12 months ago, I bought a 1999 Mitsubishi Delica with a 4m40 2.8TD engine (diesel).

  • The vehicle itself has done 120,000 miles and runs very well.
  • There is a very slight oil leak somewhere.
  • There is no service history with the vehicle.

I bought the vehicle as I am looking at converting it into a campervan and going on a round-the-world adventure starting sometime next year. I recently acquired a fully stocked workshop/car garage for the next four months to concentrate on the conversion.


  • As I now have space, time, tools and physical help, is it wise/beneficial to pull the engine out and give it a complete overhaul?
  • If no overhaul is required, what would be your main concerns?

I have always done my own repairs and I can confidently say I can do the job, my main reason to ask is wondering is it really worth it?

My main worry would be any issues while on the road. Also, the timing chain as far as I am aware of has never been changed.

Thank you

  • 3
    Welcome to Motor Vehicle Maintenance & Repair! If it runs well, why rebuild it? Mitsubishi makes pretty good diesel engines IIRC. I mean, they have a whole fleet of trucks they make so have plenty of experience. Regardless of maintenance history, I'd expect the engine to last 300-400k easy. Fixing the oil leak is a no brainer, but a complete rebuild? IMHO, you'd most likely be wasting your money on an otherwise good engine. Commented Nov 21, 2020 at 22:45
  • Apart from air filter, oil and fuel filters, replacing or servicing the injectors could be good.
    – Solar Mike
    Commented Nov 22, 2020 at 4:29

1 Answer 1


No, you shouldn't rebuild the engine unless you have a specific reason. 120k miles isn't that much for a modern engine, so there's no reason to spend the effort, time and money to strip it down. Clean the engine so you find and fix any leaks, do a compression check and do any service items that are due or will become due on the trip like timing chains, tensioners, glow plugs, injectors, etc. Replace the belts unless they look really new.

  • I agree! Proactively rebuilding a properly running engine makes no sense here.
    – jwh20
    Commented Nov 22, 2020 at 17:41

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