New thermostat is in, and i did a bunch of others things at the same time... too many variables.
Replaced thermostat
Rotated coolant bypass
Swapped Radiator Flow
"Purged" coolant line of air
Installed Seats
disassembled shifter assembly
Replaced the thermostat with, what I believe is, an updated version for the cobalt. This one opens @ 180*F... not sure what the last one was set to, but i imagine that the OEM thermostat might have been a bit higher given the info I have seen about default temps in cobalts.
Since I drained the system to get the thermostat replaced I went ahead and swapped the Radiator feeds as well.
Driver side hose # xxx
and passenger side hose # xxx
I simply reused the provided hose from DF to have the engine outlet, passenger side, feed the radiator at the top rather than the bottom.
I bought the above noted hose from local shop and routed the driver side hose to the bottom.
Purged the coolant line with the car tilted forward so that coolant would not trap any air while I filled the from the reservoir.
I thought long and fervently about how to do this single-handedly. which side to fill first, how to get rid of the air gap at the top of the rad....
I thought I could use the same technique as read before and using a blowgun to force the coolant from the bottom of the rad to the top and out the passenger side.
- With the car roughly level, I loaded up the driver side with one gallon of water until coolant dripped from the passenger side lower hose "joint"
- clamp the driver side hose to prevent further trickle out from the radiator, I used a large wood clamp, but simply stopping flow is all you need.
- having the trickle coming out of the passenger rail hose told me that the radiator is filled from the bottom to about where the lip of the passenger side hose meets the radiator. the air gap above that will get purged when forcing more coolant into the radiator
- Reconnect the passenger side lower hose to the rail hose to feed the engine outlet.
- Lower the front end of the vehicle and disconnect the small hose that leads from the engine outlet to the reservoir.
- I used the metal pipe in conjunction with a spare hose to point the overflow into a bucket
- you can also raise the rear to help with keeping the air from going back into the radiator.
- Finish loading the reservoir if the hose clamp has properly stopped flow through the radiator, the gravity potential will help.
- the slope created by angling the car will still fill with coolant if the driver side hoses are not fully clamped and coolant will flow out before the air is purged.
- I loaded the reservoir up to right below the overflow line and put the cap on hand-tight, which I used as a means to introduce compressed air to force the fluid later.
- at this point the radiator is partially filled to the brim, there is no air on the driver side of the system, & the only point open to the air is the line from engine to reservoir line.
- the reservoir could have fluid up to the point of the engine overflow point, but all that is necessary is that there is SOME fluid in there to act on the rest of the system.
- the driver side can be considered filled with coolant and the passenger side is all air waiting to be expelled
- Connect an air compressor, or other means to the engine overflow hose going to the reservoir
- the other side of this is coming from the engine, this hose should be going into a bucket or other container... sploosh!!
- don't let the coolant get too low in the reservoir, otherwise you are re-introducing air to the system...
- using short bursts I pushed the air from the top of the radiator down through the hose and burped the system in one go.
- on the downside, any remaining air may very well be left in the system
- on the upside, I know that the coolant will always be available at the lower end of the radiator to feed the engine
Success!! Fan turned on @ ~205F