coolant reservoir cap

iturbo_bmw · 11-16-2018, 09:48 PM

I was stopped a red light today when I heard a thud and all of sudden smoke started coming out of my engine. Took a look at the engine and the coolant reservoir tank a vertical crack in it a couple inches long. I was planning on just replacing it but I'm wondering why it exploded in the first place. what else could be going on here? head gasket? faulty cap?

How can i figure out the root case?

water pump/thermostat was replaced only like almost 2 years/15k miles ago so i don't think it could be that?

i did top off the coolant/water the other day. maybe i filled it up too high??

any codes i should look for or tests to run to help identify real issue here??

hassmaschine · 11-16-2018, 09:55 PM

Because you have a 335i and everything on it explodes suddenly?

iturbo_bmw · 11-16-2018, 09:58 PM

Quote:

Originally Posted by hassmaschine

Because you have a 335i and everything on it explodes suddenly?

lol forreal

unrulyteach · 11-17-2018, 12:01 AM

Quote:

Originally Posted by iturbo_bmw

Quote:

Originally Posted by hassmaschine

Because you have a 335i and everything on it explodes suddenly?

lol forreal

Haven't seen that before. Ik they tend to crack on the mounting points

N54Society · 11-17-2018, 03:16 AM

Sounds like you trapped some air bubbles, possibly. I'm not sure though because if you had water in the system, I would assume the bubbles were purged. You adding more to a purged system should trap more air but, maybe?

mecheng77 · 11-17-2018, 07:22 AM

It could have been an act of terrorism 😝

Boland01 · 11-17-2018, 07:57 AM

Age, heating and cooling cycles. Had the same thing happen to our 2007 335i. Good news is new ones are cheap. You might want to replace your crossover pipe too when you do it. Those get really brittle and crack if you look at them wrong.

Efthreeoh · 11-17-2018, 08:20 AM

The system should vent pressure way before that happens. Get a new cap too.

catcher22 · 11-17-2018, 09:15 AM

yep happened to me back in 16

Welcome to NBA Jam · 11-17-2018, 09:16 AM

I want to buy a new coolant cap now

iturbo_bmw · 11-17-2018, 02:34 PM

thanks for the help guys! I will order a new cap and reservoir tank

tcphoto · 11-17-2018, 03:11 PM

You probably overfilled the tank which caused an older tank split. It sounds like the new tank and cap should be all you need. Remember to pickup BMW coolant and distilled water and bleed correctly.

jg28xi · 06-11-2019, 12:20 AM

This happened to me.. I was driving my e92 328xi 2008. I had just got a new radiator installed, after getting it back from the dealer not even 5 miles and less than an hour after I got the car. I was driving and got the yellow indicator that my engine was to hot and then the red indicator that I was overheating. My car had stopped but i was stuck in the intersection so I turned on my car to pull it out of the intersection really quick but I heard a big pop on the right side of my hood. I immediately towed it back. the dealer called back today and let me know that it was the expansion tank that was blown... and that it happens due to the age of my car? Should i be worried if i a blew a headgasket?

unrulyteach · 06-11-2019, 11:05 AM

Quote:

Originally Posted by jg28xi

This happened to me.. I was driving my e92 328xi 2008. I had just got a new radiator installed, after getting it back from the dealer not even 5 miles and less than an hour after I got the car. I was driving and got the yellow indicator that my engine was to hot and then the red indicator that I was overheating. My car had stopped but i was stuck in the intersection so I turned on my car to pull it out of the intersection really quick but I heard a big pop on the right side of my hood. I immediately towed it back. the dealer called back today and let me know that it was the expansion tank that was blown... and that it happens due to the age of my car? Should i be worried if i a blew a headgasket?

Nope

Maestro · 06-11-2019, 11:10 AM

looks like the plastic became brittle over time which does not surprise me, I have a number of the plastic part on the coolant system crack and break. i too have 335I and it is 12 yrs old. I am not impressed with the type of plastic BMW is using under the hood. The plastic water level indicator in my expansion tank broke off a couple years ago, I open the cap to add water one change and it was just sitting in broken off, never touch it.

iturbo_bmw · 06-11-2019, 11:31 AM

Quote:

Originally Posted by jg28xi

This happened to me.. I was driving my e92 328xi 2008. I had just got a new radiator installed, after getting it back from the dealer not even 5 miles and less than an hour after I got the car. I was driving and got the yellow indicator that my engine was to hot and then the red indicator that I was overheating. My car had stopped but i was stuck in the intersection so I turned on my car to pull it out of the intersection really quick but I heard a big pop on the right side of my hood. I immediately towed it back. the dealer called back today and let me know that it was the expansion tank that was blown... and that it happens due to the age of my car? Should i be worried if i a blew a headgasket?

No, but if your car was overheating before the pop then your water pump probably died

BeaterM3 · 06-14-2019, 09:24 AM

Quote:

Originally Posted by hassmaschine

Because you have a 335i and everything on it explodes suddenly?

Haha not just the 335i. The expansion tank on my old E36 just decided to burst as well lol.

