Coolant system bleeding
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Coolant system bleeding
Hello, I’m currently trying to bleed my coolant system after replacing the oil cooler (heat exchanger). I can’t seem to get a good bleed causing the car to start puking coolant out of the expansion tank.
What I’ve tried:
Regular, open both bleed screws. Bottom first, then top, with a cold system and getting bubble free streams. Closing them. Closing expansion tank and running till warm. (Coolant pukes)
Repeated above procedure, but placed a vacuum tester after closing the bleed screws. Can’t seem to pull more than 25 inHg, but it did allow me to find a dissected heater hose which I replaced both hoses before and after the T-piece for the return hose. After replacing those hoses it held a vacuum at 20ish inHg, but still wouldn’t pull more than 25mmHg possibly due to coolant level rising and getting sucked into vacuum tester. Filled system under vacuum. Closed system and ran till warm (Coolant pukes)
Repeated first and second procedure, closed system, ran till warm and cracked both bleed screws w/ thermostat open. Lower bleed screw had steady stream. Upper bleed screw had no stream, but quickly caused coolant pukage (kinda expected it)
Repeated First procedure, kept system open to keep an eye on coolant level while thermostat opened. Thermostat opened, sucked some coolant down, then it quickly refilled the expansion tank on its own, then proceeded to puke again (also kinda expected)
Through all attempts, the coolant temp has never gotten above 200°F
Besides the oil cooler replacement, I’ve also replaced:
Entire cylinder head. Why: Spark plug threads were stripped in C2 when I bought it. Used ARP head studs and new headgasket. (Thought oil in coolant was the head, later found out it was the oil cooler) Has great compression.
Water pump
Radiator
Timing gears/chain
Prior to head replacement: 15% reduction pulley w/ colder spark plugs and DDM CAI.
Post head replacement it was exhibiting these symptoms, but much less severe/after spirited driving. I attributed it to the oil cooler being cracked
So my questions are: What am I doing wrong? What am I overlooking? Is this bigger than not getting an adequate bleed? Could I still be missing a small leak somewhere causing pressure to escape the system causing the boil over?
What I’ve tried:
Regular, open both bleed screws. Bottom first, then top, with a cold system and getting bubble free streams. Closing them. Closing expansion tank and running till warm. (Coolant pukes)
Repeated above procedure, but placed a vacuum tester after closing the bleed screws. Can’t seem to pull more than 25 inHg, but it did allow me to find a dissected heater hose which I replaced both hoses before and after the T-piece for the return hose. After replacing those hoses it held a vacuum at 20ish inHg, but still wouldn’t pull more than 25mmHg possibly due to coolant level rising and getting sucked into vacuum tester. Filled system under vacuum. Closed system and ran till warm (Coolant pukes)
Repeated first and second procedure, closed system, ran till warm and cracked both bleed screws w/ thermostat open. Lower bleed screw had steady stream. Upper bleed screw had no stream, but quickly caused coolant pukage (kinda expected it)
Repeated First procedure, kept system open to keep an eye on coolant level while thermostat opened. Thermostat opened, sucked some coolant down, then it quickly refilled the expansion tank on its own, then proceeded to puke again (also kinda expected)
Through all attempts, the coolant temp has never gotten above 200°F
Besides the oil cooler replacement, I’ve also replaced:
Entire cylinder head. Why: Spark plug threads were stripped in C2 when I bought it. Used ARP head studs and new headgasket. (Thought oil in coolant was the head, later found out it was the oil cooler) Has great compression.
Water pump
Radiator
Timing gears/chain
Prior to head replacement: 15% reduction pulley w/ colder spark plugs and DDM CAI.
Post head replacement it was exhibiting these symptoms, but much less severe/after spirited driving. I attributed it to the oil cooler being cracked
So my questions are: What am I doing wrong? What am I overlooking? Is this bigger than not getting an adequate bleed? Could I still be missing a small leak somewhere causing pressure to escape the system causing the boil over?
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