Recently, my 1.8T has not been getting up to the same temperature that it usually does. In the summer, the gauge stayed at about a half, but as the weather has gotten cooler, it only reaches about a quarter. Also, my gas milage has decreased by about 3mpg recently. Is this all normal for the cold weather??

 

Could be thermostat or temperature sensor.

 

is it stays at the quarter after a long drive ? you might need a new temp. sensor which is about $5-$10 bucks at ecstuning.com

 

Yeah, new thermostat is a must. That's one of the things I always change no matter what when I pick up a used vehicle, or every other year.

Selling engines, I've had too many customers overheat and blow something... because they had a bad thermostat!

I also recommend regular radiator flushing and flow testing in your cooling system.

 

I would say normal.

In the winter time, mine stays below 1/4. In the summer, its a little over the 1/4 mark if moving, and will get up to 1/2 way if its sitting for a few on a hot day. It never goes over 1/2.

So, as long as this is the case, no need to worry about anything. You car is running a little cooler cause its colder out side.

But, does it stay at 1/2 while driving in the summer? If it varies this much, you may want to check the coolant level and make sure the mix of coolant to water is proper.

I dont think it would be the themostat, its either open or closed. It could be the temp sensor, but I would bet either the coolant is low or not mixed properly.

 

Replace the t-stat. and temp sensor, cheap... The engine should always warm up to a certain temp which is the half way mark on the gauge (left of gas gauge). It should reach normal operating temps after 5-10mins of driving. If you are talking about your oil temp gauge (bottom left or rpm's), that is normal to flucutate between 1/4 and half way mark depening on the season/outside temp.

 

My temp guage is different summer vs winter.

Not by a lot, but i just did the t-belt this summer, and flushed system and all that, and it still does it.
Just under a quarter in winter, just over in summer.

knowing that I replaced everything except the sensor, I am not worried.

Like you said, it cant hurt to replace sensor and thermo, cause they are cheap.

 

I have a similar problem with my 95 1.8t. After a drive on the open road my temp drops to 60deg on the gauge..... any ideas?

 

uh yeah, all the stuff they posted BEFORE you lol.

 

alright thanks a lot. I'll probably try flushing the cooling system and re-filling it. I think my car is similar to aceturbo's in that it normally runs warmer in the summer than winter because just by running my hand over the engine bay after a drive during both conditions, I can definitelty feel a distinct difference in temp. But, the car does stay at a half in the summer and a quarter during the winter, unlike Aceturbo's whos car doesnt vary that much. Also, if the car idles even just for a minute in the cold the temp gauge goes up to a half and then when I start moving again, it goes back down to a quarter.