Surge tank explosion
Instructor
Joined: Mar 2005
Posts: 174
Likes: 3
From: Yorba Linda CA
Originally Posted by Tom Piper
I think you are right about the surge tank being under pressure causing it to push outward, but this looks like the tank got too hot instead of too cold.
If I remember correctly, R12 will burn under the right circumstances and create phosgen gas.
Could it have ignited?
Tom Piper
If I remember correctly, R12 will burn under the right circumstances and create phosgen gas.
Could it have ignited?
Tom Piper
I think Tom's scenerio has validity. If you look at the edges of the blown out hole you will see that they are smooth. If it was caused by a jet of cold hitting the bottom of the tank the plastic would shatter (plastics get brittle when cold) and we would find sharp edges rather than smooth. Since the edges shown are smooth it is more likely the area was locally heated first and then the coolant pressure blew out through the soft area. This would also extinguish any flame from the R-12.
Since I'm not familiar with R-12. I have no idea as to whether the R-12 igniting makes sense. Thoughts from those familiar with R-12?
Also is there any signs of burning on the bottom of the tank and hoses?
I see some discoloration but that maybe from coolant.
Last edited by Daddy J; Jul 23, 2006 at 08:16 PM.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Originally Posted by bogus
I am guessing... lets say the AC line broke a little, letting a high pressure jet of gas make it's way out and essentually burn a hole into the plastic, causing the plastic to rupture.
Toss in a weak spot in the plastic... and BAM! You have a broken surge tank.
Toss in a weak spot in the plastic... and BAM! You have a broken surge tank.
Wrong-o, how about this one?Neighbors monkey gets loose (ya know, Speed Racer had one and it carried a wrench too), and started jacking with the guys car....
the tank with his wrench while gulping down some prime R-12-Made him nuts!! Well, no need to go into details here, you can fuigure out the rest. Trixie was ghey too, from what I hear. Oh yeah, back to the expansion tank.
Instructor
Joined: Mar 2005
Posts: 174
Likes: 3
From: Yorba Linda CA
Out of curiosity I looked up the MSDS on R-12. http://www.refrigerants.com/msds/r12.pdf
R-12 apparently isn't flammable, however the refrigerant oil is. Any thoughts about an oil mist flame causing this? I know this explanation is a bit "far out" but having a failure of this kind is "far out" in itself. Any chance of a mist flashback from the hot exhaust headers?
Thoughts?
Added: The "blended refrigerants" have possibilities too. Lord only knows what you are getting today with the recycling equipment
R-12 apparently isn't flammable, however the refrigerant oil is. Any thoughts about an oil mist flame causing this? I know this explanation is a bit "far out" but having a failure of this kind is "far out" in itself. Any chance of a mist flashback from the hot exhaust headers?
Thoughts?
Added: The "blended refrigerants" have possibilities too. Lord only knows what you are getting today with the recycling equipment
Last edited by Daddy J; Jul 23, 2006 at 08:54 PM.
Melting Slicks
Joined: Mar 2003
Posts: 2,472
Likes: 0
From: Toronto ONTARIO
Thought it would be interesting to note that My A/C stopped working years ago and I had my line break in the EXACT same spot as that. It literally looks identical to your picture. I didnt however have the coolant tank problem. I'll take a closer look at the bottom side of it, perhaps because it's not visible I havn't noticed.
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Safety Car
Joined: Feb 1999
Posts: 3,504
Likes: 4
From: Mexico Beach FL
Looking at the picture of the ruptured line, it looks like metal fatigue to me.
Interesting, someone else had it rupture in the same place -- must be pressure on the line or a lot of vibration in that area.
Or, another thought, is the cycling of the AC system causing the evaporator to go hot-cold-hot caused the problem.
Tom Piper
Interesting, someone else had it rupture in the same place -- must be pressure on the line or a lot of vibration in that area.
Or, another thought, is the cycling of the AC system causing the evaporator to go hot-cold-hot caused the problem.
Tom Piper
Last edited by Tom Piper; Jul 24, 2006 at 12:37 PM.
Pro
Joined: Apr 2005
Posts: 590
Likes: 0
From: Boynton Beach, FL
The tank failure was clearly heat or chemical related, i.e., internal blow out with smooth melted edges. Something melted or softened the plastic until the internal pressure blew out the reservoir. Possible causes 1) oil in refrigirant flashed and melted or softened plastic 2) refrigirant or refrigirant oil reacted with plastic chemically to soften it, 3) refrigirant and oil at failure point in AC line was under pressure at temperature. Temp and pressure ? but I know it had to be high. A jet of heated oil/refrigirant from a pin hole could easily have melted a hole in reservoir. 
Once an engineer, always an engineer.
Larry
Once an engineer, always an engineer.Larry
Drifting
Joined: Feb 2002
Posts: 1,952
Likes: 2
From: Little Rock Arkansas
How about if the electric water pump wasn't working... Ransome sent me an email earlier that said: "Did you perhaps pull the fuse out of the electric water pump?" D'OH!!!! I still can't imagine it exploding like that, not to mention he didn't say anything about it overheating but looks quite possibly like I may be the culprit. 
-Jeb
-Jeb
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
R12 at normal atmosphere's is around -32. Since it blew out at the low side (had it gone at the high, there's usually a nasty hole in the hood), it was probably around 36 to 40 degrees (assuming pressures of 28 to 32 psi) before it hit ambient and dropped to whatever pressure you were above sea level. That immediately flashed it to well below freezing (and it's why you're suppose to wear protective gear when you work around this stuff). Any a/c line will fatigue if you accidently bend one (and it's easy enough to lean on that Evaporator outlet and do that), but it looks like yours went at the weld. That's usually from moisture in the system which gets there if it's not topped off correctly. I would check Bulletins, NHTSA web site for any similar problems - otherwise a Chemical Engineering Firm could probably analyze any oil left in your Drier though it was also contaminated when the line snapped.
Thread Starter
Melting Slicks
Joined: Jul 1999
Posts: 2,875
Likes: 0
From: Olive Branch (Memphis suburb) MS
Cruise-In II Veteran
Still not 100% sure exactly how it happened, but it was overheating. The digital temp ready was showing a constant 178, but after I heard the pop, the analog gauge was close to being pegged. I need to check, but does the same sensor feed both gauges? The evaporator core actually looked pretty good for being 14 years old. 
Burning Brakes
Joined: Jan 2002
Posts: 1,228
Likes: 1
From: Dallas Texas
Originally Posted by Ramrod92
does the same sensor feed both gauges?
I also had the same fatigue failure on my evap. core. I was pulling on the dryer too much when I was working on it and it snapped in the same place yours did.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
That doesn't look like a stock core unless GM eliminated the foam filter. It's obviously been leaking, so I'm assuming somebody's been topping it off. Get air/water in it and the mix is highly corrosive.
Thread Starter
Melting Slicks
Joined: Jul 1999
Posts: 2,875
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From: Olive Branch (Memphis suburb) MS
Cruise-In II Veteran
I bought the car new and that's the orginal core. I don't recall ever having to charge the system. It always did a good job of cooling the interior down. 