08 3.0Si Engine and Possible Cool Issues

Our03z4 · 02-12-2023, 04:58 PM

Car gets up to 103c while sitting idling in 50f weather. That's 217f, seems high, right? Replaced the entire coolant system around 10k miles ago so would doubt it's that.

No code for cooling issues but I do get both codes every now and then for DISA and exhaust manifold pressure sensor. It's a black cover engine so not the normal CCV system instead it's built in to the valve cover. Had an issue with that months ago and replaced just the valve.
Seems to be running slightly rough or bounces at low idle. So ordering parts for those issues. Also the vac lines look good. Slight leak on the valve cover under racing conditions.

Battery is only a few months old and gets trickled charged. Battery check good and good charging on Carly.

Ideas and if the coolant temp is an issue? Thanks!

Our03z4 · 02-12-2023, 05:01 PM

I should also say that the intake and ambient temps are way off. Says it should only be a 10 max difference but instead it's 40. So the intake is 122f degrees. What causes this?

rjahl · 02-14-2023, 05:38 AM

Try researching the engine management system for the N52. The DME controls the coolant temperature and has several modes. Eco mode has a 105 degrees C set point. No, you can’t change it without reprogramming your DME. Not worth the effort anyway. You won’t make more power and you won’t make your engine last longer.

Intake air can get crazy high when sitting in traffic. Do you have a stock cold air intake or are you pulling air from within the engine bay?

Steeler · 02-14-2023, 07:15 AM

Quote:

Originally Posted by Our03z4

I should also say that the intake and ambient temps are way off. Says it should only be a 10 max difference but instead it's 40. So the intake is 122f degrees. What causes this?

The ambient air temp sensor is under the left side front bumper, sounds like it's gone out. I had one fail on me.

Can't help with your engine issues and far as I know the AAT sensor does not affect the ECU.

https://www.e46fanatics.com/threads/...#post-16226851

Coi · 02-27-2023, 09:44 PM

That coolant temp isn't insanely high for idling. Maybe a little more than expected. Does it go down right away when you start driving?

I would assume that the the 3.0si has an electric fan rather than a fan clutch since it's an N52. Might still be worth checking to see if the fan is running properly and pushing enough air. If you turn the A/C on the fan should ramp up so that's another test you can try.

02-12-2023, 04:58 PM	#1
Our03z4 Captain 1690 Rep 685 Posts Drives: 2008 BMW Z4 3.0si Coupe, Join Date: Nov 2016 Location: USA iTrader: (0)	08 3.0Si Engine and Possible Cool Issues Car gets up to 103c while sitting idling in 50f weather. That's 217f, seems high, right? Replaced the entire coolant system around 10k miles ago so would doubt it's that. No code for cooling issues but I do get both codes every now and then for DISA and exhaust manifold pressure sensor. It's a black cover engine so not the normal CCV system instead it's built in to the valve cover. Had an issue with that months ago and replaced just the valve. Seems to be running slightly rough or bounces at low idle. So ordering parts for those issues. Also the vac lines look good. Slight leak on the valve cover under racing conditions. Battery is only a few months old and gets trickled charged. Battery check good and good charging on Carly. Ideas and if the coolant temp is an issue? Thanks! Attached Images
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02-12-2023, 05:01 PM	#2
Our03z4 Captain 1690 Rep 685 Posts Drives: 2008 BMW Z4 3.0si Coupe, Join Date: Nov 2016 Location: USA iTrader: (0)	I should also say that the intake and ambient temps are way off. Says it should only be a 10 max difference but instead it's 40. So the intake is 122f degrees. What causes this?
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02-14-2023, 05:38 AM	#3
rjahl Colonel 996 Rep 2,287 Posts Drives: Z4 35is Join Date: Jun 2011 Location: Tampa iTrader: (0) Garage List 2012 Z4 35is [0.00]	Try researching the engine management system for the N52. The DME controls the coolant temperature and has several modes. Eco mode has a 105 degrees C set point. No, you can’t change it without reprogramming your DME. Not worth the effort anyway. You won’t make more power and you won’t make your engine last longer. Intake air can get crazy high when sitting in traffic. Do you have a stock cold air intake or are you pulling air from within the engine bay?
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02-27-2023, 09:44 PM	#5
Coi First Lieutenant 289 Rep 323 Posts Drives: 21 X3 M40i, 07 Z4MR Join Date: Mar 2021 Location: Cal iTrader: (0)	That coolant temp isn't insanely high for idling. Maybe a little more than expected. Does it go down right away when you start driving? I would assume that the the 3.0si has an electric fan rather than a fan clutch since it's an N52. Might still be worth checking to see if the fan is running properly and pushing enough air. If you turn the A/C on the fan should ramp up so that's another test you can try.
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