Some cooling system questions
 

My water pump recently failed (never had a bearing on a water pump fail this aggressively: it was really loose).

Replaced with a Pierburg pump and Wahler low temp thermostat. The Wahler proved to be defective (first installed and measured in situ, then did a stovetop test), and it wouldn't start to open until 180-185, awaiting a replacement.

Also replaced the serpentine and will replace the tensioner pulley (awaiting delivery) as it is not turning totally frictionlessly.

In the meantime, I removed the 180 degree thermostat from the original housing and reinstalled the housing sans thermostat in order to run some coolant flush thru the system for a while. I filled the system using the vacuum/evacuation/suction method.

So some questions:

1. When I evacuated and then vacuum pull filled the system to flush it, I only got about 4 gallons out and just about the same back in; as the spec is more around 5 gallons, do I have some residual coolant hiding somewhere (and maybe also some air?)? I did the complete step-by-step draining process: removed drain plug, pulled all the appropriate hoses with the car level on jackstands, turned on the heater to drain the core, etc.

2. When I first filled the system with water+flush, I could've sworn that the fans kicked in at about 190 when the car was on jackstands, I have since run the car (without thermostat) on the road, getting the coolant up to right at 200 (OBDII measured) with no fan action. Do I have a fan, resistor or some other issue?

3. My new thermostat (a Motorad low time this time) hasn't arrived yet, so is it OK to leave the flush (Prestone yellow bottle) in the system for a couple of days?

Thanks in advance for any insight.

When I did my thermostat recently, I found I had to get car tilted nose-up several degrees in order to get all the fluid out of the front end. A lot (more than a quart, less than a gallon) was hiding in the radiators/hoses as well. (2002 3.2L, so has a center radiator).

I just had my water pump changed and thermostat, mechanic told me i would probably have to top off next day when it cooled. And it was low, got the low fluid blinking light took maybe 2 liters to top it off.