Continuing from my previous question (here) one of the pistons have no combustion and so the car is only working with three pistons, and there is a sound like a piece of metal smacking against something.

There car is from 2006, and is diesel and has a mileage of 70k.

A new engine isn't very economical and labour intensive too! Can pistons be fixed?

Apparently, due to the piston going, oil got into the turbo too! So something has to be done about that too.

The car is in such good condition and it happened out of the blue, never had any issues in the last 4 years with it (since purchasing it). And I had it checked at two garages, one being the Peugeot dealer and they said that was the only issue with it, such a shame just to scrap it or sell it for peanuts.

Help pls.

  • Pistons can be replaced, but it is usually cheaper to replace the engine with a re manufactured or used unit.
    – Moab
    Jun 26, 2018 at 16:38

3 Answers 3


In this case you are probably not going to cut it with replacing broken parts, your engine needs to be overhauled. The faulty piston must be replaced but the cilinder walls are likely to be damaged too (hence the metal-on-metal sound). Also the cylinder head could be damaged. Depending on the pricing of a replacement engine, it could be cheaper to swap the engine than to pay for parts and labour for the overhaul. Go to a workshop (better to skip the dealer with a 12 year old car) and ask if they can say anything about a pricing indication for replacement or repair.


The labour to remove the old engine and fit a new replacement or a secondhand replacement or to be able to strip and rebuild is the same...

What you then add is the time to sort and tune the secondhand engine or the time to strip / rebuild your existing engine...

You need to check out the prices and time / parts availabilty etc One word of advice is to fit a set of pistons, not just one as they are usually closely matched...

  • So would replacing the 4 pistons be cheaper than just replacing the engine? And what about the turbo?
    – Mark
    Jun 26, 2018 at 16:46
  • Given my answer, X is the time to remove and refit the engine and Y is the time to strip and rebuild plus cost of parts... If you then think Z is cost of replacement engine then : X + Y = Z + X .. But how much time do you have and how long to source an engine and how long will it take you to strip and re-build making sure you have all the gaskets and seals necessary...
    – Solar Mike
    Jun 26, 2018 at 22:13
  • Can you do the same quality job as a mech? Also re turbo you need to explain more... a pcv system puts a small amount of oil mist into the air going through the turbo...
    – Solar Mike
    Jun 26, 2018 at 22:16

Replacing the single piston - essentially stripping the engine down and rebuilding it (replacing any damaged parts along the way) is probably possible.. but it's unlikely to be economically sensible.

The "metal smacking against something" sounds are worrying.. there could easily be significant damage being caused by that - the extent of which wouldn't be visible until the engine has been at least partially stripped down and at that point you could find yourself with a dismantled engine and the option to either bite the bullet and spend what it takes to get it running again or abandon the job and be left with a hefty bill for stripping it down and still have a broken car. I wouldn't recommend it in your scenario.

If yours is the 2.0 HDI engine though a straight swap for a secondhand unit may be feasible - the engine was used across multiple Peugeot and Citroën vehicles for a number of years and secondhand units are plentiful and pretty reasonably priced (at least in the UK where I am - eBay has many such units for ~ £300) and, assuming nothing is too badly corroded in place a competent mechanic with a well-equipped workshop should be able to do a straight swap in a few hours.

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