engine cooling??

[Sugar79]

Hi everyone.. got a 2000 plate 2.0 mk4 golf

Problem I have with it is that the temp gauge reads the the engine is cold or slightly warm most of the time even when its been running/driving for 20mins or so..

ive had the car about 5months.. when I first got it it was doing this.. so i changed that temp sender, didn't improve things.. also not very much heat was coming through the heater.. so I thought must be a stuck open thermo.. had thermo changed ( I even tested the new thermo in a pan of hot water to make sure it worked.. which it did) car seems to get up to temp then.. sit nicely 90c.. for about a month.. now the temp gauge is doing the same thing.. except I have lovely heat through the vent.. i have water flow back in the bottle.. all water pipes are hot after a good run.. even the one with the temp sender is hot.. feels hotter than the read out on the dash?? engine runs lovely..

Could a new sender be faulty? or could the actual dash gauge be faulty? 

I was watching the gauge closely after a run earlier.. it was sitting at I suppose at about 60c.. it would move up n down very very slightly.. then I would drive off and it would drop by a millimeter.. its all rather odd.. I don't think there is a problem with the engine.. specially since I have really good heat now from the heater.. engine runs fine.. must be more electrical..

any ideas anyone?

thanks in advance

[Sugar79]

think i've put this in the wrong section?? 

[itavaltalainen]

still got the old temp sender?

if not you can check the new one with a multimeter (resistance mode).

i wrote this a while ago for the mk3 but it's the same procedure on a mk4 (resistance / temp curve is almost identical).
http://www.motor-talk.de/forum/aktion/Attachment.html?attachmentId=719242


the other possibility is a wiring issue or corrosion in the plug. corrosion in plug would be visible, if it's not visible you can try to see if you can get the gauge to show something using resistors (go to maplins and buy a 'grab' bag of them with different values). just bang it in the plug, turn ignition on and see what the gauge says (i would use approx 100 ohms, 1k, 1k8, 2k7, 4k8)