[EricD735i]

My 328d seems to take forever to warm up. Drove around town (low speed, stop & go) earlier today with my Foxwell hooked up and after 25-30 min coolant temp finally got to 180. Last regen was 65 miles ago per the scan tool so it’s getting up to temp eventually. Car has 68k miles. Wondering if I should swap out the thermostat before the MN winter gets going. For comparison wife’s X3d heats up on the gauge in just a few miles.

[Enabled]

Good call on using a diagnostic tool to read coolant temperature, since the gauge is oil temp.

I would agree that you have a stuck open thermostat.

[Watsey]

Originally Posted by Enabled

Good call on using a diagnostic tool to read coolant temperature, since the gauge is oil temp.

I would agree that you have a stuck open thermostat.

This ^ Almost certainly a stuck open 'stat.

[EricD735i]

Gonna get the parts ordered. Didn’t realize the part is shared with the 35d cars. Those seem to have a lot of issues with broken thermostats.

[n00bkiller944]

Originally Posted by EricD735i

My 328d seems to take forever to warm up. Drove around town (low speed, stop & go) earlier today with my Foxwell hooked up and after 25-30 min coolant temp finally got to 180. Last regen was 65 miles ago per the scan tool so it’s getting up to temp eventually. Car has 68k miles. Wondering if I should swap out the thermostat before the MN winter gets going. For comparison wife’s X3d heats up on the gauge in just a few miles.

How did you know your car was taking an extended time to warm up prior to hooking the scan tool? One of the reasons I hate not having a coolant temp gauge is to monitor things like this.

[Watsey]

Originally Posted by n00bkiller944

How did you know your car was taking an extended time to warm up prior to hooking the scan tool? One of the reasons I hate not having a coolant temp gauge is to monitor things like this.

The oil temp does provide an indication of engine temperature. The oil temp is by far the best indicator of when the engine is in an acceptable/safe operating temperature range for driving the engine hard.

The coolant temp can be accessed by using the OBC hidden menu.

Here's a YT guide showing how to unlock it :

[Enabled]

I totally agree, oil temp is a much better indicator for overall engine temp.


Coolant temp is simply quicker to respond if there is an overheat condition, but you will definitely get warnings from the cluster and navigation system if the coolant temp goes too high.

[AlpineX]

Originally Posted by EricD735i

My 328d seems to take forever to warm up. Drove around town (low speed, stop & go) earlier today with my Foxwell hooked up and after 25-30 min coolant temp finally got to 180. Last regen was 65 miles ago per the scan tool so it’s getting up to temp eventually. Car has 68k miles. Wondering if I should swap out the thermostat before the MN winter gets going. For comparison wife’s X3d heats up on the gauge in just a few miles.

2 days in a row I'm at 20 min to get to 88c. This is speed up to 40mph, ambient temp 45F and 55F. Bit long for my liking.

[EricD735i]

Originally Posted by n00bkiller944

How did you know your car was taking an extended time to warm up prior to hooking the scan tool? One of the reasons I hate not having a coolant temp gauge is to monitor things like this.

Just the oil temp gauge taking forever to get up to temp compared to my wife’s car with same engine.

[EricD735i]

So I’ve got the car apart replacing the thermostat. Unfortunately the one I ordered didn’t come with the correct gasket so I’m waiting for my dealer to get one. Someone smarter than I am explain to me how this could fail open.







The little pin in the top of the thermostat fits into a corresponding hole in the housing. From what I can tell as the coolant heats up the pin extends and pushes that end away from the housing letting coolant flow. The big spring applies pressure in the opposite direction closing the flow. If the pin didn’t move I don’t see how it can fail open. What am I missing?

[mafatbhai]

Was there any check engine light or code in the ecu?

I am experiencing the same issue.
I have no check engine light. Dealer thinks its fine.

Oil temp gauge is remaining almost at 160F for good 30+ miles before it starts moving. Goes up to 210 F eventually.

Checked the coolant temp using hidden code on dash and it was hovering at 75 C for that time and climbed to 89C eventually after 30+ miles and 30 minutes of driving..

Outside temp was 28 F. Car mileage has dropped to 30 mpg from 38 mpg.

Any suggestions ?

[EricD735i]

No CEL, and took forever to warm up like yours. Everything seems back to proper operation now. Definitely feels like power has increased now that it’s getting up to proper temp so it either did a good regen or it was never getting past the cold engine mapping.

[expl0de]

My car - 328d, takes about 20 minutes to get to operating temperature, but once there it stays there. Do you think this could be bad stat? My father's car is 530d and it gets to operating temp for less than 10 minutes. Both cars have the engine insulation, only his is 6 cyl. vs 4 cyl.

