[Reflex_nl]

Hi all,

About 8 months ago I bought a well-equipped pre-owned BMW 330i from 2006 with Sport pack and approx. 42k miles. It's a great car and I like to drive it :-). Still I don't like the fact that the car doesn’t have an engine temp gauge. This makes it hard to diagnose if something is wrong. I live in TX and after parking the car in my garage the air temperature in the garage rapidly increases (due to the car's heat). I probed the outside temp of the engine (on a typically day with 75 F air temp) and when opening the hood I pointed the gauge underneath the red circle in the picture. After parking the car it tops out at approx. 88 deg. Celsius. ~ 190 deg. Fahrenheit. This high to me because inside the engine it is probably even hotter.

Could you tell me whether this is normal or a deviation from the standard 330i engine running temp? Can you recommend other areas to probe or take a trip to the BMW garage…?

Thanks,

Reflex

[clark192]

You pointed the gauge at the oil filter housing, just curious if that matters.

There actually is a way, so I have read, to find out the engine temp of the car. The OBC has hidden menus which you can access through the dash, and one of the readouts is in fact the coolant temps.

http://e90.wetpaint.com/page/BC+hidden+menus?t=anon

Scroll down to where it says coolant temp, and give that a shot one day to see what it reads. I would expect the coolant level to be around 90C while being operated. I should check today, since I also live in a very warm place and I will let you know what my temps look like after the car is warmed up.

[Reflex_nl]

aha, thanks for mentioning. I have not seen the hidden menu, but I'm sure I will try it out! Please share your temp readings.

Thanks,

Reflex

BTW: the turbo engines (335i) do have an engine temp gauge that sits at approx 230 F after driving on highways.

[clark192]

Yea I know, and it sucks that we dont get one. But I dont think you can compare the engine temps of a 335i to us NA guys, not sure on that one.

So I checked, and we only get the coolant temp, which is a decent approximation of the oil temps. Here is what I found:

Cold start, engine is at around 50C. It takes about 8 minutes of easy driving to bring the coolant temp up to around 87C, which is when I hit the highway. Highway cruising takes the temps up to 90-95C, depending on throttle, etc. Cruising at a constant 70, the temps were reading around 91C, and then when parked in stop and go traffic, the temps hit a high of 96C. After sitting in a garage for around 2 hours at lunchtime (ambient temps today were like 38C) the coolant was at 74C. Took all of 2 minutes to get back up to the 90s and thats how the temp cycle goes for my 325i.

So it seems that the normal operating temp is around 200F for my engine, with an ambient temp of 100F. Hope that helps.

[Bartman619]

Originally Posted by clark192

Yea I know, and it sucks that we dont get one. But I dont think you can compare the engine temps of a 335i to us NA guys, not sure on that one.

So I checked, and we only get the coolant temp, which is a decent approximation of the oil temps. Here is what I found:

Cold start, engine is at around 50C. It takes about 8 minutes of easy driving to bring the coolant temp up to around 87C, which is when I hit the highway. Highway cruising takes the temps up to 90-95C, depending on throttle, etc. Cruising at a constant 70, the temps were reading around 91C, and then when parked in stop and go traffic, the temps hit a high of 96C. After sitting in a garage for around 2 hours at lunchtime (ambient temps today were like 38C) the coolant was at 74C. Took all of 2 minutes to get back up to the 90s and thats how the temp cycle goes for my 325i.

So it seems that the normal operating temp is around 200F for my engine, with an ambient temp of 100F. Hope that helps.

Nice info clak192. Now if only BMW would find a way to fit a coolant temp gauge on the 3 series like on the new F01's.

[Reflex_nl]

@clark182: Thanks; that’s useful info. With your help I also managed to unlock the BC and show the coolant temp on the screen while driving.

I live in TX and the ambient temp during the test was about 26 C.

