Temp Gauge Goes down while driving.

[2013R]

OP, I have always said "This is NOT a cold weather car". And thats very true.

What you have described is NORMAL! I see it all the time!

yes. its normal. but not a terrible idea to replace the thermostat just in case.

 

[Tsi7]

In what world is this normal? Have any of you ever driven a tdi? I have, I owned a mk4 diesel which was so efficient at retaining heat that my coolant would take a long time to get to temp when it was very cold. When it did, it would only go down rapidly if I had the heat on high while i was idling, but while driving, especially on the highway at higher rpm, it wouldn't go down... it had to be extremely cold, and even then it would maintain coolant around 80-85 degrees Celsius (not the optimal temp of around 90 but still)

This is a gas engine, there is absolutely zero reason for the coolant temp to be dropping so drastically, especially in the scenario and temperature that the OP is describing

OP, just do what I mentioned and report back. If your coolant is indeed dropping in temp so drastically then I'll stand corrected, and i'll also be really surprised and confused as to what could be going on

 

[Juggar]

In what world is this normal? Have any of you ever driven a tdi? I have, I owned a mk4 diesel which was so efficient at retaining heat that my coolant would take a long time to get to temp when it was very cold. When it did, it would only go down rapidly if I had the heat on high while i was idling, but while driving, especially on the highway at higher rpm, it wouldn't go down... it had to be extremely cold, and even then it would maintain coolant around 80-85 degrees Celsius (not the optimal temp of around 90 but still)

This is a gas engine, there is absolutely zero reason for the coolant temp to be dropping so drastically, especially in the scenario and temperature that the OP is describing

OP, just do what I mentioned and report back. If your coolant is indeed dropping in temp so drastically then I'll stand corrected, and i'll also be really surprised and confused as to what could be going on

If I get on a highway then sure, of course it does not drop.

Under specific scenarios it CAN go down, such as ive described above. Not "drastically" but say, down to 175F which shows up a few ticks to the left of middle gauge.

Is totally normal. The heater core is a mini radiator and if you crank the heat when the engine has just got to the middle mark of the temp gauge and you are putting around at 35 mph, then yeah, it can go slightly down.

Bring any of your MK7 GTI's to my house and ill prove it to you on a cold morning.

 

[THEREALVRT]

I Did this today when it happend. The video is with the heat off.

It was about 12C. which is 53F

Ya, at 12c this shouldn't happen IMO, but maybe I am wrong i rarely run my heat at 12c outside temp

 

[Tsi7]

If I get on a highway then sure, of course it does not drop.

Under specific scenarios it CAN go down, such as ive described above. Not "drastically" but say, down to 175F which shows up a few ticks to the left of middle gauge.

Is totally normal. The heater core is a mini radiator and if you crank the heat when the engine has just got to the middle mark of the temp gauge and you are putting around at 35 mph, then yeah, it can go slightly down.

Bring any of your MK7 GTI's to my house and ill prove it to you on a cold morning.

When the engine has just got to the middle mark, it usually isn't at 90 degrees... I don't know how the mk7 is, but on my mk4, when the needle was in the middle (aka showing 90 degrees) it really could've been anywhere from 74 degrees to 97 degrees.... so if the mk7 does the same, then when your needle just gets to the middle and then you crank the heat, of course the temp may drop slightly when you're idling or maybe slow cruise at very low rpm in VERY cold temperature, but it won't stay low for very long (at least it shouldn't if everything is working properly)

I live in Canada, I know what cold is. My mk7 coolant needle was sticking bang on in the middle even while idling with heat on high when it was -25 degrees Celsius last winter

Like I said, in OPs case, something is more then likely not working properly

 

[Juggar]

When the engine has just got to the middle mark, it usually isn't at 90 degrees... I don't know how the mk7 is, but on my mk4, when the needle was in the middle (aka showing 90 degrees) it really could've been anywhere from 74 degrees to 97 degrees.... so if the mk7 does the same, then when your needle just gets to the middle and then you crank the heat, of course the temp may drop slightly when you're idling or maybe slow cruise at very low rpm in VERY cold temperature, but it won't stay low for very long (at least it shouldn't if everything is working properly)

I live in Canada, I know what cold is. My mk7 coolant needle was sticking bang on in the middle even while idling with heat on high when it was -25 degrees Celsius last winter

Like I said, in OPs case, something is more then likely not working properly

Yes, we know the coolant gauge is a semi-dummy gauge and that adds to the issue some as well. It can make the situation look worse than it is.

OP is fine, just the nature of 4 bangers with large radiators.

 

[Tsi7]

Yes, we know the coolant gauge is a semi-dummy gauge and that adds to the issue some as well. It can make the situation look worse than it is.

OP is fine, just the nature of 4 bangers with large radiators.

Lol

OP just do what I said, it's easy and doesn't cost you anything except a little bit of your time

 

[Reaper1]

Thanks for all the advice guys.

I tried checking the coolant with obdeleven and when the needle went down The app was showing the same.

Sent from my SM-G955F using Tapatalk

 

[Juggar]

Thanks for all the advice guys.

I tried checking the coolant with obdeleven and when the needle went down The app was showing the same.

Sent from my SM-G955F using Tapatalk

You know you dont need to use that app just to check coolant temp right?

use the performance gauges in the infotainment and you can get a digital coolant readout.

 

[Tsi7]

You know you dont need to use that app just to check coolant temp right?

use the performance gauges in the infotainment and you can get a digital coolant readout.

Who said the OP has a GTI?

Anyways, looks like you got your answer OP...more then likely a faulty coolant temp sensor is the culprit here and your situation was not normal like some have mentioned...

 

[Wrath And Tears]

You know you dont need to use that app just to check coolant temp right?

use the performance gauges in the infotainment and you can get a digital coolant readout.

That digital gauge is also a dummy gauge.

 

[Tsi7]

That digital gauge is also a dummy gauge.

lol, i was wondering if it was, but wasn't sure so didn't want to say so

 

[Juggar]

That digital gauge is also a dummy gauge.

Are you sure? The temps it provides seem reasonable and true.

 

[Wrath And Tears]

Are you sure? The temps it provides seem reasonable and true.

It's never matched my scan data, pretty much just sits at 192. Could be they changed the programming for it at some point.

 

[Diggs24]

They are dummy gauges on all cars to prevent people from freaking out if it moves around. Just like the gas tank still has gas when the gauge hits E. All about lowest common denominator.