why is my temp gauge at C when i drive?

[wrX2104]

i was driving back home from work and noticed that as i drive my temp gauge is at c instead of maybe a quarter of the way up like normal, but if im just stopped with the car on it raises almost half way up. is this normal? because driving with a cold engine to me is pretty dumb. any help?

[walky_talky20]

Could be either a bad coolant temp sensor, or (more likely) a bad thermostat. Neither are very expensive or hard to change. There are diy's and countless threads about this problem and the replacement of the aforementioned items. Good Luck.

[Dallas09]

If it raises when stopped it should be your thermostat. Coolant sensor is a possibility but more likely I think if you had the issue all the time and not just when sitting.

[wrX2104]

okay thanks, also where is normal oil temperature because my oil temp gauge reads pretty low..like one notch above the lowest point.

[walky_talky20]

Full operating temp for the oil is a touch over 200F (the third mark). If your coolant stays cold due to a bad thermostat, the oil will stay cold as well because we have a water to oil cooler. That is a good indication that your problem is indeed the thermostat. Because the coolant is *actually* staying cold, not just a faulty sensor.

[wrX2104]

how much will a new thermostat run me? and another thing, does every mechanic shop have vag-com cause i have a CEL too and its give the codes p0420 and p0300, but from my understanding they arent specific enough to detail what exactly is the problem..can anyone give me a diagnosis on these codes or do i have to use vag-com?

[twinpop171]

Full operating temp for the oil is a touch over 200F (the third mark). If your coolant stays cold due to a bad thermostat, the oil will stay cold as well because we have a water to oil cooler. That is a good indication that your problem is indeed the thermostat. Because the coolant is *actually* staying cold, not just a faulty sensor.

Good to know. I have the same situation with my car and I recently replaced the CTS. I guess that is why there is a lot of black soot in the tail pipe since the car is running too cold? Both O2s replaced as well with HFC BTW too. I thought that my oil temp guage was malfunctioning because it hardly moves.

[revolution337]

how much will a new thermostat run me? and another thing, does every mechanic shop have vag-com cause i have a CEL too and its give the codes p0420 and p0300, but from my understanding they arent specific enough to detail what exactly is the problem..can anyone give me a diagnosis on these codes or do i have to use vag-com?

thermostat from the dealer is like $25, not to hard to replace either,

[mdanish]

i was driving back home from work and noticed that as i drive my temp gauge is at c instead of maybe a quarter of the way up like normal, but if im just stopped with the car on it raises almost half way up. is this normal? because driving with a cold engine to me is pretty dumb. any help?

I noticed i have the exact same problem. Oil mark on cluster is one notch above the lowest point, even though I did an oil change a week ago. and my temp gauge stays all the way on cold, doesnt go up at all
..

[J Ozzie]

Yeaaa, mine just started this.. Goin up hill starts to warm up as well as the oil, Going down hill it cools right off and both are at the 1st notch. Good to know Thanks!