Squeal then white smoke?!

BaconDouble · 04-28-2024, 07:44 PM

Today I had the first “incident” my engine, hope it’s nothing serious.

Car is a 2019 340 GT with 48,000 miles.

I did some maintenance including an oil change with 0w-40 Mobil1 (LL-01) approx 6.5 quarts until I can get an accurate reading.

I also replaced both coolant/expansion tank caps (little and big one) and verified both tanks were filled between the Min/Max marks.

Then I used the car for about 2 hours doing errands and driving about 25 miles.

At home, I sat in my driveway with the A/C on and let my son nap for about 30 minutes (he falls asleep easily in the car.). I’ve done this countless times, idling in the driveway with either the A/C or heater on to let my son continue his nap.

After about 30 minutes, I felt the RPMs change and then heard a medium loud screeching/squealing from the engine and then noticed white smoke from the exhaust. I shut the car down right away. I checked the engine bay, nothing obvious although I expected to see a glowing red-hot turbo or something else.

I waited about 10 minutes, used my scan tool to check for any codes and there were none. No lights on the dash, and no other warning lights.
The car certainly has oil, coolant as I just checked. Temp needle was right in the middle, as it always is.

I started the car and it seemed fine again. The white smoke cleared up and I gave it some gentle revs. No lights on the dashboard. Normal engine temp per the gauge.
I tried stopping and restarting again just to see if it would happen again - but it’s like nothing happened, everything seems fine again.

What do you think happened and did I do any damage?

B58togo · 04-28-2024, 10:43 PM

Sounds like textbook failed PCV diaphragm, but it's odd that it went away.

G.Newt · 04-28-2024, 11:53 PM

PCV diaphragm. That part is specifically covered under an extended warranty rom BMW. The permanent fix is to get a Ross Racing PCV delete kit.

BaconDouble · 04-29-2024, 11:19 AM

Thanks for the replies all. I'll take a look at replacing my PCV.

Searched a few other threads and it seems excessive idling and higher boost can certainly cause this issue quicker.

04-28-2024, 07:44 PM	#1
BaconDouble Private First Class 59 Rep 132 Posts Drives: 19 F34 340i xDrive GranTurismo Join Date: Aug 2018 Location: Philadelphia iTrader: (0)	Squeal then white smoke?! Today I had the first “incident” my engine, hope it’s nothing serious. Car is a 2019 340 GT with 48,000 miles. I did some maintenance including an oil change with 0w-40 Mobil1 (LL-01) approx 6.5 quarts until I can get an accurate reading. I also replaced both coolant/expansion tank caps (little and big one) and verified both tanks were filled between the Min/Max marks. Then I used the car for about 2 hours doing errands and driving about 25 miles. At home, I sat in my driveway with the A/C on and let my son nap for about 30 minutes (he falls asleep easily in the car.). I’ve done this countless times, idling in the driveway with either the A/C or heater on to let my son continue his nap. After about 30 minutes, I felt the RPMs change and then heard a medium loud screeching/squealing from the engine and then noticed white smoke from the exhaust. I shut the car down right away. I checked the engine bay, nothing obvious although I expected to see a glowing red-hot turbo or something else. I waited about 10 minutes, used my scan tool to check for any codes and there were none. No lights on the dash, and no other warning lights. The car certainly has oil, coolant as I just checked. Temp needle was right in the middle, as it always is. I started the car and it seemed fine again. The white smoke cleared up and I gave it some gentle revs. No lights on the dashboard. Normal engine temp per the gauge. I tried stopping and restarting again just to see if it would happen again - but it’s like nothing happened, everything seems fine again. What do you think happened and did I do any damage? Last edited by BaconDouble; 04-28-2024 at 08:10 PM..
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04-28-2024, 10:43 PM	#2
B58togo Major 809 Rep 1,372 Posts Drives: M240i Join Date: Feb 2017 Location: NY iTrader: (0)	Sounds like textbook failed PCV diaphragm, but it's odd that it went away. __________________ 2017 M240i/ ZF8 Pure Drivetrain Solutions Stage 1 & torque converter/xHP/ DAW Ultra Flow/ DS2/ Nostrum injectors/ E40 Doug Newton tuned/ ER DP/ Remus axle back/ BMS intake/ FTP CP/ M Perf LSD
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04-28-2024, 11:53 PM	#3
G.Newt Major 810 Rep 1,456 Posts Drives: CT4-V Blackwing 6MT Join Date: Feb 2017 Location: CO -> TX iTrader: (0)	PCV diaphragm. That part is specifically covered under an extended warranty rom BMW. The permanent fix is to get a Ross Racing PCV delete kit. __________________ 2022 CT4-V Blackwing 6-speed SOLD: 2016 340i xDrive 6-speed DAW v2.5 turbo E40 \| Dorch S2 \| VRSF DP \| MST intake \| AWE catback \| 335is clutch \| CSF heat exchanger \| RK Autowerks intake manifold \| Orange M Perf Brake Kit \| KW Street Comfort coilovers \| GTS taillights V2
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04-29-2024, 11:19 AM	#4
BaconDouble Private First Class 59 Rep 132 Posts Drives: 19 F34 340i xDrive GranTurismo Join Date: Aug 2018 Location: Philadelphia iTrader: (0)	Thanks for the replies all. I'll take a look at replacing my PCV. Searched a few other threads and it seems excessive idling and higher boost can certainly cause this issue quicker.
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