Cold start, the engine temp was already 60C. A few minutes of driving and it went up to 80 C. After 5 more minutes cruising on the highway the temperature stabilized at 98 C. When I parked the car or got into slow traffic the temperature increased rapidly to 105 C probably because of less airflow. As my garage is not well ventilated the car remained pretty warm during a decent break and when driving it quickly reached 97~99 C again. Our results are reasonably similar; it also could be that the 330i engine gets a bit hotter than the 325i.

---------
Anyone willing to post their results as well ??

[clark192]

Could be the case. The only question that remain is what is the relation between oil temps and coolant temps in our cars. Since coolant temps are all we have to go on, I just kind of approximate when its time to start pushing the car, and keep my fingers crossed that the oil is up to the task.

Also, I realized that I have the Gulf spec of the E90. Traditionally this meant that these cars, while Euro speced, also have beefier cooling systems. Not sure if that meant AC only, or AC and actual engine cooling. With what you reported it sounds like that may be the case, but this is just speculation here.

[clark192]

So I checked a friend more knowledgeable than I, and he thinks that, with a heat exchanger which we have, it takes roughly 3-5 minutes longer to heat up the oil than the coolant to operating temps. So in my experience it took me about 10 minutes to heat up the coolant to 90C, so it looks like 15 min of easy driving before you are ready to go.

[Reflex_nl]

Thanks for your thougths, I keep that in mind before pushing the car a bit more

[jhbodle]

Don't forget that the engines in the E90 run at different coolant temperatures depending on the operating condition. I believe that the range permitted is around 80 - 120 degrees C. Under very light loads the engine will run at 120C for maximum fuel economy. Under extreme loads and or high RPM, it will run at 80C for maximum performance. Most of the time it will run in 'normal' mode which is around 95C.

Incidentally, this is why there is no temperature gauge - it would fluctuate too much. You'll get a warning icon if the temp gets a bit hot, followed by a big red warning icon if the temperature gets dangerous for the engine.

Don't worry about the heat the engine gives off, when I first got my E90 325i home from the dealers brand new, the heat coming off the engine was incredible! They are designed to run hot.

[123Britt]

THis is one area that I am interested in learning from my NEW BT Scan Tool.
Things like: If I switch to Redline 5W-30 -- does the oil temp drop as claimed.

[hting]

Originally Posted by jhbodle

Don't forget that the engines in the E90 run at different coolant temperatures depending on the operating condition. I believe that the range permitted is around 80 - 120 degrees C. Under very light loads the engine will run at 120C for maximum fuel economy. Under extreme loads and or high RPM, it will run at 80C for maximum performance. Most of the time it will run in 'normal' mode which is around 95C.

Incidentally, this is why there is no temperature gauge - it would fluctuate too much. You'll get a warning icon if the temp gets a bit hot, followed by a big red warning icon if the temperature gets dangerous for the engine.

Don't worry about the heat the engine gives off, when I first got my E90 325i home from the dealers brand new, the heat coming off the engine was incredible! They are designed to run hot.

"Incidentally, this is why there is no temperature gauge - it would fluctuate too much. You'll get a warning icon if the temp gets a bit hot, followed by a big red warning icon if the temperature gets dangerous for the engine."

So the German engineers take out the temperature gauge because of the fluctuation and give us the fuel mileage gauge that doesn't have fluctuations ?
LOL....ok if it makes sense to you...

[jhbodle]

You resurrected a 7 year old thread just to say that? I would like a temperature gauge too but I'm pretty sure that BMW engineers know better than you or I do.

[Efthreeoh]

Originally Posted by hting

"Incidentally, this is why there is no temperature gauge - it would fluctuate too much. You'll get a warning icon if the temp gets a bit hot, followed by a big red warning icon if the temperature gets dangerous for the engine."

So the German engineers take out the temperature gauge because of the fluctuation and give us the fuel mileage gauge that doesn't have fluctuations ?
LOL....ok if it makes sense to you...

I have the N52 in my '06 325i and the N52 in my '08 Z4. The Z4 has a coolant temperature gauge. It doesn't fluctuate.

IMO the coolant temp gauge in the E90 was ditched for real estate reasons. The E90 gauge cluster is small so as to allow room for the Idrive screen.

