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6 Posts
Discussion Starter · #1 ·
Recently picked up an 03 Duramax and am slowly fixing all the things wrong with it.
The coolant bypass valve above the thermostat (#7 in this diagram) has a hose that goes up and to the back, mine has a hole in it.
Whats that hose part number?
I cant find the hose in any diagram.
Or if you could point me to the diagram that would be helpful. Didn't see it on

Premium Member
26,484 Posts
just use bulk coolant line and hose clamps.
That's a coolant return line from the turbo.
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