I thought it was lack of through bolts that results in a floppy compressor mount, stressing the perimeter crimp seal which leads to the blow out?

You can see the blown seal in this pic on the perimeter of the body:

Attached Thumbnails

 

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

So are you saying that with R12, you don't have to do as good a job and can have some leaks? Whereas with junk refrigerants, you have to do a better job?

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Only 2 bolts? I don't like that at all with the compressor "hanging" with just 2 bolts on top. Are the 2 bolts through bolts?

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

You obviously don't understand the downside to a BLEND refrigerant. I have explained this at length in posts DOZENS of times, but what's once more?

The blend consists of multiple, usually two, different elements. When a leak takes place, of which most leaks are small, one element leaks at a faster rate than the other. The only way to put it back into proper balance, is to completely recover and dispose of the recovered contents.

You can't recycle it as you can a legitimate refrigerant because it is out of balance, so it cannot be recycled. If you do things legally there will also be a disposal fee for what you have recovered. Of course, most people don't care, or they wouldn't be using such a refrigerant in the first place, so I expect that they simply vent it to the atmosphere while no one is watching. To summarize, they pay a hefty disposal fee OR violate Federal law. It's that persons choice.

THEN once the system is empty, they can repair their leak, evacuate and recharge unable to use any of the original refrigerant.

The DIFFERENCE with a legitimate refrigerant is that you can recover the refrigerant, repair the leak, evacuate and recharge with your original refrigerant plus however much extra is necessary to complete the charge. If you're lucky and find a leak that can be fixed without recovering the charge, you simply top it off. In neither of these scenarios do you pay a hefty disposal fee OR violate Federal Law.

It is quite obvious that a system should be as tight as you can get it regardless of refrigerant used. The difference in the consequences of a leak, which can happen to any system, is as described above.

Does that answer your question?

Liquid Slugging:

This is a result of trying to compress liquid in the cylinders.
That liquid may be either refrigerant or oil or more likely a combination of both.
In the case of air-cooled compressor, any liquid being returned to the compressor comes directly into the cylinders.
On a suction-cooled compressor, slugging is a result primarily of refrigerant migration into the oil on the off cycle.
Upon start up the lowering of crankcase pressure causes a violent explosion that carries quantities of refrigerant and oil into the cylinders.

The results in either case are:

#1. Blown gaskets - head or valve plate gaskets
#2. Broken reeds - either or both
#3. Loose discharge valve bolts - stretching or stripping threads
#4. Broken rod or crankshaft - depending on the quantity of liquid in cylinders

Funola,
the compressor has 4 holes with which to bolt to the car and 2 ports for refridgerant. (I'm only doing it this way to walk myself through it mentally...you have dissassembled one all the way so you know this way better than I do).

With the ports down, the compressor connects to the vehicle using the top three bolt holes. the bolts thread on the rear of the compressor and do not go all the way through to the side with the clutch on my SD. there ends up being one bolt hole underneath the ports that is unused.

I took a long bolt with a nut and cut it to fit exactly as to not interfere with the clutch but to essentially hold the compressor together.

If I could find replacement bolts that would go all the way through and thread to the clutch side of the comp for all four holes, I would do it.

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77' 300D, "Cartman" SOLD @ 150K (didn't know what I had)
83' 300SD, "The Superdon" 325k+ @ 28mpg
95 E320 wagon, "Millennium Falcon" 231k+ @ 24 Mpg
95 E300D, "Sherley" 308k @ 33.69 Mpg, currently anticipating a head
99 Suzuki Intruder "Trudy" @ 45 mpg

Roy,

I immediately thought of slugging also, but as I understand, vstech did this one both times. He has forgotten more about refrigeration than I'll ever know. Anything can happen to anybody, but I can't imagine him setting up a slugging situation, not once but twice.

If that were the cause, however, it would explain alot.

The picture shows a compressor that has been exploded by slugging.

Working at Visteon, Sanden, etc, I have seen to many samples/examples of this issue.

ok, so we didn't put too much freon in. I just checked my last ac rebuild and we put in 2.5lbs of r134a. which is 85% of 3.3lbs.

the first time we replaced the comp we did a flush. and put the in the exact amount of oil. 2nd time we replaced the comp we put in less than half the required oil (b/c we didn't flush it. The lines were still covered in oil from the blowout).

