 Mercedes 300TD
 

Like the title says I just bought a 1981 Mercedes 300TD for all of $209!! It sat for two years but starts up decently well, when I start it now but when I drive it it is very very slow off the start and reached 40mph and maxes out. It has 245,000 under its belt and I dont know when the last time some one did any maintenance.. If you guys wouldn't mind could you give me a list of what you would do to it? Also I am trying to remove the head unit and I have the ash tray pulled out but cant seem to get the unit out any pointers? Also is there any common stores that might sell the little tube fuses?

I am a senior in high school who bought this car for a project so I am trying to keep the amount I spend to a minimum, all help is greatly appreciated and your site rocks!

Andrew

Hi Andrew welcome to the forum.

A maximum speed of 40mph is a bit on the slow side - I'm guessing it doesn't have a manual gearbox - so does the auto box shift through all 4 gears?

As for what I'd do first:-

1) Change the engine oil + new filter

I am not sure if it shifts through all 4 gears, my mom drove it home so I assume it does. I just drove it around the block and i felt it kick through 3 gears I dont think I could get it going fast enough on my street to pop it into 4th..

As far as maintenance goes how does this kit look? Would I see a performance increase?
http://www.dieselgiant.com/diesel_parts_for_sale.htm#Diesel%20Extreme%20Makeover%20Filter%20Kit

How do I remove the radio? I have a picture of what i got it down to..

Thanks for your reply!

i would change the oil and filter, and both of the fuel filters, and adjust the valves. clogged filters could explain the sluggishness. could also be the throttle linkage. to check: sit in the car with engine off and floor the gas pedal. then have someone else pull the throttle linkage under the hood and see if it opens up further. ie: the pedal is not opening the throttle all the way. if it fails this test, you need to adjust the linkage and bushing so that the go pedal does its job.

radio: remove ashtray, and remove the retaining unit via two phillips head screws, and unplug the lamp connector. you should then be able to depress 2 tabs to get the head unit out. you have an aftermarket unit, so i dont know where they are...

there are lots of "free" things you can do to get it in good shape, if you can turn a wrench and follow instructions.

do some searches! there is a wealth of info on the interwebz! check out benzworld too... congrats on your new baby. post up some pics of the car!

To remove that radio - you need to find some sort of thin bit of metal that fits in the little release holes on either side of the radio. (The FSM procedure for the factory fitted radio is different - it looks to me like you don't need to do that)

The release holes are at the left hand side and the right hand side of the picture you posted - in the middle of the vertical sides between the black bit (the radio) and the silver / metal coloured rim that encases the whole radio. There are 2 little square cut outs.

As for the filter kit - well the link sends me to many filter kits. If you haven't got any money the trick is actually not to spend any - however - an oil filter and an oil change really are a must after a car has been sitting for a while.

Take out the air filter and see if you can clean it up - tap it on the floor and see what falls out!

Oh I agree with the fuel filter comment made in post #4 - you'll have two on your car. The primary is (or should be) a see through plastic thing. This is the small one. You should also see a spin on one nearer to the front of the engine - the secondary and big one

Even so - start off slow and do one job at a time - don't end up doing too much in one go.

You've got a turbo on that and it might not be working. There's a plastic line that runs out the back of the intake manifold. It can get plugged up. It's the overboost control line. You can follow it from the manifold to the overboost controller onthe firewall then over to the ALDA on top of the injection pump. Make sure it's all attached and clear.

The air filter is pretty damn clogged and needs to be replaced asap! The oil is pitch black so it needs to be changed to. I was just looking at that kit cause it comes with every thing needed including valve adjustment tools.

Thanks for the pointers on the radio I need to get our there and play with it some more.. It didnt come with the face plate so I need to pull it out and see what model it is and order a new one.

Ok heres a question that my parents want to know say I spend 500 for all the engine work, head lights, tail lights, and any other little pieces to make it look alot better how much is the car going to be worth if I sell it?

I posted up some more pictures including the little pre fuel filter or what ever it is. Should there be fuel in that cause I haven't seen any? Also with the head exhaust on top is that the piece in the picture what I use to connect it?

Thanks for all the help!

SD's have the modern fuses--instead of the torpedos?

