Temperature gauge not in the middle

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DC_BS
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Temperature gauge not in the middle

Post by DC_BS »

Recently when the engine has been warmed up (driven for at least 30 minutes) I've noticed the engine temperature gauge needle is not exactly in the middle. If doing long motorway drives it occasionally goes into the middle but then drops down a couple of cm to just below the centre mark. Is this normal? I mean its not overheating but why does it not settle and stay in the exact middle of the gauge?
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alexperkins
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Re: Temperature gauge not in the middle

Post by alexperkins »

Temperature sensor is probably faulty - very common

Also possible the thermostat and thermostat housing has had it and the water is struggling to stay at temperature
TRiBaL
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Re: Temperature gauge not in the middle

Post by TRiBaL »

In my case, usually the temperature needle is in the middle but sometimes it drops just a bit (lets say 1' if it was a clock) while driving in very high speeds or in traffic. Soon after that it returns back to 90. My mechanic says it is normal. (my temp sensor is new, never changed the thermostat though)
DC_BS
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Re: Temperature gauge not in the middle

Post by DC_BS »

Is it easy to change the temperature sensor? And how pivotal is it to the operation of the vehicle?

Yeah it does go in the middle (usually in the 4 o'clock position) but never goes above.
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alexperkins
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Re: Temperature gauge not in the middle

Post by alexperkins »

Easy enough. There's a guide in the diy guides section

Pinnacle - can affect starting fuelling and various other operations
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Re: Temperature gauge not in the middle

Post by DC_BS »

I'm not sure if this video relates to the same model as mine, but it looks similar:

https://www.youtube.com/watch?v=Vv8kWL26U9w

Surely a warning light would have come on if there was a severe problem with the temperature sensor? I've done 110 miles in it on a full tank. Also don't know if its normal for the fuel needle to still be in the same position when I left the petrol station and it was all the way to the top.
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alexperkins
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Re: Temperature gauge not in the middle

Post by alexperkins »

No, it often fails with no warnings

110 miles to a full tank - surely that's a mistype?!

The fuel gauge on these is notoriously inaccurate for the full to 3/4 section. Normally corrects itself beneath 3/4
DC_BS
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Re: Temperature gauge not in the middle

Post by DC_BS »

Well as I mentioned earlier it does go in the middle once I've been driving for about 20-30 minutes, then goes slightly below the middle for a lot of the journey.

Filled it up on Friday and reset the journey counter to 0. Driven 110 miles and the fuel gauge hasn't moved that much.
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alexperkins
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Re: Temperature gauge not in the middle

Post by alexperkins »

Fuel gauge sounds normal then

As for temp, could be the sign of a faulty sender or thermostat then but I don't think it's an immediate concern
DC_BS
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Re: Temperature gauge not in the middle

Post by DC_BS »

Previous owner said he got 600 miles from a full tank, I never let it go down to when the warning light comes on though.

It hasn't quite been right ever since I got it back from the Autocentre that did the tyres/clutch, have they tampered with something else I wonder! Just don't know why exactly it drops below the normal (70?) mark when engine has been warmed up and the needle has touched the middle mark for a bit. If it was faulty it wouldn't touch it at all in the first place?
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alexperkins
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Re: Temperature gauge not in the middle

Post by alexperkins »

90 is the middle temperature

The gauge can swing up and down, rise then fall, be a little off or not work at all. Very much depends what it's reporting
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Re: Temperature gauge not in the middle

Post by DC_BS »

Sorry my mistake, 70 is the marker below that, I would say the needle sits around 85 if its just below the 90 indicator.
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Re: Temperature gauge not in the middle

Post by TRiBaL »

I am having the same thing, which at first thought was "normal" as my mechanic said, but now it got worse. When in traffic or speeding, the temperature needle may drop down even to 75 degrees. Then, after i slow down and keep revs around 2000-2500rpms it reaches 90 but struggles to stay there if i don't stay conservative in my driving. I am suspecting my thermostat does not fully close, it must be on it's way out. This started out earlier in spring but is very pronounced now. (note that my CTS is new).
i bought a new oem thermostat off e-bay earlier last year (as a precaution), in its original box, it looks fine but production year is 2005. I am not too sure if i should use that or get a new one from my local dealer??
I also purchased 2 new O-rings from VW as shown here (part 15): http://www.vagcat.com/epc/cat/vw/PO/200 ... 9/3010783/
Again, I don't know if it's really necessary to replace the second one (near the engine block side)as there is more job involved to remove the whole housing, but i am planning to keep the car. The other one will and should be replaced.
Any thoughts or suggestions are welcome.
DC_BS
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Re: Temperature gauge not in the middle

Post by DC_BS »

Yeah it only ever goes bang in the middle when I'm in traffic and the car has been driven for over 30 minutes. If on the motorway for 10 minutes or so it'll drop below that, but never below 70 though. I'm thinking I may have the same problem but I'm not sure.

This is how it shows after about 8 miles driving:

Image
TRiBaL
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Re: Temperature gauge not in the middle

Post by TRiBaL »

Yep! That's what i'm talking about.
I'm pretty sure it's the stat mate.
i'll probably put in the one i got (shelf life shouldn't be an issue on those, i suppose) along with the new o-ring and see how it goes from there.
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