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My Rx8 started puking coolant from the overflow tube and overheating temp rising very quickly to 105C at idle . I can see air bubbles in the coolant reservoir. I can also hear like a worn bearing noise coming around the alternator. Could a bad water pump pressurized the system to a point where air bubble form and puke out or is it coolant seal?
First thing to check is your cooling fans. Had a similar problem and that was the cause.
Cooling fans coming on at low speed 98c and high speed 102C.
I've change 3 radiator cap so far and still puke coolant. The overflow tube make a pressurized hissing noise, If I block the overflow tube with my finger pressure is released from underneath the radiator cap. When temp reaches 101C lot of coolant come out of the overflow.
Also notice and a hard acceleration cut that occur randomly at 6000rpm to 8000rpm.
The ultimate test would be an exhaust gas in coolant test, also called a block test. Anyone mechanic can do it. It'll confirm if you have a seal problem.
Pretty much what others said. Coolant bottle can crack as it ages(early RX-8s are 15+ years old at this point), and if there is a seal problem, you can either have a mechanic perform a block test or you can lend the tools yourself and do it(not sure if that's an option with COVID-19 around, though).
Cooling fans coming on at low speed 98c and high speed 102C.
I've change 3 radiator cap so far and still puke coolant. The overflow tube make a pressurized hissing noise, If I block the overflow tube with my finger pressure is released from underneath the radiator cap. When temp reaches 101C lot of coolant come out of the overflow.
Also notice and a hard acceleration cut that occur randomly at 6000rpm to 8000rpm.
Assuming your coolant overflow bottle in good condition, it could be a coolant seal. One way to know is if it’s puffing constant white smoke out of the exhaust. If it fails the Block test, you have a serious problem. The engine won’t blow up but it will slowly stop working altogether. There is an additive you can try but only would advise if you are NOT planning to rebuild the engine and instead replace it. It’s called Bar’s Stop Leak, this one specifically. Can’t say it will work for you but it has for others. May give you some extra miles and worth a shot if you aren’t rebuilding. Again, only try this if you confirm the issue is a coolant seal.
Assuming your coolant overflow bottle in good condition, it could be a coolant seal. One way to know is if it’s puffing constant white smoke out of the exhaust. If it fails the Block test, you have a serious problem. The engine won’t blow up but it will slowly stop working altogether. There is an additive you can try but only would advise if you are NOT planning to rebuild the engine and instead replace it. It’s called Bar’s Stop Leak, this one specifically. Can’t say it will work for you but it has for others. May give you some extra miles and worth a shot if you aren’t rebuilding. Again, only try this if you confirm the issue is a coolant seal.
No white smoke ..but there are bubbles in the coolant reservoir. Could a failed coolant bottle cause bubbles?
I'll get the coolant tested for combustion gas. If its a failing coolant seal then will rebuild the engine
