Water Pressure Bouncing!
05-07-2025 | 12:27 AM
#12
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From: Germany
Test drove her yesterday without Thermostst.
No fluctruating Water press. Idle 3psi, went up to 4200rpm @17psi. Engine cold, Manifolds hand warm.
I'm wondering if the thermostat was bad or if the fluctruating comes back with the new thermostat.
No fluctruating Water press. Idle 3psi, went up to 4200rpm @17psi. Engine cold, Manifolds hand warm.
I'm wondering if the thermostat was bad or if the fluctruating comes back with the new thermostat.
05-07-2025 | 01:33 AM
#13
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35 is to high. With pressure getting high the water is not getting out of the engines fast enough. You could end up with intake or head gasket problems. I had this problem with my boat. Mercury had a solution and put out a service bulletin because of high water pressures. The solution was to put set screw in the side pickups on the bravo drives. My top 3 hole are plugged and the dropped my pressure down to 15-20 psi running wide open and 10-12 cruising.
I would try a new 160* OEM thermostat first. If it is still bouncing, I'd drill a 3/16" hole in the tstat and test again.
05-07-2025 | 04:14 PM
#14
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Drilling a weep flow hole in the thermostat, and getting some water flow in the engine as it heats up is good to have.
Cummins 5.9 engines has this weird temp fluctuation as the thermostat cycles. It's unnerving. I think Dodge changed the gauge to respond less.
Cummins 5.9 engines has this weird temp fluctuation as the thermostat cycles. It's unnerving. I think Dodge changed the gauge to respond less.
Last edited by Tartilla; 05-07-2025 at 04:50 PM.
05-09-2025 | 12:04 PM
#15
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Tried today. I took the original thermostat, drilled 2 holes 1/8. The water pressure does not fluctruating anymore but she would peg the gauge. Reved 4500 and had 35psi. Pulled back the stick then.
so whats the best solutuon now? Bypass?
so whats the best solutuon now? Bypass?
05-09-2025 | 09:10 PM
#16
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From: Omaha/LOTO
You would need to either reduce the amount of water coming in or get a pressure relief valve to get it out faster.
05-23-2025 | 01:12 AM
#18
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I would like to install a pressure relief valve. Whats the best place to tee in? CPPerformance has the T in 1-1/4 inch. Looks like it should be between seawater pump and oil cooler? I weld the T by myself so i can size it how i like it. so whats the best place to tee in?
Thanks!
Thanks!
05-23-2025 | 04:24 PM
#20
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From: BC