[HighlandPete]

Originally Posted by expl0de

My car - 328d, takes about 20 minutes to get to operating temperature, but once there it stays there. Do you think this could be bad stat? My father's car is 530d and it gets to operating temp for less than 10 minutes. Both cars have the engine insulation, only his is 6 cyl. vs 4 cyl.

Are both engines reading oil temperature? What does the hidden menu show for the warm up phase, both for oil and coolant (ECT)?

From the topic discussion above, it is possible that the thermostat is opening at a lower than rated temperature, rather than being stuck open.

M47/57 engines had a common issue of 'stats opening at lower than rated temperatures, as they aged. Not been a common problem with the different thermostat in the N47/57 engines.

The fact you get there eventually, and temperature stays there, is the puzzling bit. Do you mean the ECT stays around the 88 - 90C design figure? Or are you referencing the oil temperature from the gauge?

[capt_slow]

I always noticed this car was slow to warm up, but always thought it was normal behavior. When I saw this thread, I thought I post up some measurements.

I went right to highway driving after going from a cold start, so engine RPMs were 1000-2000. It was idling for about 5 mins before going straight to 65ish MPH.

Time, Mileage, Oil temp (gauge cluster)
9:46, 24894, 120F (lowest gauge will go)
9:53, 24897, 121F (gauge begins moving)
9:58, 24902, 165F
10:03, 24908, 210F (normal operating temp)

So it took 17 minutes and 14 highway miles to bring the temps up to normal. Ambient temp was 66-68F according the gauge cluster.

[AlpineX]

How about ambient temp, brief description of the drive profile including any still warm up, temp measuring device, time elapsed and temp, specify oil temp or water temp.
Could be useful for people to compare.

[mafatbhai]

Originally Posted by EricD735i

No CEL, and took forever to warm up like yours. Everything seems back to proper operation now. Definitely feels like power has increased now that it’s getting up to proper temp so it either did a good regen or it was never getting past the cold engine mapping.

Did you check the old thermostat after replacing it ? Was it really failed open?

I am getting varying degree of coolant rise. Some days it rises up in like 10 min 10 miles (even on 19 F day) and some days its takes like good 25 minutes 25-30 miles on a 48 deg day..

I am contemplating replacing the thermostat.

Also the car seems to regulate the coolant temp at 190F after warming up. The coolant measurement is on hidden gauge cluster and on INPA.

[EricD735i]

I never checked it but all seems back to normal now.

[mafatbhai]

Originally Posted by EricD735i

I never checked it but all seems back to normal now.

How difficult was it to replace the thermostat. ? Is bleeding procedure easy? just fill and let it burp or have to use INPA to turn on the water pump etc ?

[mafatbhai]

Originally Posted by EricD735i

I never checked it but all seems back to normal now.

Originally Posted by HighlandPete

Are both engines reading oil temperature? What does the hidden menu show for the warm up phase, both for oil and coolant (ECT)?

From the topic discussion above, it is possible that the thermostat is opening at a lower than rated temperature, rather than being stuck open.

M47/57 engines had a common issue of 'stats opening at lower than rated temperatures, as they aged. Not been a common problem with the different thermostat in the N47/57 engines.

The fact you get there eventually, and temperature stays there, is the puzzling bit. Do you mean the ECT stays around the 88 - 90C design figure? Or are you referencing the oil temperature from the gauge?

When does the thermostat start opening?

The coolant temp on hidden gauge shows 89- 90 deg and stays there once its driven 30+ miles..

[EricD735i]

Originally Posted by mafatbhai

How difficult was it to replace the thermostat. ? Is bleeding procedure easy? just fill and let it burp or have to use INPA to turn on the water pump etc ?

Not too bad. It’s a little tricky lining it up because it’s at a funny angle. Buy the whole housing with the gasket. I bought just the thermostat online and it came with the wrong gasket. N47 does not have an electric water pump (you may want to replace the pump while you’re in there if you have some miles on it) but bleeding wasn’t an issue. Just fired it up and topped it off once warmed up (turn the heat on high). After a couple of drives and topping off it was fine.

[mafatbhai]

Originally Posted by EricD735i

Not too bad. It’s a little tricky lining it up because it’s at a funny angle. Buy the whole housing with the gasket. I bought just the thermostat online and it came with the wrong gasket. N47 does not have an electric water pump (you may want to replace the pump while you’re in there if you have some miles on it) but bleeding wasn’t an issue. Just fired it up and topped it off once warmed up (turn the heat on high). After a couple of drives and topping off it was fine.

Thanks Eric.

The folks at local BMW store are recommending just the thermostat and gasket change. I will be doing that in the upcoming days.