What happens also is i'll be driving and the needle will rise and i'll stop and it will go up even further and then when I'm off again it goes back down, this normal? The needle is never still, it seems like it's always going up or down.

I feel like this didn't happen before, but it is hot, was 107 the other day. The radiator was professionally cleaned, the thermostat is new and the coolant cap is new also. Is this just me? I'm hoping I can blame this on the hot temperatures.

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2007 BMW 328XI

Probably just the ambient temperature, there's only so much your cooling system can do in 107 degree weather. Sitting still there isn't as much air moving through the radiator.

It does sound like your fan clutch needs attention from what you describe, although the ambient temp. could do what you are seeing.

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http://i106.photobucket.com/albums/m...73378_30-1.jpg

It is pretty normal though, to answer your question.

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http://i106.photobucket.com/albums/m...73378_30-1.jpg

MB chose not to damp the temp response in the gage. As a result, you see the temp gage moving around at a greater rate than other cars.

It's normal to see it rise from cold position to it's normal position and it should remain fairly stable under steady state, flat driving. It's normal to see a rise when climbing a hill or while stopped and idling.

Jim

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14 E250 BlueTEC black. 45k miles
95 E320 Cabriolet Emerald green 66k miles
94 E320 Cabriolet Emerald green 152k miles
85 300TD 4 spd man, euro bumpers and lights, 15" Pentas dark blue 274k miles

something similar happened to me at some lower ambient temps. turned out to be air still in the system that needed to be burped. could be?

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1985 300D - 1984 Euro 280E AMG Clone (SOLD) - 1978 280CE (SOLD) - 1983 300D (SOLD) - 1981 300D (SOLD)

At 107 ambient, it's normal operation. All cars do the same thing. Just that most cars, particularly Japanese models, have an "idiot guage" that points dead center for every engine temperature from just above cold to just below boiling over, and people have become conditioned by such things.

Think about all the variables which influence the rate at which heat is added to and removed from the cooling system. Added heat is proportional to how much throttle is being used. Removed heat is influenced by airflow over the radiator (ie vehicle speed) and coolant flow, which is proportional to engine RPM. Only if you could keep all these factors in relation, then engine temp would remain constant.

Something similar happened to me as Squabble. I had air in my cooling system, and my needle would jump around a little bit once warmed up. Once I got it out (parking on an incline, squeezing upper radiator hose, etc), my temp needle stays fairly smooth.
Not as smooth as other newer cars, but not quickly jumping like before. I was afraid I was going to have to replace the temp sender, clean the needle gears, etc.
A rare instance where repair was easier than thought...

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Mine moves around as well. Our Temp guages are "Plateaued", meaning they will rise to a certain point and then not go any higher until the temperature actually reaches 120celcius. I read the reasoning was to keep from distracting drivers when the temp might be approaching 110 celcius which is still a safe temperature

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Dennis
2006 E320 CDI Black/Black Leather. Nav, HTD Seats HK stereo 32000 miles.
2000 VW Passat 1.8t 300,000 miles as of Dec 09, 2009 original owner
1997 E300d Silver 300,000 miles As of Jan 05, 2010
3rd owner SOLD

Ok cool, thanks everyone. I imagine it should be fine, just this heat is way over the top! lol

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2007 BMW 328XI

That bothers me. I want to know what's going on and exactly how it's going on, and I can make my own interpretations of it. I can even decide whether or not to "worry" about it but I want the facts.

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~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL

It happens to me almost every day. Pulling out from home on way to work, one mile away, outside temp in the 80's, temp needle jumps to 120* mark.

I know my engine isn't hot yet. Few miles further down, I hit the dash above temp gauge, the needle returns to where it is supposed to be (87* mark) and stays there.

When ambient temp is in the 100's, temp needle stays solid at the 87* mark all day. Whats going on here?

I'll try burping the system with car parked on an incline.

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1987 300SDL 314K mi, counting; #22 Head
1999 E300Turbo 405K original miles
1997 E320 180K mi (Son's)
2002 ML320 (Son's)
1998 S320 140K mi (Son's) sold
1985 300SD 311K mi
1984 300D 324K mi (killed by a hit-n-run turd)
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