replaced water pump, car idles better, does this make sense?

[jerry]

my daily driver has been idling very rough these past couple of weeks. it was one of those things i was gonna take care of eventually. i attributed it to a minor overheating incident i had last summer. i thought perhaps i may have warped the head alittle. the compression on Nos. 2&3 were about 10-15psi less than 1&4 if i remember correctly.

anyhow, i knew i had a water leak somewhere and finally traced it to the bottom hole in the water pump.

inspection of the water pump indicated severe corrosion of the impeller and what looks like foreign object damage (FOD) on the adjacent shroud. this car sat for a couple years i was told by the PO. i'm attributing the FOD to corrosion products.

2 questions:

a) would lack of sufficient cooling explain the rough idle

what's the best way to flush the cooling system? filling it at the cap and pulling the bottom rubber hose doesn't seem like it would get the deep recesses.

btw, i replaced the radiator with one i had boiled at a shop. the other radiator is gonna get a new core.

[PSloan]

tHERE'S A BOLT UNDER THE EXHAUSE ON THE BLOCK THAT IS A DRAIN

[edgefinder]

Well I could swear mine runs better when I wash it and lube the door latches.

Honestly it would take some not normal circumstances like freezing weather and the coolant wasnt circulating so the carb wasnt warm but it wasnt showing hot on the gage. Odds are a plug wire got pushed in the dist cap, you fliked the throttle and it hit the stop a little different, the oil got topped off and it sounds smoother, battery or ground got connected better. Just keep up the normal maintainance and look for stuff like loose carb and intake bolts, cracked vacuum hoses, worn or stuck throttle linkage. Things that cause eratic running. You'll probably find something that needs attention.

Luther

[edgefinder]

Coolant flush cleaner from the pars store. Heater valve open. The block drain plug is under the exhaust like Sloan says. Run it a couple times with water to flush nooks and crannies. Be ready to replace worst hoses soon.

[Pierre]

with a lot of resistance due to trashed bearings, you would free up the engine from working hard to make the pump turn.

But I think your car is happy you replaced the pump and is thanking you by idling better.