2009 International with DT466. Bus has air brakes. The coolant system is steadily building pressure upon start up and continues until it pushes out the 15psi cap. The coolant reservoir actually split along the seam. Don't know if that was a result of age or directly from the over pressure issue. Replaced the reservoir. With cap off and engine running at idle everything seems fine. Step on the gas and bring rpm's up and there is a noticeable increase in coolant return and frothing/air that quickly overflows out of the top of the reservoir. There's no coolant in the oil. There's no oil in the coolant. There's no white smoke coming out of exhaust. I'm leaning towards the air compressor being the culprit. Does anyone know how much pressure a bad air compressor would or could put into the coolant system? If it is an issue like bad injector cups or a head gasket how much pressure would or could those cause? Thanks for your thoughts.
We've had air compressors pressurize the cooling system before. Easy enough to replace the whole unit before taking apart the motor. If I would put money on it, I'd say replace the air compressor.
I've run into this before. To determine if it's the compressor or the engine, bypass the cooler lines to the compressor. Hook up a garden hose and attach that to the coolant ports of the compressor to keep that cool. If you're still building pressure, it's something with the motor. If the problem goes away, it's the compressor. Hope this helps.
I have 26 MF DT 466's, In my experience liner protrusion caused head gasket failures have been the issue. The excessive pressure will take out your EGR coolers as well if the problem persists. If you're lucky it's just a head gasket.
easy air compressor trick , supply the line with 120 psi(1/4"line to dryer) to unload the unloader and it will not build up pressure it will just bypass , and these were also bad with liner protrusion
OEM trained in wiring and all engine platforms for over 20 years
Air in system is the first thing to check; re-bleed and see if the problem goes away. The system needs to be fully closed (no venting) to function properly.
excessive pressure in cooling system
Posted - 08/06/2021 : 09:01:30 AM
