I thought about something(I know bad things happen when I think) but could you drill a hole in the thermostat, tap it and put a bolt or something in there to burp the system I mean it is higher than anything else right?

Honda's have bleeders. So do cummins diesels. And most domestic straight sixes SHOULD have them. Sounds like a good idea.

Or how about changing the thermostat cover to one that has a radiator cap in it? I've got one like that on my hatchback. It came off a fuel injected RX7 and the bolt pattern etc matches the Subaru perfectly. There's probably other cars out there using similar 'stat housings but the mazda is the first one I noticed that served my purposes.

ya, but what about my idea? would it work? has anybody done it?

I have drilled and tapped the T-stat housing on other makes to install an additional temp gauge. Not much meat there, so you have to be careful in doing so. Think your idea is a good one, but would use a pipe plug instead of a bolt. Better seal at threads that way.

I guess I have to ask why?

 

I've never had a problem burping my system as it is.

 

Benefit vs. Investment ?

just to be easier.