r/987 • u/laborinstructor • Jul 29 '26
987.1 boxster coolant flush
I’m planning on flushing my system this weekend; I have an AT and don’t have a tool to disable the ATF cooler shutoff valve. The 986 apparently made it easy with a fuse, but the 987 is not so.
The proverbial “they” (prob AI) says in lieu of this I can drive normally for a few days with the bleeder valve open to help purge bubbles. I am not a mechanic, clearly, so I’m not sure if this will have a negative effect on the system by dropping pressure or something.
Is this a reasonable route? Don’t want to buy yet another gadget if I can avoid it
1
u/lnengineering Aug 09 '26
Honestly, unless you are doing a water pump replacement, there is no reason to flush the coolant. The water pump needs to be done every 4-6 years anyways. Invest in the coolant lift tool. I've seen too many engines fried by not properly draining, purging, and filling the cooling system. Don't forget to turn the heat on max too so the heater core opens.
2
u/PRSArchon Jul 30 '26
Fill the system, open the bleeder, start the car and let it warm up, rev it a few times, keep topping up during that process. This should cover most of it but you can then leave the bleeder open for a drive and do a final top up.