(2014) ISX15 coolant help!

[Rawze]

(10-16-2020 )GhostHauling Wrote:  Okay guys I ran the test twice at two different places both tests as follow the tool help psi at 1to2 psi at start it took 12 min for psi to build to 8to9 psi up to 20 min it stayed right around 10 psi never over. During test I checked for leaks everywhere I couldn’t find anything however during second test around 15 min my truck idled up to around 8k rpms I can hear turbo (like many peterbilts I’ve heard idle up while sitting for long periods) however my truck didn’t idle back down to normal and now I’m sitting again and it’s idled up again at 790rpms and after 15 min it’s not idling back down it’s almost as if it’s about to start a regen but it doesn’t I realize this is unrelated but this truck since I’ve had it has never idled above 600 but I never idled it long

Except for the idle up issue, what you describe sounds about normal as far as pressure buildup goes.

The idle speed varying on its own could be a few things.

You need to ensure that engine passes a rail leak test first and foremost...

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to ensure fuel is not getting into the cylinders and causing the rpm to climb... a bad injector that can allow engine to idle up is going to cause all sorts of other issues.