Couple of clarifying items. You don't have a TD. A TD is a station wagon, not a turbodiesel. You have an SD. It's different than a 300d or a 300TD. That is a fuel filter but it is not placed in a fuel line. It's in a vacuum line and it's there to capture any oil should the vacuum pump or shut off diaphragm fail. The fuel filter is similar but it is lower, down near the frame rail with a larger black hose going in and out and entering the lift pump on the side of the injection pump.
Yes that hose is used to connect the valve cover (not head exhaust) breather to the air cleaner and oil separator. Yours looks like it could be a jury rigged hose. Most hoses that fit there are flat.
Depending on the cars overall condition, a well running SD with that kind of mileage should be worth between $1000 and $3000.
A very dirty air filter could account for the lack of power.

The hose is correct for that year, Mine's an '83 and has the same round hose, the new ones came in '84 I think... Anyway, I agree with Kerry about the filter. When I bought mine it was black and soaked in oil, full of every bug's corpse you can name. I replaced it and it felt a lot better. Also, change your pre-filter and your main filter, that should help the speed. Check your banjo bolt (search banjo bolt within this forum for help) as they tend to clog and give you a very slow ride. Right on top of your injection pump there's a little thing called the ALDA. See whether it has a plastic cap on it or if you can see the screw (which would mean that it has been tampered with in the past, like I have done with mine) as maybe someone who didn't know what they were doing turned the ALDA screw the wrong way.
It's a nice ride :) Welcome to the forum!

Still haven't figured out the dang radio I will have to give it ago tomorrow.. I also bought some more fuses today, I re placed as many as I could but the store didn't have any more in stock so I need to pick up more. As a result of some new fuses all of the dash gauges work now besides the tach :( maybe more fuses will help that?

The other thing that got my attention was that the gauge on the dash not sure what it is went all the way up above three when I started it? What does this gauge watch? and what should i do to fix it? I put a box around it in the pictures below.. Thanks!

Thanks for the welcome, I have already cleaned the banjo bolts and lines but they weren't in that bad of shape. I also picked up a new WIX air filter for all of $13 bucks and installed it.. I have yet to take her for a drive with the filter, will give it a shot in the morning.. Where exactly can I find the pre filter and main filter pictures would be very useful! Also can I buy these filters from my local car parts store? Thanks SO much!

EDIT: The cap on the ALDA has not been removed should I look into adjusting that? Could you fill me in as far as that goes?

Thanks for clearing those terms up for me! :cool:

Andrew,
Its great to see some one so young interested in a car like that !!
You will find all you need to know to fix it on here. If you need parts, make sure you click on the buy parts link at the top of the page, they support the forum, so give the 2 of them a try, if they are competitive, go with them.
That air filter is a mess !!
I would get the car running properly before I got too excited about the radio.
There is plenty on here about adjusting the valves, probably they will need doing now and again in 1000miles.
Dont try & run the car on WVO. It will give you problems.
That gauge that gave a full reading past 3 is the oil pressure gauge. At idle it should be over about 1 1/2 & running it should be up over 3.

Sounds like you dont have a work shop manual for the car. You should do a search on google etc & see if you can find a free electronic one. In time you may decide to get a proper hard copy.
If you do a lot of searching on here you will find most of what you need to know.
Probably to get you going, filters from your local parts store will be fine. There are plenty of threads about the best oil on here.
when you change the fuel filter make sure you follow the procedure on here or you will kill your battery trying to get it to restart.
get it running well on regular diesel.

Good luck with your car !!

Make sure you keep us up to date on your progress so we can all help you with your learning.

One more item: The oil is always black in these cars. Not saying you shouldn't change it, just that 10 miles after you change it, the new oil will look just like the existing oil.

What's your goal: fix and drive, or sell and make a small profit? That will affect what you do and what you spend.

It sounds like you're new to diesels. Diesel oil is different, and mercedes uses odd filters, so they may not be available locally.

A 40 MPH top end could have a lot of causes, one of which is the ALDA line. Read the diesel giant page for maintaining it, but I wouldn't recommend adjusting it yet. Just maybe clean the connections and make sure the lines are intact. I inadvertently left one loose and it caused the car to top out around 50 mph.

Your radio probably needs a brand-specific tool to release the clips. The HU clips into the DIN frame (the sheet metal box). You might be able to slide out the whole DIN frame if you're lucky. If the installer bent the tabs inwards, then you may have trouble. Reach under the radio and try to wiggle it forward. Don't force it if it sticks.

Take the digital pic to a radio installer and ask them about the removal tools. They may recognize the brand from the slots and loan them to you.

You might eventually have to remove the A/C panel above the radio to get it out if you can't find the tools. This isn't hard.

Before you drive it much, I'd thoroughly check the brakes. Sitting for two years isn't a good thing.

Where in Texas are you?