3.3 of r12 exactly and not enough oil to cause (from my research) the slugging.

the only thing left I can think of is that the compressor's I've been putting in were poorly manufactured.

I want a harrison compressor. Mommy, Can I have a new harrison compressor?

__________________

77' 300D, "Cartman" SOLD @ 150K (didn't know what I had)
83' 300SD, "The Superdon" 325k+ @ 28mpg
95 E320 wagon, "Millennium Falcon" 231k+ @ 24 Mpg
95 E300D, "Sherley" 308k @ 33.69 Mpg, currently anticipating a head
99 Suzuki Intruder "Trudy" @ 45 mpg

What were the circumstances of when it blew. Did it happen immediately after the recharge? Did you get all of the flushing agent out? Was there a good, long vacuum applied to the system. Heck, I am just down the road in the north side of Winston, and I have an a/c vacuum pump. If you want, the offer is here if you want to bring it down and check it out. The vacuum pump is one of the major players in successful a/c work. I also have another R4 compressor, that does not have alot of miles on it if you are interested.

I had a new one fail like that, there turned out to be plenty of debris left in the system from the previous failure. I suspect the expansion valve was clogged and the compressor over pressurized itself.

Yeah, vstech had the biggest coolest vac pump I've ever seen. Not only did we completely flush it with AC flush, but we pressurized it to 150lbs with nitrogen, then we vacuumed out the nitrogen. I definitely had a "my ac is cleaner than yours" complex for a while. right up until the comp blew up.

I'm 100% certain that it was done correctly. That leads me to believe that either that something was changed by a PO that makes my system not stock, or the four season's compressors are truly garbage.

My expansion valve is new...and the nature if the failure doesn't suggest debris (that is conjecture but if it blew the seal, that means that something else heald fast and it was the seal that blew instead...leaving a clean system)

__________________

77' 300D, "Cartman" SOLD @ 150K (didn't know what I had)
83' 300SD, "The Superdon" 325k+ @ 28mpg
95 E320 wagon, "Millennium Falcon" 231k+ @ 24 Mpg
95 E300D, "Sherley" 308k @ 33.69 Mpg, currently anticipating a head
99 Suzuki Intruder "Trudy" @ 45 mpg

Were the compressors new or rebuilds? I replaced mine with a new one from NAPA. It was in a NAPA box, but Compressorworks? was what was on the label. I guess a defective expansion valve could let too much refrigerent in the in the evaporator, not fully vaporize, and let some liquid refrigerant go back in the suction side of the compressor. That could definately cause damage it it was too much liquid going in. Someone correct me if I am wrong here.. Like I said in a previous post, my new expansion valve (not Behr btw), was stuck shut, and I lost all of my r12 having to replace it.

Both the R4s I've installed had oil in them. A good bit, in fact.

Did y'all drain and flush that before adding the proper oil fill, or did you figure out how much was there and add the required amount?

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1998 E300 +310,000K
1996 E300 +460,000K

I looked at both my Harrison (on the floor) and the CompressorWorks (on the car). Externally they appear to have the same construction as the Four Seasons, so I wouldn't think there'd be too much "beefing up" of the construction to stop a blown seal.

I also checked the holes and didn't see threads on the clutch side of the holes, so I don't think the bolts are meant to go through and serve any sort of retention function. The only bolt that goes through is the fourth "manifold retention bolt" and that's not used on the SD, apparently.

I have done some research on expansion valves, and I'm not proclaiming to know anymore than I've read, but the description says that expansion valves are matched for the refrigerant they're supposed to use by having a bulb filled with that refrigerant.

Throwing out an idea here: maybe it's possible for an R-12 TXV to work okay with 134a, but going backwards doesn't work? If that's a new TXV with 134a in the bulb, it could open/close on the 134a schedule instead of R-12 and dump too much liquid R-12 into the evaporator which then gets pulled into the low side.

Other ideas: assuming the same guy buys the same compressor from the same shop twice, the odds that two of them blow are greatly increased if that lot is faulty. It may be dumb luck coupled with a bad production run from Four Seasons. Do you have the old one and are there any lot markings on it?

Or - was the same clutch re-used? Any chance the clutch seized and cause some non-radial torque and helped rotate the front of the compressor away from the mounting bolts on the back?

Or - were the correct spacers used in the install(s) to get the compressor/clutch face square to the belts and secure to the brackets? If not, you could have some loading on the compressor that stresses the rear mounting bolts.