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Loud POP! Then Smoke... Help?

65K views 33 replies 15 participants last post by  RRRM8E  
#1 ·
I'm sitting in a parking lot with my AC on and all the sudden I heard a loud POP and all this white smoke or steam was coming from under my hood. I turned my car off and walked around my car. I noticed a lot of water under my car. I restarted my car and it started up fine, but the radiator symbol came on.

What happened and how much is this going to cost me?

Thanks!
 
#3 ·
I was just sitting in the parking lot and something popped. I doubt anything hit it as I was just sitting there waiting. Its got to be something else.

If it's any help, my AC has been weak for a year now and it makes a hissing noise. It started to make the noise again before the POP sound came.
 
#4 ·
You should not have started up the car again and you shouldn't be driving it.

Search cooling system overhaul...and if you had the temp gauge go into the red...and maybe a red light appear next to it which you were also wondering about...then search head/head gasket...and I hope this didn't happen or that you didn't drive more than a few hundred feet. That's the story of how in my ignorance I cracked my cylinder head in my e36, got it fixed for $2500 and then had the car totaled 6 months later. Hopefully your mileage will vary.

It's a very expensive machine you have...worth it to read the owner's manual whenever a light comes on and you don't know what it means. It always means something...some you can ignore for a little bit, but if you don't know which ones that's the case for, you can't ignore any of them.

No manual...get one and keep it in car, or get manual online and download to your pda or something.

Hope this doesn't turn expensive for you...really do! Didn't mean to be 'sharp,' but I'm one of those reformed, hypocritical know-it-alls...all prompted from the incident I had...so try to help others avoid that here all I can. Hope I wasn't too late!

Doug
 
#7 ·
Probably something in you AC gave way. Turn the car on and adjust your OBC to show the engine temp and monitor it while it runs. Then turn your AC on and see if it cools the air coming in. Because a loud pop and white smoke is r134a. If you did not see any water under the car after the pop it was an AC line or some AC component going.
 
#9 ·
He had radiator light come on, NPV, and had water on the ground...and he should not turn car on again. I know you're pretty newish here, but be careful, coz I've seen fanatics take the only advice they've received at times, even if it's wrong...just coz it's all they had. Fortunately, I keep an eye out when I'm around...and know many others have OPs' backs too!

Doug
 
#8 ·
Whew!

You blew up something, but the thing that blew up probably isn't the only issue, though it might be...but at least now we don't have to worry about your car.

ET is most likely, but who knows...anything that popped off would make a pop...the system is under pressure.

So, if you're diy capable (sounds like you'd have a lot of studying to do)...have some basic tools, etc, and can read and follow many conflicting directions (important key!)...get car towed to your home. If not, towed to shop you trust.

If diy...then $300 buys you all the parts you'd most likely need and gives you a new cooling system (how many miles on car?).

If not diy, you'll spend $400 and maybe get a new thermostat...or for $400 maybe just new ET, or for $500...therm and maybe a new hose.

This is many fanatics first diy...it is doable...and since I don't have to see you crying...I recommend it, even if you don't think you're handy, I can already tell your savvy enough...as in you write well, so probably think well...plus or minus.

Depending on your city, you might try crying now and getting someone to help here (you're not in NJ are you? LOL).

If you need a shop, search regional forum.

...and if not, then start reading and learning and order a cooling overhaul kit, as I'm sure you'll need at least two of the parts of it.

Auto or manny? If auto, you need a special tool or to do more reading.

That's it for me for now, OP...HTH, and start the studying...and please, not worth the risk to drive, so hope you can either leave car where it is, or get it towed.

BTW, very common...the cooling system failing...so you're not a bad person...not the wrath of god or anything...I'm reasonably sure!

Doug
 
#11 ·
My car has a dash over 100K. Maybe around 103,000? It's a five speed transmission and the only issue I have ever had with the car seems to be the AC. This issue didn't seem like the AC, but that was the first thing that came to mind when I heard the popping noise.

Coincidentally my car is right next to a Sears Service Center at a Mall. Should I turn my car on to look for a few specifics?
 
#12 ·
In case you mean me...and I suspect you do since I wrote tons above...you obviously haven't read any of my posts before, Mach.

If I know more than two words that might apply, I type them...and very quickly. The caffeine and heavy drug use rarely affect my typing speeeeeeeeeeed or qualiteeeee of my thinking. But, if I've mislead in any way, please correct....like to learn while I try to help.

Doug
 
#14 ·
An A/C leak would spill gas into the atmosphere and you probably wouldn't even notice. Hate to say it, but you've got a new problem on your hands.

