On my 93 W250, 5.9L can't get the boost over 12 PSI.
I have boost tested through the turbo and have pressurized it up to about 25 PSI on the compressed air supply, and it holds about 22 PSI on the boost test gauge.
I have 2 or 3 tiny bubbles coming through the rubber connections to the intercooler, and when I release the airline and cap the supply, it slowly drops about 1/2 lb per second, which I have read is expected, so I don't think I have a boost leak.
Could the turbo be worn out and not up to making more than 12 PSI?
Is there anything else I should check before replacing the turbo?
Thanks in advance for any help
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