Oil blockage question on 951
08-13-2007, 09:39 PM
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Oil blockage question on 951
I have heard that a pipe connected to the turbo on a 951 can get blocked up because of oil hardening (coking) over time. Thing is that I cannot figure out which pipe to check -- is it the steel braided tube or another tube? 
08-13-2007, 09:58 PM
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Does anyone know where this goes??
Part 6 is P/N 951.123.083.00 -- I can see from the diagram that one end connects to the turbo/left engine mount. Where does the other end (top of tube) go?? Thanks. 
08-13-2007, 11:38 PM
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Thanks ST -- this is the black unit that mounts to the block with the (yellow) oil fill cap. I replaced the o-rings on the AOS and the oil system was super clean thanks to lots of regular and frequent changes of Mobil 1. I was concerned that this tube might have some coking blockage per a somewhat helpful professional.
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08-14-2007, 12:06 AM
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No, that vent line to the AOS will not block up with coked oil, and unlikely it would plug up with anything else.
The braided SS line coming in the top of the Turbo is the feed line, so that will not be plugged with coked oil. The drain goes down through the motor mount and large banjo line into the oil pan - probably very unlikely that this line would plug.
Did your little electric water pump fail? If not, then there is little reason to suspect any oil coking. And if you do have a heat/cooling/lubrication problem within the turbo that does cause the oil to burn/coke, it will be likely be localized within the turbo bearing housing.
Do you have some problem/symptom, or are you on a witch hunt?
The braided SS line coming in the top of the Turbo is the feed line, so that will not be plugged with coked oil. The drain goes down through the motor mount and large banjo line into the oil pan - probably very unlikely that this line would plug.
Did your little electric water pump fail? If not, then there is little reason to suspect any oil coking. And if you do have a heat/cooling/lubrication problem within the turbo that does cause the oil to burn/coke, it will be likely be localized within the turbo bearing housing.
Do you have some problem/symptom, or are you on a witch hunt?
08-14-2007, 01:25 AM
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Originally Posted by Oddjob
No, that vent line to the AOS will not block up with coked oil, and unlikely it would plug up with anything else.
The braided SS line coming in the top of the Turbo is the feed line, so that will not be plugged with coked oil. The drain goes down through the motor mount and large banjo line into the oil pan - probably very unlikely that this line would plug.
Did your little electric water pump fail? If not, then there is little reason to suspect any oil coking. And if you do have a heat/cooling/lubrication problem within the turbo that does cause the oil to burn/coke, it will be likely be localized within the turbo bearing housing.
Do you have some problem/symptom, or are you on a witch hunt?
The braided SS line coming in the top of the Turbo is the feed line, so that will not be plugged with coked oil. The drain goes down through the motor mount and large banjo line into the oil pan - probably very unlikely that this line would plug.
Did your little electric water pump fail? If not, then there is little reason to suspect any oil coking. And if you do have a heat/cooling/lubrication problem within the turbo that does cause the oil to burn/coke, it will be likely be localized within the turbo bearing housing.
Do you have some problem/symptom, or are you on a witch hunt?
My paranoia is that I now know exactly how many hours you can spend on these cars and want to cover any "easy" items now that may bite me in the butt later. A respected shop in Seattle told me about the "vent pipe coking" issue when I took my car to them for a 2nd opinion post purchase inpection several months ago. Guess you can attribute the witch hunt to them because no one who is truly knowledgeable that I respect has brought it up.
08-14-2007, 10:53 AM
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Well, if you still have the engine torn down, at least all the top bolt-on bits, you certainly can check the breather/vent line, the oil supply line, and the oil drain line for any restrictions ("while youre in there").
I just went through a problem - excessive oil in the intake. Other than the turbo shaft seal and compression blow-by through the crank case, I also looked at the possibility that the turbo drain line was plugged, causing oil to push out past the turbo shaft seals. After checking into that, Im fairly confident that the drain line will not plug (unless something very unusual happens). Turned out to be a turbo shaft seal leak, on a relatively low mileage turbo.
I just went through a problem - excessive oil in the intake. Other than the turbo shaft seal and compression blow-by through the crank case, I also looked at the possibility that the turbo drain line was plugged, causing oil to push out past the turbo shaft seals. After checking into that, Im fairly confident that the drain line will not plug (unless something very unusual happens). Turned out to be a turbo shaft seal leak, on a relatively low mileage turbo.