11-16-2018, 09:48 PM	#1
iturbo_bmw Major 84 Rep 1,099 Posts Drives: 335i, 530i Join Date: Oct 2012 Location: San Jose iTrader: (0)	coolant reservoir cap I was stopped a red light today when I heard a thud and all of sudden smoke started coming out of my engine. Took a look at the engine and the coolant reservoir tank a vertical crack in it a couple inches long. I was planning on just replacing it but I'm wondering why it exploded in the first place. what else could be going on here? head gasket? faulty cap? How can i figure out the root case? water pump/thermostat was replaced only like almost 2 years/15k miles ago so i don't think it could be that? i did top off the coolant/water the other day. maybe i filled it up too high?? any codes i should look for or tests to run to help identify real issue here?? Attached Images Last edited by iturbo_bmw; 10-30-2019 at 02:13 PM..
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11-16-2018, 09:55 PM	#2
hassmaschine Major General 3966 Rep 7,215 Posts Drives: "NBO" 330i Join Date: Jun 2014 Location: earth iTrader: (0)	Because you have a 335i and everything on it explodes suddenly?
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11-17-2018, 03:16 AM	#5
N54Society Major Private First Class 449 Rep 1,327 Posts Drives: 2010 E90 335i M Sport Join Date: Mar 2014 Location: US, NA, Earth, Milky Way Galaxy iTrader: (2)	Sounds like you trapped some air bubbles, possibly. I'm not sure though because if you had water in the system, I would assume the bubbles were purged. You adding more to a purged system should trap more air but, maybe? __________________ 2008 E92 335i 6MT: FBO + MMP Silicone Inlets \| Stage 1 LPFP \| 335is clutch + MFactory SMFW \| Custom BuraQ + MHD tune \| 3.5Bar N20 sensor [SOLD] 2010 E90 335i M-Sport AT: 5" Stepped FMIC, Stage 2 LPFP - MHD V7 E60 Tune running 100% E85 - VRSF DPs
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11-17-2018, 07:22 AM	#6
mecheng77 Colonel 1006 Rep 2,243 Posts Drives: 2007 328i / 2014 M235i Join Date: Nov 2017 Location: Ontario Canada iTrader: (0) Garage List [0.00] [0.00]	It could have been an act of terrorism 😝
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11-17-2018, 07:57 AM	#7
Boland01 Lieutenant 149 Rep 460 Posts Drives: 2010 535ix, 2008, 2007 335i Join Date: Sep 2013 Location: Magnolia, TX iTrader: (0)	Age, heating and cooling cycles. Had the same thing happen to our 2007 335i. Good news is new ones are cheap. You might want to replace your crossover pipe too when you do it. Those get really brittle and crack if you look at them wrong.
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11-17-2018, 08:20 AM	#8
Efthreeoh General 17281 Rep 18,722 Posts Drives: The E90 + Z4 Coupe & Z3 R'ster Join Date: May 2012 Location: Virginia iTrader: (0)	The system should vent pressure way before that happens. Get a new cap too. __________________ A manual transmission can be set to "comfort", "sport", and "track" modes simply by the technique and speed at which you shift it; it doesn't need "modes", modes are for manumatics that try to behave like a real 3-pedal manual transmission. If you can money-shift it, it's a manual transmission. "Yeah, but NO ONE puts an automatic trans shift knob on a manual transmission."
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11-17-2018, 09:15 AM	#9
catcher22 Captain 294 Rep 922 Posts Drives: 2008 335xi Coupe Join Date: May 2008 Location: Virginia iTrader: (2)	yep happened to me back in 16
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11-17-2018, 09:16 AM	#10
Welcome to NBA Jam Is it the shoes!? 3884 Rep 5,112 Posts Drives: (Sold) 2011 E92 335i ZMP 6MT Join Date: Mar 2014 Location: USA iTrader: (1)	I want to buy a new coolant cap now
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11-17-2018, 02:34 PM	#11
iturbo_bmw Major 84 Rep 1,099 Posts Drives: 335i, 530i Join Date: Oct 2012 Location: San Jose iTrader: (0)	thanks for the help guys! I will order a new cap and reservoir tank
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11-17-2018, 03:11 PM	#12
tcphoto Brigadier General 3531 Rep 3,046 Posts Drives: E92 335i 6MT Coupe Join Date: Dec 2009 Location: Nashville, TN iTrader: (1)	You probably overfilled the tank which caused an older tank split. It sounds like the new tank and cap should be all you need. Remember to pickup BMW coolant and distilled water and bleed correctly. __________________
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06-11-2019, 12:20 AM	#13
jg28xi New Member 0 Rep 9 Posts Drives: 2008 328xi Join Date: Jun 2019 Location: Los Angeles iTrader: (0)	This happened to me.. I was driving my e92 328xi 2008. I had just got a new radiator installed, after getting it back from the dealer not even 5 miles and less than an hour after I got the car. I was driving and got the yellow indicator that my engine was to hot and then the red indicator that I was overheating. My car had stopped but i was stuck in the intersection so I turned on my car to pull it out of the intersection really quick but I heard a big pop on the right side of my hood. I immediately towed it back. the dealer called back today and let me know that it was the expansion tank that was blown... and that it happens due to the age of my car? Should i be worried if i a blew a headgasket?
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06-11-2019, 11:10 AM	#15
Maestro Major 1013 Rep 1,268 Posts Drives: 2007 335i Sedan, 2021 X3 Join Date: Nov 2006 Location: Philadelphia iTrader: (0)	looks like the plastic became brittle over time which does not surprise me, I have a number of the plastic part on the coolant system crack and break. i too have 335I and it is 12 yrs old. I am not impressed with the type of plastic BMW is using under the hood. The plastic water level indicator in my expansion tank broke off a couple years ago, I open the cap to add water one change and it was just sitting in broken off, never touch it.
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