The cooling system is under pressure, so that "pop' you heard followed by the sounds of rushing water was a part of that system giving way. Expansion tanks are notorious, but a bleeder screw or hose is another possibility. The plastic fittings on the radiator can also break. Just follow that leak to the source. Grab some distilled water if you need to fill the system with more fluid. You'll most likely need to get under the car and see where it's coming from.
 
#15 · (Edited)
My money's on expansion tank. Mine did exactly what yours did in a Starbuck's drive-thru. I was sitting there waiting for my drink when I heard a big pop, a burst of steam from under the hood, and a sudden flow of coolant from under the car. The tank had a nice split right down the side. With 100k miles it was due to go.

You probably also have another problem mine did: Malfunctioning electric fan. When you're not moving and the fan doesn't run like it is supposed to coolant temps go up (not that you'd know with our buffered gauges) and increase pressure on the cooling system. At the same time the A/C condenser heats up increasing A/C system pressure. (and putting extra load on the cooling system) This decreases efficiency and in my car it also made it start a hissing noise from the A/C expansion valve in the dash. Once I put 1 and 1 together, I knew when my coolant temps were starting to go up this way. Once the A/C started to hiss and didn't blow air as cold as it used to I knew to shut off the A/C to let everything cool down and/or find a way around traffic so the airflow of 45+mph speeds could flow through the radiator. The coolant temperature gauge will only start to go past the 12 o'clock position when you're riding the ragged edge of overheating already.

My prediction for what you need:
- A tow to get your car home
- New expansion tank
- A gallon of BMW coolant
- A gallon or two of distilled water
- New electric fan

I'd also recommend while you're in there:
- New upper and lower radiator hoses
- New coolant temperature sensor for lower hose

Inspect ET...white canister on left side of radiator (left if sitting in car, not looking at it) with black top. If cooled down, open up et cap and see whether you see a bobber 'stick' sticking up...doubt you will.
My expansion tank (old one and replacement) is all black...
 
#16 ·
I just want to thank everyone for helping me out yesterday. I removed my air filter only to find that my expansion tank had a huge crack in it. I went to the local BMW service center and purchased a new tank for $100. It took a few hours to get it all taken apart and put back together since I wasn't very familiar with it, but I go it done. Here are a few pictures to show you what I saw. Thanks again for everyone's help.
 

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#28 ·
Do it right the first time

At 103,000 and seeing your photos you will have other issues with your cooling system for certain. The cooling system parts give out like clock work at at certain mileage points, this is my experience talking! You will be looking at a huge cost including engine replacement and or head gasket R&R if that BMW engine overheats! Do yourself a favor, if you managed to replace the expanion tank in a mall parking lot, you are quite capiable of addressing ALL issues of the cooling system and the dependability of your BMW. At 100,000 miles DO REPLACE EVERYTHING in this cooling system, there are kits sold for this very reason. the kits have all the parts known to go out. Select a good one and Practice known preventive care when doing your own DIY's. Here is a link for a kit, it is very cost effective when concidering what a failed cooling can do.
http://www.bmw330ci.net/maintenance/completecoolant.php

And while your at it take the time to do your belts and pulleys, these people also have cooling system kits; http://www.ecstuning.com/BMW-E46-330i-M54_3.0L/Engine/Drive_Belts/
do enter the last four of your vin number so your assured of correct parts the first time.
Lastly; use this site for any and all diagrams for parts before you order;
http://www.realoem.com/bmw/partgrp.do?model=EV53&mospid=47725&hg=11&fg=35

(I as well depend on the forum, utube and all the information presented. I check EBAY for deals with part numbers i know are correct. I really knew nothing about my BMW until i discovered e46fanatics, you guys are very smart, THANK YOU GUYS VERY MUCH, so i am returning the favor to someone else through this reply.
I hope this is of use to you.
fixthatbmw,Orange County,Ca
 
#32 ·
I'm sitting in a parking lot with my AC on and all the sudden I heard a loud POP and all this white smoke or steam was coming from under my hood. I turned my car off and walked around my car. I noticed a lot of water under my car. I restarted my car and it started up fine, but the radiator symbol came on. What happened and how much is this going to cost me? Thanks!
Happened to my daughter as she was driving. Smoke under hood, heat not work suddenly, loud pop noise. My husband works with cars..said looks like needed anti-freezw coolant. Something overheated. Why heat not work. Shuts down as overheating. Msybe not same issue aa you but maybe help someone
I'm sitting in a parking lot with my AC on and all the sudden I heard a loud POP and all this white smoke or steam was coming from under my hood. I turned my car off and walked around my car. I noticed a lot of water under my car. I restarted my car and it started up fine, but the radiator symbol came on. What happened and how much is this going to cost me? Thanks!
Needs antifreeze collant. Heat or A/C will shut off becauss car iverheats from coolant coming out