Son has bought a diesel Mondeo recently and is having a few problems.

The exhaust centre box was replaced recently but he is now getting some black smoke from the bsck end when accelerating. Some power loss is evident at the same time. Also when the engine is warmed up there is smoke/gaseous product coming from somewhere near the front of the engine. I cannot tell where from but it may be the dipstick or the inch diameter silver pipe covered with a heat shield. There is also a fluid in the hollows by what I presume are the injectors. It's clear and feels greasy so I expect it's diesel.

Very little experience with diesels so any help would be great!

It's clear and feels greasy so I expect it's diesel.

Well, it is likely to be either Diesel or engine oil (and, engine oil in diesels is usually dirty, so if it is clean that more-or-less rules that out), so it will be leaking there from somewhere.

The obvious is that it is leaking from the vicinity of the injectors, either the fuel feed to the injectors or the seal from the injectors to the cylinder head.

I'm a bit worried that you write this as if it is the same on all cylinders; is that presumption true? If it is, what could have caused this on all cylinders? (Previous owner doing something undesirable, maybe?)

Also when the engine is warmed up there is smoke/gaseous product coming from somewhere near the front of the engine.

If you are leaking a fluid (diesel, oil, whatever) somewhere, and it is getting to somewhere rather hot, this would probably be expected. So, check on leaks first.

The exhaust centre box was replaced recently but he is now getting some black smoke from the bsck end when accelerating.

Some - a little - smoke is to be expected when accelerating hard; lots isn't. It shouldn't be anything to do with the back box.

Do you have any warranty with the vehicle? Did you buy it from a garage?

Edit:

(Year/mileage/ model/engine would be helpful)

Excess diesel is the reason normally for black smoke, I had the issue when the intercooler pipe split, air was leaking out, the air fuel ratio was bad, and more fuel was going into the exhaust. I would leave a plume of smoke - like a 6 foot by 3 foot wide bowling ball in the middle of the road :p

Thanks for the replies, sorry for the delayed reply.

Following on from your suggestions I had a good look at the intercooler pipe and it had a 3.5 inch long split at the top. I ordered a silicon replacement from ebay. I've just changed it over and touch wood the missing and power loss has been fixed. The black smoke has reduced except under hard acceleration. I think this may be residual muck, well, hopefully and with a bit of luck it will cure itself . It also appears the fluid on top was misting from the split pipe.

Regards

Likely the egr is the remainder of the black smoke, you can clean it, you can blank it but you would probably get the engine management light Come to play.

Thanks, I'll get the toothbrush out!

I see there's some info on blanking, I'll give that some thought as well.

Yeah it's cheap and worth doing but the euro 4 engines bar the mk4 1.8 have issues and throw eml on when the plates installed...