Corolla E12 D4D warm start problem after engine overheating

[DieselPowerAddict]

Hello everyone, i am new to this forum and apologies if i am posting in the wrong section. Excuse my grammar and spelling by the way because i am from a french speaking country.

I own a 2004 Corolla hatchback D4D with 161k miles on the clock since 2016 and the car has been almost trouble free until 3 months ago when it started overheating and the radiator fan would not work. In two years of ownership the only parts i replaced are the brake pads. The problem is that i live in a part of the world where the mechanics are not very skilled . To solve the issue, one mechanic bypassed the normal temperature sensor-thermostat cooling system and connected the fan directly to the alternator so it would run non stop. This caused the engine to  run constantly cold and never reach its operating temperature( even after a 250 miles road trip with peaks at 160 km/h). The first consequence of that was a ridiculous fuel consumption which jumped to 17 mpg city and 40 mpg on the open road . The normal figures are 31 mpg in the city and 58 mpg on the open . A month later the Battery died, followed by two glow plugs which were replaced . I asked him to put everything back as it was before he bypassed the thermostat which he did but from that day the car was different. It used to start fine 24/7 but now it only does when cold ( the starter cranks 4 to 5 times before it does which is unusual) but when the engine reaches its operating temperature it does not . It behaves as if the Battery was weak. Every time it happens i have to wait 20 minutes for it to cool down before starting it again( it never fails to start when cold) . I ditched the first mechanic for another one who told me it could be the starter motor and said i need a stronger starter . Another one said there might be at least one leaky or dirty injector because there is a little bit too much black smoke coming out of the exhaust. Can anyone help me? I know this is a simple fix because the performance/engine noise is unchanged since day 1 but with so many incompetent mechanic around i prefer to hear from owners who had the same problem.

Cheers

DieselPowerAddict

[Colourd]

Possibly your problem could be the starter motor - I recall reading similar hot start stories

I believe there is an updated one available