B230FT Loosing Coolant

Hi all, have some Redblock issues. My B230FT is loosing a large amount of coolant. Pressure test on cooling system is great, compression test is great. Replaced all the cooling items, except the overflow tank and cap. Oil is not milky, but it does sizzle and crackle when I put a little amount on the manifold. No oil in the coolant. Recently replaced the oil cooler as well. Freshly machined head and new headgasket aswell. I honestly have no idea anymore. I can't seem to find any other threads with the same issues. Anyone got any other areas to check?

Is this a brick with an automatic transmission? Check the transmission dipstick. And soon. If the fluid is frothy, replace your radiator, do a transmission flush and pray that it isn't ruined.

Try the opposite process. Hook up your pressure tester to the system, don't pressurize the system, start the engine and watch the pressure gage on the tester. I had a scenario like this on a LT1 powered Z28. What was happening in my case was the head gasket was only leaking under really high cylinder pressure. It would put so much pressure in the cooling system the cap would let the coolant out while driving. If I ran a typical pressure test, the cooling system would hold 15 psi for 24 hours.

I had a coolant leak on a 85 245T. Did the headgasket and still had a leak or overheat issue. Pressure tested it as well and was ok. Then come out in the morning and had coolant around the exhaust manifold. Took that off and had a pinhole in the #4 exhaust port. Didnt show up in oil since it was going out the pipe.

2manyturbos said:

Try the opposite process. Hook up your pressure tester to the system, don't pressurize the system, start the engine and watch the pressure gage on the tester. I had a scenario like this on a LT1 powered Z28. What was happening in my case was the head gasket was only leaking under really high cylinder pressure. It would put so much pressure in the cooling system the cap would let the coolant out while driving. If I ran a typical pressure test, the cooling system would hold 15 psi for 24 hours.

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Ended up being this. Had a small nick in the head gasket and coolant was leaking through at high pressure and coming out the cap. Pulled the whole head to finally get my answer lmao.