Already replaced CTS, Engine temperature needle still not moving

[hernandez3011]

--------------------------------------------------------------------------------

My engine temp meter/needle started acting up a few months ago. It would rise exactly halfway where it's supposed to be but sometimes move down (counter-clockwise). I did some research on this forum and figured it was probably my coolant temperature sensor (CTS). I replaced the CTS with a brand new one and the car continues to do the same thing..............I'll start the car and the needle usually doesn't even move, even after hours of driving. The weird thing is that is does move every week or so but never reaches the halfway point. It stays at about 10-11 o'clock position and then goes back down to the initial(car is off) position. Almost never reaches 12' o'clock. What other factors could be causing this? Any help is appreciated. Have heard it could be the thermostat also. BTW I am not getting any codes. Thanks

2001 A4 1.8TQMS 155k miles.
MBC, GIAC chip, test pipe, 710N DV,

[s42k5b]

is it erratic movement?

[B5A4Kevin]

erratic movement could be a sign of a faulty connection inside the cluster. you need to have an analog gauge sweep test performed on the cluster. see if you can have access to a vag scan tool (i dunno if you can do it on a laptop with ross-tech software), or a dealership you have good business with may check it for free.

it sounds to me however, that it could be a stuck open thermostat. i would replace this since it is a cheap component, and relatively easy repair, especially if it has not been replaced already.

you could also try covering half of the radiator with cardboard and see if this may raise the temps. just remember to remove it when spring comes around.

[GetBoosted84]

My temp gauge never hit 12 o'clock and it would fluxuate while driving. I replaced the thermostat and it fixed it. Car warms up much faster now and it hits 12 o'clock on the gauge every time.

I'm guessing that's the culprit.

[njm23]

thermostat most likely

[hernandez3011]

Thanks get boosted. I'm going to replace the thermostat. I'll keep this posted for other people who read this in the future ;-)

[matt_mcmhn]

I'm having the exact same problem, but I don't know how to replace the thermostat myself. Is there a reliable "how-to" on that? Or could someone post it?

[B5A4Kevin]

I'm having the exact same problem, but I don't know how to replace the thermostat myself. Is there a reliable "how-to" on that? Or could someone post it?

i cant find one on audidiy.com, but if you have a b5, it should be the hose coming from the radiator, routed under the intake manifold with 2 10mm/5mm allen bolts. the b6 ones have a larger housing with an electrical connector. b5's are conventional however. remove the bolts, lube new seal with coolant, place thermostat with bar in vertical position. tools that help incluide:

5mm ball allen socket with extension and
flex head ratchet

or

flex 10mm socket with extension and
normal or flex head ratchet

airlift kit (and source of compressed air)

electric or air tools (1/4" or 3/8" impact)

dont forget to drain the coolant first or catch it when unbolting thermostat. it has a bittering agent, but you dont want any animals or children trying to drink it.

[matt_mcmhn]

^^Thank you! I have a b5, I'll take a look at that and see if I can do it myself. It sounds like I can