AOS INNERDS

Thought some of you may enjoy what the insides of an AOS look like. Here it was before and you can see where it was leaking antifreeze. Here is inside the main body, it has two cavities. The large cavity on the right has a funnel at the botton to help the oil pulled out of the air drain back in the crankcase. This is the business end of the AOS, there is a lot going on in here. On one side you have a heat exchanger that the coolant runs through to heat the area of the diaphragm. I guess this keeps the oil at temperature so it flows better. The other side has a diaphragm with springs that allow air to move from one cavity to the other depending on vacuum load. The diaphragm has two sets of springs for some reason.

Nice pics. I have never seen a AOS, let alone the inside of one. Man, I just looked at the second pic again and I can't believe you pulled all of that change out of there. No wonder it was leaking!

So...overall thoughts on the job (in progress?), time taken, did you lower the engine some, etc etc? I'm trying to work up the courage to do mine.

I obviously missed your post in a previous thread : "Just finished. Total time about 6.5- 7 hours. About an hour was spent just cleaning parts, the inside and outside of the main intake, the t-body crossover tube and the t-body itself of all the accumulated oil residue. I would say a good independent who has done this before could do this in much less time, but they are not going to clean everything as they go. If you have your trans out for any reason please have them fix this at the same time as it would be dumb not to do this as the part is $104 from Suncoast, my car has 76k. Here are some observations that I have not read anywhere and may be specific to my AOS failure since mine was coolant related, but I am also assuming it was internally blocked. I am going to cut it open to see. 1. My air injection pump no longer whines like a supercharger, apparently the AOS was blocked causing it to either cavitate or be under back pressure. So if you are experiencing a loud air pump it may be the AOS. This was a total surprise. 2. If you haven't changed the plastic water coupling for the AOS near the alternator you need to. This thing disintegrates like nothing else I have ever seen. It literally turns to dust when you try to remove whats left from inside the hoses. My opinion is this part is going to cause more and more trouble by bursting as these cars get older. If I keep the car a long time I'm swapping to brass. I did not lower the engine to gain more access, but it could end up being necessary depending on the size of your hands or available tools and no doubt it could make things easier. You have to have a lot of patience and dexterity to hold a 7mm wrench in a 1 inch size opening on the backside to undo the big clamps on the rear crossover tube. The hardest part of this job by far is the last intake bolt. You have to make up the perfect set of 10mm socket and extension and wish it on the bolt. If you have ever seen a vet with their hand up a cows ****, that is what its like because of the distance to the bolt, the limited room to work, and the inabilty to see what you are doing. The torque spec seems to be 7.5 ft/lbs for the intake bolts. I was able to do the first 5, I just couldn't get my 1/4 drive inch/torque wrench to fit with my available extensions, it was either too low or high to fit. Parts needed including the AOS, 1 gallon of Peak 50/50, 1 worm clamp for lower AOS bellows, 3 small worm clamps for 2 water lines on AOS and 1 at the water coupling by the alternator, the 3 intake gaskets, the t-body oring, and that stupid plastic coupling I referred to earlier. I recommend the t-body oring as it seems to have a memory and was flat as a pancake inside the housing. The new one stuck out a bunch after installation for a good sealing surface. Big thanks to Ivangene who helped along the way on this thread and other previous posts of his. I will try and do a full write up for everybody to enjoy. This pic shows where mine was leaking, apparently the plastic cracked at the bottom on the round part letting the coolant slowly leak out. It had been doing this quite a long time from what I can tell."

This is an informative post, thank you, for taking the time.

Thanks for posting the pics. Interesting! I've always wondered what makes these AOS "tick"!

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I offten wondered why its there... I know what it does. But do any other cars makers havet his pesky thing?