engine temp/ heating/ thermostat?

[gr2uk]

hi, all new to this so have no idea if im posting in the correct place. anyways been having an issue since i bought my 2006 A4 cab 2.0 tdi a couple of months ago, seems others are having similar issues but mine is like this- engine rarely gets to temp ususally sits around 70 during driving , occasionally will hit 90 but never goes over. it will drop down when doing anything more than walking pace. ive never heard the fan kick in even when it does hit 90. heat from the vents is strange too - i get luke warm air on any setting other than ‘hi’ when i might get 2 minutes of ok heat before that drops off to cool air again. seems to warm up when revved.

i have changed the coolant as it looked a light brown colour and didnt smell the best. now its nice and pink and has been since i chamgee it a month ago. the pipe coming from the expansion tank was blocked with what i can only describe as like frogspawn with some metallicy bits in it possibly radweld in the system? had to use a screwdriver in the bottom of the tank to break that up. ive flushed the matrix as suggested by other posters , got some more crud out before a nice clear flow. was thinking stat stuck open? possibly stat or something else also blocked up
with the same stuff that was in the tank? im not losing any coolant and bled air through the top pipe to the matrix,

sorry for long post i think the plan is change stat. can i remove the stat and check it quickly without removing belts and alternatior? it looks like i can get to it by pulling some wires out of the way??

[Rob69]

Just change the stat, don't bother testing it, I had similar cool running problems as you and my stat tested ok, but a new stat made a big difference, engine came up to temp quickly and stayed there.

[gr2uk]

Just change the stat, don't bother testing it, I had similar cool running problems as you and my stat tested ok, but a new stat made a big difference, engine came up to temp quickly and stayed there.

ok thats what i thought thanks. there are two different types listed on ecp any idea which one i need?

[Rob69]

get an OEM stat from dealer, TPS or genuine parts supplier, don't bother with ECP, you'll likely end up with the wrong part.

[gr2uk]

just incase anyone else was interested, part from ecp was fine, fitted without removing alternator , although very tight. engine now up to temp within a few miles and stays there, massive improvement in mpg - hasnt entirey cured the cabin heat problem but has made a noticeable difference