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-   -   Watch my car overheat during AutoX, in HD -- What NOT to do! (http://forum.e46fanatics.com/showthread.php?t=864173)

LivesNearCostco 08-16-2011 06:14 PM

Watch my car overheat during AutoX, in HD -- What NOT to do!
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I mentioned in another thread my car overheated during an AutoX, 3 days after doing my cooling system refresh. But now you can watch it in Hi Definition video on YouTube. (Plus you can criticize my driving technique.) You'll see that everything is fine in the first run (that was actually my 6th run of the day) but it overheats halfway through the next run.

0:48 Start first run (6th of day)
3:45 Start 2nd run (7th of day), temp gauge looks normal
4:30 Temp needle rising towards red
4:44 Red idiot light goes on
4:45 Idiot fails to notice (watching the cones) :facepalm:
5:27 Red light goes off (why?)
7:38 Silly driver finally notices overheat and shuts down engine.

When I open the hood, steam and coolant were coming out of the ET cap. Ended up getting towed home, later found new aftermarket thermostat was stuck shut. Put old BMW thermostat back and now it's gone through 500 miles of driving and 2 more AutoX events and doesn't overheat. Knock on wood! I am SO ASHAMED :banghead: that I didn't see the red light and failed all the fanatics who have warned us not to drive with the temp gauge is in the red. My car ran in the "red zone" a full 3 minutes before I noticed and turned it off. I'm only posting the video now that it appears my head gasket survived intact.

So besides the horror of watching me ignore an overheat, a question! Why did the red light go off? It's not burned out because it still lights up whenever the key is turned to "on." Maybe the thermostat temporarily opened up a bit at the end of my run? Is there a coolant temp high enough to peg the needle in the red but low enough not to turn on the red light?


And here's my car back at Qualcomm Stadium last Saturday--not overheating. Got body roll?

Hornung418 08-16-2011 06:17 PM

Sounds like you are the perfect candidate for the 'Coolant Snitch!' Glad you survived through this, LNC.

southpaw 08-16-2011 06:18 PM



I'm bummed I couldn't make it to the one this past saturday.

dmax 08-16-2011 06:24 PM

I didn't see the video, but I suspect there is a temp where the light goes on, and you were at that temp...and then dropped below it enough that it went off...just like you thought.

Glad you're good, but keep a close eye on coolant level anyway.

genuity 08-16-2011 07:27 PM


Originally Posted by LivesNearCostco (Post 13489453)
later found new aftermarket thermostat was stuck shut.

It was that piece of crap MTC one, right?

ZHPRegistry 08-16-2011 08:29 PM

As another member mentioned, you are a perfect candidate for this product. Don't kick yourself in the head for not noticing the temp climb up. 1st off, the temp gauge is heavily buffered. You may in fact be in a situation when the coolant is excessively hot but the gauge hasn't begun its climb. This device is effective because it has no buffering, it reads off the sensor line with no digitized post processing. I (as well as few others) have been running this device since yearly this year with absolutely no adverse effects. Feel free to shoot me questions you might have.


Solidjake 08-16-2011 08:36 PM

That sucks man, I know exactly what you were feeling when you saw that needle up there.

LivesNearCostco 08-17-2011 01:05 PM

Thanks for the support, everyone. Yes I could benefit from a CoolantSnitch. Yes it was the aluminum bodied MTC thermostat; while waiting for the tow truck and trying to bleed the system, the heater circuit on the MTC thermostat also blew with a "pop" and small puff of smoke.

I felt guilty enough about it that I just changed the oil ahead of schedule, using a BMW approved Total Quartz oil, whereas before I was running Penzoil Ultra synthetic., which is supposed to be good stuff, but is not BMW LL approved. Not that the type of oil has anything to do with the cooling system, but it took away a little of my guilt.

