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Agree it may be rare, but it did happen. Maybe I should submit it to Ripley Believe it or Not? I had posted about this a while back (see here: Can coolant mix wth oil inside the turbo?) and ksw92_mk2 offered an explanation in that there could be a leak between the oil and water chambers of the turbo. Since the coolant pressure in the turbo is much higher than the oil pressure at the side where the oil side drains into the oil pan (essentially atmospheric pressure), coolant could force itself into the oil passage (but hardly the other way around) and coolant ends-up in the oil pan but. Made sense to me. And, my problem disappeared as soon as I replaced the turbo. Coolant pressure after turbo swap held just fine.
 

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Did you disassemble the center section and pressure test the center block? that would have driven me nuts not knowing!
Not sure I follow the question. I came to the conclusion that it was the turbo and not the head/block that caused the leak. During my troubleshooting (doing compressor test, leak-down test and pressure test), I started to suspect the turbo as I could see trace of coolant coming-out at the flange between the turbo and down-pipe. Of course I suspected the head gasket or a crack in the head but, I was also in disbelief that the head really could be the cause of my demise as I had recently replaced it (a machine shop had fixed-it up for me so I know it was good), and I wanted to prove to whether it was the head or the block. So, I removed the exhaust manifold and then pressure tested the system again, thinking I would see coolant come-out the exhaust ports. But then I saw more coolant coming-out at flange between the turbo and the down-pipe. I thought it was really weird as I did not think that it would be possible for coolant to leak into the oil and also down the drain through the down-pipe. That's when i posted and asked questions. But once I put in my old turbo that I had laying around, it stopped my problem and I have not had any low-coolant messages ever since (3-years later) so it must have been the turbo. Watch, I will probably be jinxed and report a low-coolant problem tomorrow!
 

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Not sure I follow the question. I came to the conclusion that it was the turbo and not the head/block that caused the leak.
What I was wondering was after you had the turbo out and on a bench if you tried to connect up to the water ports and pressure test the turbo center. There should be no passage between that coolant and anything else. It's just water in and water out. The only way that it would be going elsewhere would be a crack in the cast iron. (IIRC they are cast) and that would be extremely unusual!

I'm more curios than anything else because that would be the first time I've heard of a center section failing like that. Often they are destroyed when the bearings are destroyed or the turbine shaft breaks. But I've never heard of that kind of coolant leak.
 

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Ohh... (feel stupid now) but I did not read very well and saw the word “block” so I immediately thought you were asking about the block and the head. 🙄 But to answer your question, I did not test the turbo on the bench and I’m not sure I am smart enuf to jerry-rig that set-up anyway. But agree, should have done that! Since I had another turbo laying around, I just swapped them and tossed the old one once I realized that my dilemma had been solved. Oh well. I agree it seems rare but I did come across the same issue on another forum (not Saab), where a similar event happened.
 
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