Hi there,


I just purchased a new to me 1974 240D. I'm pretty handy with gasoline engines but took one peak under the hood and do not know where to start troubleshooting.


Hopefully, you guys can steer in me in the right direction on were to start repairs/maintenance. I really appreciate any help!


1. I checked that oil cap and it does a pretty good dance short of blowing off valve cover.


2. The car will not shut off with key (must do manual under hood).


3. The car is really loud and no low end power. Oil pressure gauge reads max pressure while accelerating.


4. Speedometer does not work.


5. About 5 inches of play total in steering, car wanders quite a bit at highway speeds.

Ok,
1 - Normal for high mileage

2- Normal - your car shuts off by pushing the "gorilla knob" back in to my knowledge

3- Probably normal, as for pressure it should always be pegged while a bit above idle, these engines run around 100psi pressure

4- Check if your speedometer cable is connected or broken

5- Semi-normal, these steering boxes get quite vague but that sounds a tad too much, check your tie rod end ball joints for play and maybe tweak the steering box adjustment. Might be a lost cause though, be prepared for a new / rebuilt steering box. Think there's a guy on this forum who rebuilds them.

Welcome to the club

__________________
1978 300D, 373,000km 617.912, 711.113 5 speed, 7.5mm superpump, HX30W turbo...many, many years in the making....
1977 280> 300D - 500,000km+ (to be sold...)
1984 240TD>300TD 121,000 miles, *gone*
1977 250 parts car
1988 Toyota Corona 2.0D *gone*
1975 FJ45>HJ45
1981 200>240D (to be sold...)
1999 Hyundai Lantra 1.6 *gone*
1980s Lansing Bagnall FOER 5.2 Forklift (the Mk2 engine hoist)
2001 Holden Rodeo 4JB1T 2WD

Places to start:

1: This is due to blowby, aka worn engine. Start with a compression test to determine how worn the engine is. Many of these engines keep on driving puffing out clouds of blowby for thousands upon thousands of miles. The joys of owning a diesel.

2: This is common. Start troubleshooting your vacuum system starting at the vacuum pump. You should be making 20-22"Hg vacuum if the pump is healthy. If you do, start replacing rubber vacuum hoses and fittings. Buy, rent, borrow, or steal a hand vacuum pump and test circuits to determine what is leaking and where. There are hundreds if not thousands of threads on this site alone dealing with vacuum systems.

3: The 240D has no power anyway! If it is loud, check for exhaust pipe holes, rotten flex pipe, blown exhaust manifold, etc. Same things you'd check on a gas engine. Oil pressure gauge should be between 1 and 2 at idle and peg when you step on the accelerator.

4: Again common. You may have a broken cable (common) or broken gear (less common).

5: Worn steering box, worn tie-rod ends, worn suspension bushings, etc. All of them are common. Start with the tie-rod ends and drag link (center link), if sloppy, replace. Check your shocks as well. A Mercedes should not bounce when you give it a firm push on a corner. If it bounces or the whole car wallows or jiggles, time for shocks. The shocks alone can make a HUGE difference in how the car handles and steers.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Does anyone know where I can find a vacuum diagram for the entire system to check for leaks??

Before you do the compression test adust the valves. Then after 200-300 miles adjust them again. The valve adjustment can also aid in starting and speed.

Have someone slowly step on the accelerator while you watch and see how much play there is in the linkages before the Throttle Lever on the Fuel Injection Pump starts moving.

My 300D was deadly slow accelerating but ran normal once it was up to speed. It turned out I had too much play in the thottle linkages. The linkages have specific lengths and the bell crank on the fire wall has parts that fall apart with age and use.

Someone will have to post the site but there is an internet accessable Mercedes Factory Service manual. There is also CD manual sets you can buy but you will need to find out what computer operating system it needs.

There is printed old printed Manuals on eBay you can bid on but they are divided up and the Engine is seperate from the Chassis manual and so on.
Repair Links also have how to do info.
Fast navigation http://www.peachparts.com/shopforum/diy-links-parts-category/146034-fast-navigation-do-yourself-links.html

The steering box ha an adjustment pictured. Loosening the larg Nut and turning the center screw counter clock wise tightens the adjustment. If after the adjustment you find ourself turning the wheel back and forth overcompensating it is too tight. If it is too tight it sort of sticks to the left and the right.

There is supposed to be some play; see the manual for how much.

See the posted repair links for the vacuum issue.

Attached Thumbnails

 

__________________
84 300D, 82 Volvo 244Gl Diesel

If the steering feels clunky and vague, it could also be the steering coupler between the steering wheel and the steering box.

http://www.peachparts.com/shopforum/vintage-mercedes/108536-w115-steering-coupling-finished.html

__________________
1968 220D, w115, /8, OM615, Automatic transmission.
My 1987 300TD wagon was sold and my 2003 W210 E320 wagon was totaled (sheds tear).

It is here

__________________
78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022

That much steering play check to make sure the frame the steering box mounts to has not rusted out.


Same chassis on the gas versions I had to repair a couple of them I owed years ago. I would suggest that it is not an uncommon problem on that chassis. Not technically a hard repair. Visually watch the steering box with someone turning the wheel from side to side.

Where do people buy most of their parts from including maintenance like oil and air filters?




1974 240D

Nice if you can support the site promoter. Free shipping I believe over 75.00 is or was on.