Air Con and Temp

Mujnu

Mujnu

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Hi all,

I wanted to know if it's normal for my engine temp to drop a little when my heaters are on? This only happens when the car has reached full operating temp and I'm stationary. Also, if I'm stationary and my heaters are on the highest setting (before it has reached full temp) my car won't heat up until I lower it but if I am driving the car it will heat up fine regardless of air con on highest setting. Or is this a thermostat problem?

I hope that makes sense lol thanks
 
If it's a diesel engine, it will take longer to reach normal operating temperature when the car is static, especially in the winter. Coolant flows through the heater matrix without restriction of the thermostat so the heater matrix also acts as extra radiator for cooling the coolant. With a petrol engine it would be less noticeable.
 
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The gauge should be a solid 90 in vcds or a phone app, It might 87 or above anything below warrants a new stat.
 
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It's a 2006 diesel. The gauge sits bag on 90 when its fully warmed up as I had the thermostat changed when the timing belt was done 2 years ago. However, when my car is warming up and the heaters on highest setting its like the car stops heating up until I lower it, and when it's fully at 90 and I put the heaters on the temp will drop a few mm on the gauge.
 
Hmmm mines a diesel too and yes takes an age but never noticed the temp dropping when fully warmed up, if using the heaters
 
LEE69 said:
Hmmm mines a diesel too and yes takes an age but never noticed the temp dropping when fully warmed up, if using the heaters
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That's only when stationary, if I drive when the cars fully warmed up with heaters on the temp won't drop. I'm confused lol
 
Is weird maybe the stat is failing?
Maybe it will drop a touch as not as much heat being produced when stopped?
 
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Trust me when I say this BUT you need a new thermostat 100%.

My A3 was doing exactly the same last year until I had the thermostat changed and now the needle stays bang on 90 degrees once warmed up no matter what.

I have owned VAG cars for years and still have my Fabia vRS that I purchased brand new in 2004 and once warm the needle stays on 90 whatever you throw at it.

You will probably also notice (or not) that your MPG has increased too, that's another symptom.

So, 100% new thermostat.
 
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Carefree69 said:
Trust me when I say this BUT you need a new thermostat 100%.

My A3 was doing exactly the same last year until I had the thermostat changed and now the needle stays bang on 90 degrees once warmed up no matter what.

I have owned VAG cars for years and still have my Fabia vRS that I purchased brand new in 2004 and once warm the needle stays on 90 whatever you throw at it.

You will probably also notice (or not) that your MPG has increased too, that's another symptom.

So, 100% new thermostat.
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Would your car always stay on the 90 even if you put the heaters on (obviously in winter)? My car stays on 90 but at stationary when I put the heaters on the gauge drops a little. Also, I don't know if my mpg is good, I get 370miles to a tank all around town miles, I have a 1.9tdi, is that good or bad? Thanks
 
Hi sorry to hijack the thread Mujnu I recently getting a weird problem sometimes BKD's idles around 980-1000 (choke?) on when the car is at temperature and the heater is on happens when I am about to park it up.Anyone know what this could be? Is it a serious problem?
 
Qasim91 said:
Hi sorry to hijack the thread Mujnu I recently getting a weird problem sometimes BKD's idles around 980-1000 (choke?) on when the car is at temperature and the heater is on happens when I am about to park it up.Anyone know what this could be? Is it a serious problem?
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It's alright, I've heard some people say that a car may sometimes raise its revs to meet the demand of the car, so in your case maybe the car revs higher when you put the heater on so it is able to carry out the job?
 
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Mujnu said:
It's alright, I've heard some people say that a car may sometimes raise its revs to meet the demand of the car, so in your case maybe the car revs higher when you put the heater on so it is able to carry out the job?
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Thanks thats good to hear
 
What was the out come?Just had a similar issue today.Car was fully warmed up,then i parked up with the engine still running ,15 minutes later engine running at 80 degrees,must point out the outside temp was 3.5 degrees C.
 
ahtcap said:
What was the out come?Just had a similar issue today.Car was fully warmed up,then i parked up with the engine still running ,15 minutes later engine running at 80 degrees,must point out the outside temp was 3.5 degrees C.
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I just left mine as it is to be honest. It may be a dodgy thermostat but it's not really giving me a big problem so haven't really bothered with it.

Did you have your heaters on when the temp went down?


Sent from my iPhone using Tapatalk
 
You'll be losing mpg at the least if the gauge isn't staying at 90 all the time
 
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