1.9 dci no power and bluey grey smoke is coming from the exhaust

Fuel filter blocked ... had a look?

Is that mileage in miles or km. Either way that isn't bad for a 20 year old vehicle. You need to try and get a better look at the exhaust smoke's colour. Is it definitely Grey or is it more of a Blue?
Blue suggests the engine is burning engine oil so it might be worth getting the head gasket checked. Take a look in the coolant reservoir for oil floating on the top of the coolant and remove the oil filler cap to look for a 'mayonnaise' like build up.
Grey exhaust smoke suggests the engine exhaust system isn't breathing correctly so get the Crankcase Ventilation system checked.
You must also keep in mind older, higher mileage engines will have worn piston rings and cylinder bores so a very small amount of oil burning will be expected especially on a cold start up.
Read through the attached web site it might help.

https://motorcompanyleicester.co.uk/what-causes-grey-smoke-from-a-diesel-engine/

The heavy smoke is from all the fuel dumping in to the cylinders without enough heat. Can you plug the car in at might if not glow the plugs sevral times befor turning the engine over.key on few sec then off then on several times. Hope this atleast helps your cold start problem.

Hi, depends what colour black smoke, is it bluey black, grey black, whitey black, You may have to take it to a Diesel fuel shop, It may be the timing on the engine or the injector pump, (the pump may need to be timed to the engine, also the Injector pump also may need calibrating.) To calibrate pump you need to take it to a Diesel Fuel Workshop. Due to wear and conditions the injectore nozzles, injector pump, timing and performance of the engine will change over time.

You may have a broken ring or scored cylinder wall and piston. Have a cylinder leak down test performed to confirm this. Other causes can be a plugged crankcase ventilation system causing pressure to build in the engine, if that is the case the air cleaner box should have oil in it. The grey color of the smoke means you are burning a lot of oil.

White smoke from the exhaust indicates engine coolant entering the cylinders; usually caused by a blown head gasket or a cracked head. Continuing to run the engine will allow coolant to go through the engine internals and destroy them.

You likely have worn valve guides

this may be due to an oil leak getting onto the manifold or the manifold is cracked and exhaust gas is building up in the engine.

if smoke is intence and black this indicates oil.
if it is mid and grey blue this indicates exhaust gas


get checked by a mechanic


i hope this was useful.

Firstly, check the air filter and its piping, that there is not any restrictions. secondly, check, with the engine running, to see if any of the air intake hose are collapsing in on themselves, this would indicate a bad hose thats breaking inside and so , collapsing.
Hope this helps

What was the reason for thermostat replacement? Was it overheating? Are you losing coolant now? Is there oil in the radiator or water in the oil? The white/gray smoke could be a sign of head gasket problems.