So this weekend I installed my new FMIC and reloacted the battery. I took the car out for a test run and noticed my temps creep up slowly but surely (Griffin rad, Blitz FMIC, not ducted yet). Long story short, I pull the car over at about 205F in block, and notice that I have ZERO pressure in the upper rad hose. I figured it was a stuck thermostat (due for replacement this summer) so I quickly run to Advance and get a stant Tstat (I know OEM is better, but I needed to drive the car 100 miles home that night). Installed Tstat, started car up, and same thing happens. Turns out that I still had zero pressure and the car quickly got up past 200F. Took Tstat out and started car and still no pressure. I figure this has to be the water pump, despite it not leaking at all out the weep hole.
Rad was flushed 5 months ago, and car has run very well (and cool) until Sunday. Has anyone else experienced this kind of failure? I always read that our pumps were pretty good at announcing trouble via the weep hole.

Also: no coolant discoloration, or bubbles with engine running, and no leaks out of heater core hoses, BAC, Turbo feed/return, or primary hoses.

Thoughts? There has been a bit of a strange whirr sound all winter, but I was pretty sure it was the PS pump.

edit: did not drive car home, obviously

 

I'm pretty sure water pumps can go bad without bleeding coolant out the weep hole. In fact I'm pretty sure I had that very thing happen to me (it's tough to remember because it was several years ago).

 

Most of the pressure in the system comes from the coolant heating up and expanding, not from the water pump. If the system can't hold pressure and you're sure you have no leaks, then you probably have a faulty pressure relief cap on the radiator. Replace it with a new one and see what happens.

 

Thanks NZ, I'll check that out too.