Tried using a garden hose on the upper hose to flush the coolant and I just have most water coming back up from where I'm filling it. Going to try using a hose clamp on it tomorrow

 

Did you remove the thermostat? Cold water can't circulate with the thermostat in place.

 

Yep, I removed the thermostat. Just a little bit of water was coming out of the radiator but not enough to dislodge all the oil.

 

Alright, I was able to use a hose clamp to get it to get a good amount of oil out of the cooling system. I ran the hose for about two hours at a slow-medium flow. I checked my oil before flushing and it was just under full. I checked it after running the hose through it and it was above full, it increased by maybe a 1/4 quart. I'll check again tomorrow just to be sure.

 

Checked again today - the oil level is just above the max fill writing. Going to do a coolant pressure test to see if there's a leak somewhere into the engine.

 

Let us know what you find. Thanks for the update

 

Good update today: I tried doing a coolant pressure test but the kit I bought was broken so I just returned it. Probably don't need it anyways. I drained the oil to check for water and none came out. I think I just read the dipstick wrong before I flushed the cooling system. I moved the car to a hill when I did the flush so I must've checked the oil before it was moved. anyways - still got a lot of oil sludge in the cooling system so I'm gonna try removing the radiator and directly flush it out with the garden hose. Not much oil is in the block by the thermostat. It's all built up in the hoses and radiator.

 

It's been a while since I posted here, but I got the car back together over the weekend.

I ended up replacing the right control arm while I had the car up since the bushing was shot on that side, but then I ended up fighting the cage nut there. Then I replaced the bumper brackets, engine mount, and front trans mount. just got two more trans mounts to replace later. I tried replacing the sway bar bushings but one bolt started rolling over on me and the nut on the other side wouldn't budge so I just put it all back together since the bushings look ok. I've got non-brembo SS rotors that I've been wanting to put on since April but I guess I can wait on that later.

Anyways, about the oil: it looks like I still have oil in the cooling system but at this point, I'm just gonna keep running the car and cleaning it out as I go. temp is holding fine so there are no issues there. I've driven it about 20 miles probably now.
I'm pulling the engine out of my other car to fix bent intake valves in just one cylinder so looks like I'm waiting a while to fix the HHR if I'm still losing oil.

 

Hey all, been a little bit since my last update. The car has driven around 600 miles since I replaced the water pump and there's still oil collecting up at the radiator cap. I've just been cleaning out the oil in the hose by the radiator cap after every trip in the meantime. I've only lost maybe half a quart or less since the replacement.
Looks like I'll have to pull the engine out to figure out what's going on once I free up the lift - might be a couple months

 

And you are absolutely positive it is not ATF? That is the more likely scenario; a leaking ATF cooler.