[jhbodle]

Originally Posted by Efthreeoh

I have the N52 in my '06 325i and the N52 in my '08 Z4. The Z4 has a coolant temperature gauge. It doesn't fluctuate.

IMO the coolant temp gauge in the E90 was ditched for real estate reasons. The E90 gauge cluster is small so as to allow room for the Idrive screen.

The E36 and E46 had coolant gauges too, but they were artificial in many ways because the needle would stay right in the middle even though the temperature in those engines changed greatly during operation also. They made the 'normal' position cover a wider range of temperatures because the E30 (which more accurately reported coolant temperature) prompted lots of customers to go to the dealer reporting that the gauge was all over the place.

There's probably other reasons for it to be ditched like you said, but I know that is one of the reasons.

[Efthreeoh]

Originally Posted by jhbodle

The E36 and E46 had coolant gauges too, but they were artificial in many ways because the needle would stay right in the middle even though the temperature in those engines changed greatly during operation also. They made the 'normal' position cover a wider range of temperatures because the E30 (which more accurately reported coolant temperature) prompted lots of customers to go to the dealer reporting that the gauge was all over the place.

There's probably other reasons for it to be ditched like you said, but I know that is one of the reasons.

I had an E30 (1989 325i w/ an M20) for 18 years; i.e. since it was brand new. Coolant temp gauge never fluttered, ever.

[Three_thirty_I]

And as far as I know, the E92 (maybe some other variants) have a temperature gauge in place of the econometer, so the variation of temperatures is not the reason for there not being a temperature gauge in the E90, it's most likely just omitted due to lack of space. I just think that BMW should have figured out a way to fit a temperature gauge in the cluster with the space available!

[Phil325i]

Originally Posted by Three_thirty_I

And as far as I know, the E92 (maybe some other variants) have a temperature gauge in place of the econometer, so the variation of temperatures is not the reason for there not being a temperature gauge in the E90

I think you'll find the gauge in the E92 measures oil temp, not water. Oil temp does not fluctuate like the water temp. My understanding (as has already been said) is that water temp is not displayed because the water pump speed (and thereby engine water temp) varies according to driving conditions. So the gauge would be varying wildly and causing owners unnecessary panic.

[Efthreeoh]

Originally Posted by Phil325i

I think you'll find the gauge in the E92 measures oil temp, not water. Oil temp does not fluctuate like the water temp. My understanding (as has already been said) is that water temp is not displayed because the water pump speed (and thereby engine water temp) varies according to driving conditions. So the gauge would be varying wildly and causing owners unnecessary panic.

Then why does the coolant temp gauge in my N52-powered Z4 not fluctuate? Besides engine cooling systems keep the engine at the peak temperature for emissions and fuel consumption.

[kkasson]

Originally Posted by Efthreeoh

Then why does the coolant temp gauge in my N52-powered Z4 not fluctuate? Besides engine cooling systems keep the engine at the peak temperature for emissions and fuel consumption.

Has the Z4 ever overheated on you? I'm curious what the gauge did if so...I'm assuming that the gauge is buffered like it was on the E46. Did you have much time to react?

The E46 gauge wasn't super helpful because by the time it started to move the engine was basically overheating already. The N52 runs hotter than the M54 under normal conditions, so I think that having a coolant gauge would be even less useful. That's my best guess as to why there isn't one on the E90...it just wouldn't really be any more helpful than the warning light.

[Phil325i]

Originally Posted by Efthreeoh

Then why does the coolant temp gauge in my N52-powered Z4 not fluctuate?

Because the N52 has a mechanical water pump, not electric, maybe..?

[Efthreeoh]

Originally Posted by Phil325i

Because the N52 has a mechanical water pump, not electric, maybe..?

Okay now your are just guessing and making shit up....

The thermostat regulates the temperature of the engine cooling system. The electric coolant pump can assist in the control of cooling the engine in conjunction with the thermostat by varying the flow of the coolant. Like I said before for emissions and fuel consumption purposes the engineers design the engine to remain at a constant operating temperature.

I suggest you drop this topic and move on to something else.