W123 buyers advice would be lovely - 300TD 1979

[SamCritch]

W123 buyers advice anyone? 300TD 1979

Hi,


This weekend I'm planning to go and see a 1979 300TD that's for sale within an hour or so of where I live (in Amsterdam). It looks to be in good condition from the 3 photos on the website, and I'll be quizzing the owner about it in detail.

I used to own a W111 (1966 230S) and ran (and fixed) a Peugeot 305 diesel for several years, but I don't have any experience specific to this model or Mercedes diesels, so I could do with some tips for problems to look out for. Any volunteers?

I've been reading the forums and have come up with areas which seem commonly to be a problem. If you have any more, I'd be really interested in hearing about them. Here we go:

Engine, Transmission, Suspension
--------------------------------------

• - Watch out for worn timing chain
• - - Is wear visible? Or is the chain behind a cover?
• - - I will ask when it was last changed. What's the recommended interval?
• - Watch out for valve seals
• - - How do I detect wear here? White smoke?
• - Head gaskets - these go occasionally
• - Leaking joint between engine and injection pump
• - If the engine starts well from cold, then it's usual in good condition (?)
• - Warm idling ticking sound is common
• - - What does this signify?
• - Doesn't seem like smoke is a big problem with these engines
• - Watch out for corrosion around battery tray
• - Look out for smooth gear change with no slip
• - If rear suspension is stiff, hydraulic spheres may need replacing
• - Listen for worn out differential
• - - How to detect? Noise when cornering?

Bodywork, Interior etc
-------------------------

• - Most common places for rust
• - - Lower front arches
• - - Rear wheel arches
• - - Inner plastic wheel arch protectors (not sure what these will look like)
• - - Valances (lower front)
• - - Bottom of boot window and boot door
• - - - Open boot and look closely under window with a torch
• - - Sills
• - - Front wings (how to check inside?)
• - - Underneath
• - - Check bulkhead (how to access?)
• - - Around sunroof
• - Leaky sunroof
• - - Very common
• - - Usually caused by clocked drains (these run to the sills)
• - - Check for pipe corrosion if possible
• - Wet under front passenger carpet
• - - Usually blocked sunroof drains (again)
• - Driver's seat side-support cushion usually worn
• - Central locking often not working properly any more
• - - Usually down to broken/leaking vacuum hose somewhere
• - - Vacuum comes from manifold
• - Headlight adjusters
• - - Again, usually vacuum-related again
• - Economy gauge
• - - Again, usually vacuum-related
• - Seat belts - rear seats and seats 6 & 7 sometimes stuck

Electrics
---------

• - No one seems to have a problem with these!

Anything else?

Many thanks in advance,

Sam

 

[Froddan]

Vacuum related, central locking usually runs out of pressure in a day or so. Can still open the door but it won't open all of them, until engine is started.