TDI VW Golf 3: Smoking Exhaust & Overheating Issues

I'm having the following problem. My Golf 3 is emitting black smoke from the exhaust and isn't running properly. It struggles to accelerate in first gear, pulling slowly. From second gear onwards, the performance is moderate. I recently replaced the radiator with a thermostat switch, and since then, it hasn't been working correctly. After driving for a short distance, coolant sprays out excessively from the coolant reservoir cap (when you open it).
I only drove for a very short distance, about 100 meters, without the cooler running.
Can you tell me what might be causing this?
Best regards.
Flo.

The engine is overheating and producing black smoke!

Faulty nozzles!

Regards,

Manuel.

I only drove for a very short distance, about 100 meters, without the cooler running.
Can you tell me what might be causing this?


Counter-question: Do you even know what you did?

I only drove for a very short distance, about 100 meters, without the cooler running.
Can you tell me what might be causing this?


Counter question: Do you even know what you did there?

Nothing really bad! Opening the expansion tank was much worse!

Regards,

Manuel.

Hi Flo,

The error likely only started occurring after the radiator was replaced; at least, that's how it seems.
Are you sure everything is connected correctly? Please double-check it.
Are both cooling circuits being addressed? After a drive, all the radiator hoses should be roughly the same temperature. If this is not the case, the control valve will malfunction. Did you also properly bleed the cooling circuit? The engine code (MKB) would also be helpful.

@ Manuel Thomas

My coolant temperature has been significantly lower than usual since last year (now only around 75-80 degrees Celsius, whereas it used to be consistently 90 degrees).
Do you think it could be related to the injectors (still the original ones on the 1Z)?

I actually suspect the thermostat more. However, I haven't done anything about it yet.

D. wrote:

@ Manuel Thomas My coolant temperature has been significantly lower than usual since last year (now only around 75-80 degrees Celsius, whereas it used to be consistently 90 degrees). Do you think it could be related to the injectors (still the original ones on the 1Z)? I would have suspected the thermostat more,

but I haven't done anything about it so far.

Are you guys now bread roll bakers or something?
Fuel injectors nenene.

Just install a new thermostat and that should fix it.

@flo__911

I can't make sense of this description.
What exactly was exchanged, and why? [/quote]

Sorry!!! - I'm embarrassed now.