Rubenk 08-17-2011 01:28 PM

I know on some thermostats, they have a "fail-safe" built in. Where when it reaches a certain temp, a peice within the thermostat melts and allows it to fully open. Once this occurs they will no longer close and must be replaced.

Does anybody know if our BMW thermostats are like that? I've replaced mine, but never looked at it that closely.

teamdfl 08-17-2011 01:47 PM

It's hard to believe that anyone could build a worse thermostat than Behr and Wahler but MTC seems to pull it off.

TiAgXi 08-17-2011 02:04 PM

You clearly hassled the Hoff when you weren't supposed to.

LivesNearCostco 08-18-2011 12:08 PM

+1, I will never hassle the Hoff again!

Usually when I hear about a BMW thermostat failing, it fails open, which reduces engine efficiency but does not risk overheating. Maybe MTC had a different philosophy...

LivesNearCostco 08-21-2011 01:25 AM

Made it through another AutoX today without overheating, making 3 AutoX events in 8 days on the good old thermostat, which apparently I shouldn't have replaced so soon. Still driving around with a new Wahler thermostat (exchanged for defective thermostat) in the trunk, along with a gallon of distilled water and my tools, in case I need to change it again. But since I'm fully prepared for thermostat failure, if something goes wrong no doubt it will be anything but the thermostat...

Today's AutoX was in Marina, CA on Motorsports Reunion weekend. So close to Laguna Seca, the classic racecars, and BMW Festorics, and didn't see any of it. Instead spent the whole day writing peoples' run times on sticky notes, taking a nap in my E46, and driving circles and slaloms around a windy aircraft parking lot 12 times. Last night I adjusted my rear camber in a hotel parking lot. At the last alignment it was -1.5 degrees on each side. No idea what it is now, except it's more negative than -1.5, hopefully -1.8 degrees. Did it help? Not sure, but no spins for me today, whereas I managed 3 spins in the last two AutoX events.

The silly things I do when my family is out of town...

new//M3fan 08-21-2011 02:04 AM

This is one of the reasons I'm considering selling my car and picking up an AP2 Honda S2000.

MTC thermostat or not; It is a possibility on a e46.

//TRD power 08-21-2011 06:27 AM

Mine was stuck open and I didn't know about it until winter time. Must have been driving like that for a year because once I changed that, the new pressure burst my expansion tank.

OneOfaKindTrini 08-21-2011 07:56 AM

.. Wow and it kept going.

LivesNearCostco 08-22-2011 03:37 PM

The car kept going? The thread? The thermostat? The dumb driver?

I was worried about a damaged head or head gasket and thought about doing a compression test myself or getting a leak-down test. My indie suggested it takes more than 3 minutes in the red zone to blow the HG. If my red light was accurate, I was dangerously overheated for only 43 seconds.

Mango 08-22-2011 03:46 PM

Awesome that you didnt fry your headgasket. What's not awesome is peoples MISGUIDED ASSUMPTIONS THAT BECAUSE A THERMOSTAT IS METAL (VS PLASTIC) THAT IT'S OMGGG BETTER than BMW's solution (OE parts)

There's NOTHING wrong with an OE/OEM thermostat--in fact it's the best g-damned option there is. Same goes for the water pump. So what they dont last 200k miles--you shouldn't be running your car that long without a cooling refresh anyway.

Quit it with the ALUMINUM THIS ALUMINUM THAT. Just buy the right OE or OEM parts and be done with it.

Mango 08-22-2011 03:49 PM


Originally Posted by teamdfl (Post 13492580)
It's hard to believe that anyone could build a worse thermostat than Behr and Wahler but MTC seems to pull it off.

How is it bad? Because it isn't machined out of solid block of titanium and/or isn't autocrosser fanboy bf.c stancewerkz approved? Just curious here... :shhh:

OE is the SHIZ

richyboycaldo 10-01-2012 03:15 PM

Been, there, I made a fool of myselft at my last autrocross, everybody hated me for leaking coolant at the track

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