E46 Engine Temp

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Location
Chicago, IL
#1
Hey guys,

So Chicago's been in a deep freeze now for a couple of weeks. We've struggled to crack freezing for what seems like 2 weeks now, and last week we were seeing highs struggle to hit single digits and lows well below 0. I work in the suburbs and have been taking my old E46 out during this time because I wanted to spare my new ride from the ridiculously salted roads, but have noticed that the engine/oil temp has never warmed to its usual point (half-way between the blue and red indicators), and has struggled to warm up the interior as well (hot air never comes out, it only gets somewhat warm). The oil temp gauge consistently hovered just above the blue or cold portion of the gauge, even as the car was being driven at highway speeds for almost and hour. Even with yesterday's relatively mild 30 degrees, the car still didnt keep as warm as it did in the past, but was warmer than during the cold snap. I did add some additional anti-freeze to it before I started driving it again, but I wonder if I maybe added too much, or do you think the sub-zero temps that are keeping the engine so cold, which I have a hard time believing given the length and speeds at which I was driving for most of the time. Additionally, I found it strange the temperature gauge seemed to rise when the car was at idle vs. being driven? Did not notice this issue when I was driving the 335 last night. Any thoughts/ideas what my 323i is staying so cold???
 
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4,917
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18
Location
Reading,PA
#2
Most probable cause to eliminate first would be a bad thermostat. When they get tired, they can fail to close completely, allowing water to circulate through the radiator continuously. Therefore the car never gets up to temperature in cold weather.

I have not had this happen on a bimmer, but I have had this on other vehicles over the years.
 
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5
Location
Toronto, Canada
#3
That's exactly what a wide open thermostat feels like. It's just as cold here, and I had this problem with my e34 last year. Driving at highway speeds makes no difference as far as warming up an engine with a bad thermostat.

When the car sits at idle, the coolant will heat up a bit easier because 1) the fan clutch isn't turning as fast, 2) cold air isn't being forced through the radiator at high speed, and 3) the water pump isn't circulating the cooler fluid through the engine as fast.

Cheap and simple fix, and you'll have a warm cabin again!
 
Messages
246
Likes
0
Location
Chicago, IL
#4
Yep good call, guys. Thats gotta be it then. Thanks for the tip. The thermostat is relatively cheap, but I think it might be a pain to take the fan off the engine block and get to it. Will give it a shot and if I cant get in there, might end up taking it to my local shop. Thanks again.
 


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