Audi B4 1.9 tdi radiator removal
 

Since engine of my car never reaches ideal operating temperature I will most certainly have to change thermostat. So I will have to drain coolant... So since coolant is drained anyway, I will change both other temperature sensors... Since coolant is drained, why not remove radiator ... very easy to change timing belt... and other belts... well I have time, car only has to be ready by march...

I will start tonight, any hints are much appreciated!
Are there other things I should tackle while having rad & coolant out?

thx guys!

Just removed thermostat... looks fine...
Just removed and tested coolant temp sensor (blue one)... seems to be in working order. I tested sensor with Ohm meter at 20k and got good readings between hot and cold tested water. Does anyone know what reading I should get at a specific temperature? So I can find out if sensor is ok or not...

Might it give you better access to check the intercooler and pipework??
..........just an idea, I've never had the need to take out the radiator.

Just removed second coolant temp sensor. It is grey coloured and has 3 contacts... how do you test this one??? I get no reading at all with Ohm meter... seems pretty coroded on the inside.

Where on engine is it?

Hey John, it's on the back of the engine top side. here you have pics of both sensor. I must say gray sensor is pretty coroded on the inside on contacts...
Thermostat looks ok, I will change all contacts and thermostat anyway ...

step by step
 

here some pics of progress of the engine service works.
Removed top front of engine bay so I can take radiator out if I'm up to it.
Saw a red cap on bottom of inside radiator and I thought that this might be the drain for the radiator. No luck screwing this one out :) :D will have remaining bit on the inside removed by specialist that will clean and rinse the radiator.
then removed the hose from the thermostat... Thermostat looks in good working order and was surely closed up when I removed tube... had a nice shower of coolant removing the thermostat from its housing :nod: . The coolant on the inside was as new. That confirms last service the car had with it's previous owner in march this year. Invoice said they replaced coolant, so that is true :)
Then removed both coolant sensor so I can replace them both. Blue sensor seems ok, tested it with Ohm meter, from grey sensor I get no reading between the different contacts. I have new one already and will test new one with Ohm meter and see what the results are this afternoon.

I would think if you're getting an open circuit reading then it could be a switch for overheating warning light and buzzer maybe?
But if you're changing it anyway !........worry not.

You could try heating an appropriately sized torx bit and pushing it into the plastic (so it melts into it) and let it cool for a few minutes......then try unscrewing.

That is a very good Idea! I will try that John.
Radiator will be taken to a shop that is precialised in cleaning and fixing/rebuilding radiators or making custom radiators. If I don't get broken of plug out, they hopefully can... thx