Mk1 Diesel cooling problems...

Hi, i've got cooling problems on my 82 1.6 diesel golf.
Has been running fine for 6 months but always cool, I thought it was just the thermostat jammed.
Since this bloody cold weather though, It just started to over heat like crazy.
Once it cools down and re-filled with coolant it's ok again.
Went to change the thermostat yesterday and realized it was missing one?
Banged one in and hey presto, we have temperature and a working heater.
It'll hover around midway but as soon as you start to give the beans it shoots through the roof.
I'm noticing that the fan isn't coming on, but the area it's located at the bottom of the radiator is cold.I'm starting to think that maybe there is a blockage in my radiator.

Cant quite work it out!

Overheating in freezing weather is a sign of lack of anti freeze. The water freezes in the rad and so the coolant can't circulate and boils up around the engine block.

Although in this instance the lack of a thermostat looks like someone has had over heating problems previously. Years ago when I had a '81 Diesel Jetta it suffered from a cracked cylinder head. It would run OK up to 40-50mph but anything above would cause it to boil up. This was not an unknown problem on the early VW Diesels.

Its probably a blocked rad or a it could be the water pump.
If it hasnt been changed chances it needs too be.

Stick a couple of pics of the ol girl mate.

Cheers

Engines no spring chicken, done almost 200k and has had 16 owners.
Never leaks any coolant from anywhere, the oil and coolant are clean.
There's plenty of anti-freeze in there now, might take the stat out and
refill it with 50/50 if a radiator flush doesn't cure it.

Not much to look at, but gets plenty of looks never the less

Nice,

Remember seeing this a few years ago.

Was owned by one of our fellow club members.

Well whatever it is, I couldn't get it to run with the stat in. Flushed the whole system, back flushed the rad and still too much heat. Hot wired the fan up and still the same.

It's back without a stat and sits at the top of the cool-zone, never rises more than about 3/5 of the way, even in traffic. 200k birthday is looming so I guess I can't expect to much. It's probably happy to be running on diesel in this cold as well.